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Key references
1381
18
RETPAHC
Counterclockwise moment Clockwise moment left hip abductor force (Ab) is about half the length of the lever arm
(BW x b) (Ab x a) (b) associated with body weight (BW). To balance the competing
(coronal plane) gravitational moments about the stance hip, the hip
abductors must produce a force about twice superincumbent body
= weight. Thus, the acetabulum is pulled inferiorly against the femoral
head not only by the body weight but also by the force created by the
activated hip abductor muscles. The sum of the muscular and gravit-
ational forces equals about 2.5 times the total weight of the person.
These downward forces on the head of the femur are counteracted by
an upward joint reaction force of equal magnitude (JRF in Fig. 81.16).
Both magnitude and direction of the joint reaction force are strongly
influenced by the pull of the hip abductor muscles.
The above analysis is for standing quietly on one limb. During
Ab
walking, however, the joint reaction force routinely reaches at least four
times body weight, reflecting both the high ground reaction forces and
the need for the hip abductor muscles to decelerate rotations of the
a pelvis (Bergmann et al 1993). Hip joint forces reach still greater values
b during running or stair-climbing (see review in Stansfield and Nicol
2002).
Compression forces produced by the gluteus medius during stance
phase are directed superiorly and slightly anteromedially within the
acetabulum (Correa et al 2010), a region naturally protected by thick
articular cartilage. In the healthy hip joint, the muscular-based compres-
sive forces serve important functions, such as helping to stabilize the
JRF
articulation and stimulate the morphological development of the
BW growing hip. Forces that cross the hip typically do not harm the joint
because they are absorbed by healthy articular cartilage and congruent
joint surfaces. Failure of these conditions to absorb forces in the joint
Fig. 81.16 While standing on one (left) lower limb, body weight (BW) line may predispose to osteoarthritis of the hip.
of force, i.e. total body weight minus the weight of the left lower limb, The three factors that influence both the magnitude and the direc-
passes just lateral to the midline, exerting a counterclockwise moment tion of compressive forces acting on the hip are the position of the
about the stance hip (BW × b). An equal but clockwise moment is centre of gravity; the abductor moment arm, which is a function of neck
required about the stance hip for mechanical equilibrium: a moment length (offset) and neck–shaft angle; and the amount of body weight.
produced by the force of the abductors (Ab), whose lever arm (a) is Shortening of the lever arm of the abductors, such as occurs in coxa
approximately half that of the lever arm (b). The two moments are in valga or excessive femoral anteversion, or in a remodelled proximal
balance when (Ab × a = BW × b). The abductor force required to maintain femur in advanced hip osteoarthritis, would increase abductor muscle
equilibrium is approximately twice that of BW, resulting in a joint reaction demand and thus increase joint reaction force as well. If the muscles
force (JRF) about 2.5 times that of total weight of the subject’s body. cannot meet this demand, the pelvis cannot be held level in standing
on one limb, a problem known as either a compensated or an uncom-
normal bipedal gait, provides the necessary coronal plane stabilization pensated Trendelenburg sign. The Trendelenburg sign is said to be
of the pelvis relative to the femoral head of the stance limb. compensated if the pelvis is brought towards the affected stance limb
The importance of hip abductor muscle activation during the stance as a way of shortening the body weight’s lever arm. Conversely, the
phase of walking can be well appreciated by understanding the simple Trendelenburg sign is said to be uncompensated if the pelvis drops away
mechanics of standing on one limb (Fig. 81.16). The lever arm (a) of from the affected stance limb uncontrollably.
Bonus e-book images
Fig. 81.1B Anteroposterior radiograph of an Fig. 81.8 An intact ligament of the head of Fig. 81.14 Hip adduction shown from a
adult male pelvis. the femur in a left adult hip. pelvic-on-femoral perspective.
Fig. 81.9 Radiograph of the left hip of a Fig. 81.15 The right lateral rotator muscles
Fig. 81.2 T1-weighted fat-saturated MR
14-year-old boy. of the hip contract to produce lateral
arthrogram of the left hip joint (coronal
rotation of the right hip, from a pelvic-on-
section).
Fig. 81.12 Hip flexion shown from two femoral perspective.
kinematic perspectives.
Fig. 81.3 Pre-surgical radiograph of a hip Imaging slideshow 81.1 Hip arthroscopy.
with a cam deformity of the femoral Fig. 81.13 Hip abduction shown from two
head–neck junction. kinematic perspectives.
KEY REFERENCES
Botser IB, Martin DE, Stout CE et al 2011 Tears of the ligamentum teres: A dynamic optimization (computerized) approach used to determine the
prevalence in hip arthroscopy using 2 classification systems. Am J Sports contributions of individual hip muscles to the total joint contact forces on a
Med 39:Suppl-25S. normal hip while walking.
The prevalence of tears of the ligamentum teres in a population of patients
Delp SL, Hess WE, Hungerford DS et al 1999 Variation of rotation moment
who underwent hip arthroscopy.
arms with hip flexion. J Biomech 32:493–501.
Correa TA, Crossley KM, Hyung JK et al 2010 Contributions of individual An estimation of the moment arm length in several hip muscles as a
muscles to hip joint contact force in normal walking. J Biomech 43: function of range of motion, based on a three-dimensional computer model
1618–22. and experimental measurements from cadaveric hips. | 1,898 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
HiP
1382
9
NOiTCES
Ferguson SJ, Bryant JT, Ganz R et al 2003 An in vitro investigation of the Neumann DA 2010a The actions of hip muscles. J Orthop Sports Phys Ther
acetabular labral seal in hip joint mechanics. J Biomech 36:171–8. 40:82–94.
A biomechanical study of how the acetabular labrum pressurizes and seals A review of the interactions among the muscles that cross the hip joint, with
the hip joint using human cadaveric material. particular reference to how these interactions influence normal movement
and physical rehabilitation of the lower limb.
Fuss FK, Bacher A 1991 New aspects of the morphology and function of the
human hip joint ligaments. Am J Anat 192:1–13. Safran MR, Giordano G, Lindsey DP et al 2011 Strains across the acetabular
An examination of how the motion of the hip affects the length and labrum during hip motion: a cadaveric model. Am J Sports Med 39:
subsequent stretch on the hip capsular ligaments in dissected, cadaveric hips. Suppl-102S.
A cadaveric study correlating the circumference strain placed across the
Leunig M, Beck M, Stauffer E et al 2000 Free nerve endings in the ligamen-
entire acetabular labrum with different hip motions.
tum capitis femoris. Acta Orthop Scand 71:452–4.
An immunohistochemical study of free nerve endings in the ligamentum Wagner FV, Negrao JR, Campos J et al 2012 Capsular ligaments of the hip:
teres (capitis femoris). anatomic, histologic, and positional study in cadaveric specimens with
MR arthrography. Radiology 263:189–98.
Martin RL, Palmer I, Martin HD 2012 Ligamentum teres: a functional
An evaluation using MRI and dissection of the length and subsequent
description and potential clinical relevance. Knee Surg Sports Traumatol
tension in the capsular ligaments of the hip in ten cadaveric specimens at
Arthrosc 20:1209–14.
the extremes of extension, flexion, abduction, adduction, and medial and
Use of a string model of the ligamentum teres to rank the relative length
lateral rotation.
changes in the structure at different hip positions. | 1,899 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
18
RETPAHC
Hip
REFERENCES
Babst D, Steppacher SD, Ganz R et al 2011 The iliocapsularis muscle: an Leunig M, Beck M, Stauffer E et al 2000 Free nerve endings in the ligamen-
important stabilizer in the dysplastic hip. Clin Ortho Rel Res 469: tum capitis femoris. Acta Orthop Scand 71:452–4.
1728–34. An immunohistochemical study of free nerve endings in the ligamentum
Bardakos NV, Villar RN 2009 The ligamentum teres of the adult hip. J Bone teres (capitis femoris).
Joint Surg Br 91:8–15. Martin RL, Palmer I, Martin HD 2012 Ligamentum teres: a functional
Bergmann G, Graichen F, Rohlmann A 1993 Hip joint loading during walk- description and potential clinical relevance. Knee Surg Sports Traumatol
ing and running, measured in two patients. J Biomech 26:969–90. Arthrosc 20:1209–14.
Birnbaum K, Prescher A, Hessler S et al 1997 The sensory innervation of the Use of a string model of the ligamentum teres to rank the relative length
hip joint – an anatomical study. Sur Radiol Anat 19:371–5. changes in the structure at different hip positions.
Botser IB, Martin DE, Stout CE et al 2011 Tears of the ligamentum teres: Myers CA, Register BC, Lertwanich P et al 2011 Role of the acetabular labrum
prevalence in hip arthroscopy using 2 classification systems. Am J Sports and the iliofemoral ligament in hip stability: an in vitro biplane fluor-
Med 39:Suppl-25S. oscopy study. Am J Sports Med 39:Suppl-91S.
The prevalence of tears of the ligamentum teres in a population of patients Neumann DA 2010a The actions of hip muscles. J Orthop Sports Phys Ther
who underwent hip arthroscopy. 40:82–94.
Cadet ER, Chan AK, Vorys GC et al 2012 Investigation of the preservation Neumann DA 2010b Kinesiology of the Musculoskeletal System: Founda-
of the fluid seal effect in the repaired, partially resected, and recon- tions for Physical Rehabilitation, 2nd ed. St Louis: Elsevier.
structed acetabular labrum in a cadaveric hip model. Am J Sports Med A review of the interactions among the muscles that cross the hip joint, with
40:2218–23. particular reference to how these interactions influence normal movement
Correa TA, Crossley KM, Kim HJ et al 2010 Contributions of individual and physical rehabilitation of the lower limb.
muscles to hip joint contact force in normal walking. J Biomech Reikeras O, Bjerkreim I, Kolbenstvedt A 1983 Anteversion of the acetabulum
43:1618–22. and femoral neck in normals and in patients with osteoarthritis of the
A dynamic optimization (computerized) approach used to determine the hip. Acta Orthop Scand 54:18–23.
contributions of individual hip muscles to the total joint contact forces on a
Safran MR, Giordano G, Lindsey DP et al 2011 Strains across the acetabular
normal hip while walking.
labrum during hip motion: a cadaveric model. Am J Sports Med 39:
Delp SL, Hess WE, Hungerford DS et al 1999 Variation of rotation moment Suppl-102S.
arms with hip flexion. J Biomech 32:493–501. A cadaveric study correlating the circumference strain placed across the
An estimation of the moment arm length in several hip muscles as a entire acetabular labrum with different hip motions.
function of range of motion, based on a three-dimensional computer model
Song Y, Ito H, Kourtis L et al 2012 Articular cartilage friction increases in
and experimental measurements from cadaveric hips.
hip joints after the removal of acetabular labrum. J Biomech 45:
Ferguson SJ, Bryant JT, Ganz R et al 2003 An in vitro investigation of the 524–30.
acetabular labral seal in hip joint mechanics. J Biomech 36:171–8. Stansfield BW, Nicol AC 2002 Hip joint contact forces in normal subjects
A biomechanical study of how the acetabular labrum pressurizes and seals and subjects with total hip prostheses: walking and stair and ramp
the hip joint using human cadaveric material. negotiation. Clin Biomech 17:130–9.
Fuss FK, Bacher A 1991 New aspects of the morphology and function of the Wagner FV, Negrao JR, Campos J et al 2012 Capsular ligaments of the hip:
human hip joint ligaments. Am J Anat 192:1–13. anatomic, histologic, and positional study in cadaveric specimens with
An examination of how the motion of the hip affects the length and MR arthrography. Radiology 263:189–98.
subsequent stretch on the hip capsular ligaments in dissected, cadaveric hips. An evaluation using MRI and dissection of the length and subsequent
tension in the capsular ligaments of the hip in ten cadaveric specimens at
Gardner E 1948 The innervation of the hip joint. Anat Rec 101:353–71.
the extremes of extension, flexion, abduction, adduction, and medial and
Gray AJ, Villar RN 1997 The ligamentum teres of the hip: an arthroscopic lateral rotation.
classification of its pathology. Arthroscopy 13:575–8.
Ward WT, Fleisch ID, Ganz R 2000 Anatomy of the iliocapsularis muscle.
Kim YT, Azuma H 1995 The nerve endings of the acetabular labrum. Clin
Relevance to surgery of the hip. Clin Ortho Rel Res 374:278–85.
Orthop 320:176–81.
1382.e1 | 1,900 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
CHAPTER
82
Knee
The knee is the largest synovial joint in the body. It consists of three ligament (overlying the posterior surface of the capsule of the knee
functional compartments that collectively form a dynamic, specialized joint), and the posterior aspect of the proximal tibia covered by popli-
hinge joint. During propulsion, the knee is able to withstand impressive teus and its fascia. The deep fascia (fascia musculorum) acts as the roof
weight-bearing loads while conducting precision movements, providing of the fossa and is continuous with the fascia lata proximally and with
a stable yet fluid mechanism for relatively efficient bipedal locomotion. the deep fascia of the leg distally. It is a dense layer that is strongly
The complex arrangement of intra- and extracapsular ligaments that reinforced by transverse fibres and is often perforated by the short
helps to counter the considerable biomechanical demands that are saphenous vein and medial and lateral sural cutaneous nerves; these
imposed on the joint can also be involved in disease (i.e. tri- structures are useful landmarks in the direct posterior approach to the
compartment disease). knee joint.
The popliteal fossa is approximately 2.5 cm wide. Distally, its con-
tents are protected and hidden by the heads of gastrocnemius, which
SKIN AND SOFT TISSUES
contact each other. The fossa contains the popliteal vessels (see Fig.
82.2; Fig. 82.4), tibial and common fibular nerves, short saphenous
SKIN vein, medial and lateral sural cutaneous nerves, posterior femoral cuta-
neous nerve, articular branch of the obturator nerve, lymph nodes, fat
Innervation and a variable number of bursae. The tibial nerve descends centrally
immediately anterior to the deep fascia, crossing the vessels posteriorly
Infrapatellar branch of the saphenous nerve from lateral to medial. The common fibular nerve descends laterally
immediately medial to the tendon of biceps femoris. When the pop-
The infrapatellar branch of the saphenous nerve reaches the anterior
liteal vessels enter the proximal region of the popliteal fossa, they
aspect of the knee from the medial side. It is invariably divided in the
maintain a side-by-side relationship, which shifts to an over–under
medial surgical approaches to the knee, which accounts for the numb-
relationship as they descend through the fossa and are held together by
ness that inevitably occurs following such procedures. A painful
dense areolar tissue within the fossa. This may potentially compromise
neuroma may form if the nerve is partially sectioned, e.g. by the incision
the popliteal artery in distal femoral fractures. The popliteal vein is
for an arthroscopy portal or a small medial arthrotomy. Unfortunately,
generally located posterior to the artery. Proximally, the vein lies lateral
the position of the nerve relative to the line of the joint is variable. In
to the artery, crossing to its medial side distally. At times, the popliteal
most cases, it crosses just below the joint line, passing over the patellar
vein may be duplicated, so that the artery lies between the veins, which
ligament at its insertion on to the tibia. For further details, see Tennant
are usually bridged by connecting channels. An articular branch from
et al (1998).
the obturator nerve descends along the artery to the knee. Six or seven
Peripatellar plexus popliteal nodes are embedded in the fat, one under the deep fascia near
the termination of the short saphenous vein, one between the popliteal
Proximal to the knee, the infrapatellar branch of the saphenous nerve
artery and knee joint, and the others intimate with the popliteal vessels.
connects with branches of the medial and intermediate femoral cutan-
eous nerves, and lateral femoral cutaneous nerve. Distal to the knee, it
connects with other branches of the saphenous nerve. This fine, subcu-
taneous network of communicating nerve fibres over and around the Descending
patella is termed the peripatellar plexus. genicular artery
Descending branch
Articular branch of
of lateral
Cutaneous vascular supply descending genicular
circumflex femoral
artery
and lymphatic drainage artery
Saphenous branch
The arterial supply of the skin covering the knee is derived from genicu- of descending
genicular artery
lar branches of the popliteal artery, the descending genicular branch of
the femoral artery, and the anterior recurrent branch of the anterior Superior medial Superior lateral
tibial artery, with small contributions from muscular branches to vastus genicular artery genicular artery
medialis and the posterior thigh muscles (Fig. 82.1). For further details,
consult Cormack and Lamberty (1994).
Tibial collateral Fibular collateral
Cutaneous veins are tributaries of vessels that correspond to the ligament ligament
named arteries. Cutaneous lymphatic drainage is initially to the super-
Patellar ligament
ficial inguinal nodes, possibly also to the popliteal nodes, and then to
Inferior lateral
the deep inguinal nodes. Inferior medial genicular artery
genicular
artery
SOFT TISSUES
Circumflex
Popliteal fossa fibular artery
The popliteal fossa (Figs 82.2–82.3) is a diamond-shaped region pos- Anterior tibial
terior to the knee, bordered by posterior compartment muscles of the recurrent artery
thigh and leg. The boundaries are biceps femoris proximolaterally;
Anterior
semimembranosus and the overlying semitendinosus proximomedi-
tibial artery
ally; the lateral head of gastrocnemius with the underlying plantaris
distolaterally; and the medial head of gastrocnemius distomedially. The
anterior boundary (or floor) of the fossa is formed, in proximodistal Fig. 82.1 The arterial anastomoses around the left knee joint, anterior
sequence, by the popliteal surface of the femur, the oblique popliteal aspect. 1383 | 1,901 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Knee
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nOITCeS
Biceps femoris Semitendinosus
Biceps
femoris Gracilis Plantaris Semimembranosus
Gracilis
Femur, popliteal surface
Semitendinosus
Tendon of semitendinosus
Semimembranosus
Tendon of semimembranosus
Tibial nerve
Gastrocnemius, lateral head Gastrocnemius, medial head
Common fibular Popliteal vein
nerve
Popliteal artery
Superior lateral
genicular artery
Lateral sural Superior medial
cutaneous genicular artery
nerve
Short saphenous
vein
Sural arteries
Muscular branches
Medial sural of tibial nerve
cutaneous
nerve
Tendon of Soleus
biceps femoris
Soleus
Gastrocnemius, Gastrocnemius,
lateral head medial head Tendon of gastrocnemius
Tendon of plantaris
Fig. 82.2 The left popliteal fossa. (With permission from Waschke J,
Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier,
Urban & Fischer. Copyright 2013.) Fascia of leg
Medial malleolus
BONES
Lateral malleolus Calcaneal tendon
FEMUR, TIBIA AND FIBULA
The femur is described on pages 1348–1353 and the tibia and fibula Calcaneal tuberosity
are described on pages 1401–1405 and 1405, respectively.
PATELLA
Fig. 82.3 Muscles of the calf, superficial view including the boundaries of
The patella is the largest sesamoid bone in the body (Figs 82.5–82.6) the popliteal fossa. (With permission from Waschke J, Paulsen F (eds),
and is embedded in the tendon of quadriceps femoris, lying anterior to Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban & Fischer.
the distal femur (femoral condyles). It is flat, distally tapered and proxi- Copyright 2013.)
mally curved, and has anterior and articular surfaces, three borders and
an apex, which is the distal end of the bone. Most surfaces and borders
are palpable. With the knee in extension, the apex is positioned proxi- retinaculum receives contributions from the iliotibial tract. Ossification
mal to the line of the knee joint by 1–2 cm. occasionally extends from the lateral margin of the patella into the
The subcutaneous, convex anterior surface is perforated by numer- tendon of vastus lateralis.
ous nutrient vessels. It is longitudinally ridged, separated from the skin The shape of the patella can vary and certain configurations are
by the subcutaneous prepatellar bursa, and covered by an expansion associated with patellar instability. Not infrequently, a bipartite and,
from the tendon of quadriceps femoris, which blends distally with less commonly, a tripartite patella are seen on imaging. The bone seems
superficial fibres of the patellar ligament (inaccurately named because to be in separate parts, usually with a smaller superolateral fragment:
this structure is the continuation of the tendon of quadriceps femoris). this has long been attributed to the presence of a separate ossification
The posterior surface has a proximal smooth, oval articular area, crossed centre but, in some cases, could represent failed union following either
by a smooth vertical ridge, which fits the intercondylar groove on the a stress fracture or a violent contraction of quadriceps femoris (e.g.
femoral patellar surface and divides the patellar articular area into landing on the feet after jumping from a substantial height) resulting
medial and lateral facets; the lateral is usually larger. Each facet is in a traumatic fracture.
divided by faint horizontal lines into approximately equal thirds. A
seventh ‘odd’ facet is present as a narrow strip along the medial border Structure The patella consists of more or less uniformly dense trabec-
of the patella; it contacts the medial femoral condyle in extreme knee ular bone, covered by a thin compact lamina. Trabeculae beneath the
flexion. Distal to the articular surface, the apex is roughened by the anterior surface are parallel to the surface; elsewhere, they radiate from
attachment of the patellar ligament. Proximal to this, the area between the articular surface into the substance of the bone.
the roughened apex and the articular margin is covered by an infrapatel-
lar fat pad. The patellar articular cartilage is the thickest in the body, Muscle attachments Quadriceps femoris is attached to the superior
reflecting the magnitude of the stresses to which it is subjected. surface, except near its posterior margin; the attachment extends distally
The thick superior border (surface) slopes anteroinferiorly. The on to the anterior surface. The attachment for rectus femoris is antero-
medial and lateral borders are thinner and converge distally; the inferior to that for vastus intermedius. Rough markings can be traced
expansions of the tendons of vasti medialis and lateralis (medial and in continuity around the periphery of the bone from the anterosuperior
lateral patellar retinacula, respectively) are attached to them. The lateral surface to the deep surface of the apex. Those at the lateral and medial | 1,902 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Joints
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28
ReTPAHC
Tibial nerve Popliteal artery 4
Plantaris Inferior medial genicular artery
1
Popliteus
Anterior tibial artery
5
Soleus Soleus
Tibialis posterior
Fibular artery
Posterior tibial artery
2
6
3
Tibial nerve
A
Flexor digitorum longus 1
4
Fibularis longus
Flexor hallucis longus
5
6
2
Posterior tibial artery 7
Fibularis brevis
Tendon of tibialis posterior
3
Medial malleolar branches
Lateral malleolar 8
Tendon of flexor hallucis longus
branches
Calcaneal tendon
9
B
Calcaneal branches
Calcaneal anastomosis
Fig. 82.5 A, Left patella, anterior aspect. Key: 1, area of attachment of
rectus femoris; 2, medial border: attachment of medial retinaculum
(expansion); 3, apex; 4, area of attachment of vastus intermedius; 5,
markings of attachment of tendon of quadriceps femoris; 6, lateral border:
attachment of lateral retinaculum (expansion). B, Left patella, articular
Fig. 82.4 The left popliteal, posterior tibial and fibular arteries, posterior (posterior) surface. Key: 1, upper lateral facet: in contact with femur in
aspect. (With permission from Waschke J, Paulsen F (eds), Sobotta Atlas flexion of the knee; 2, lower lateral facet: in contact with femur in
of Human Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.) extension of the knee; 3, area overlain by edge of circumferential fat pad;
4, upper medial facet: in contact with femur in flexion of the knee; 5,
medial vertical (‘odd’) facet: in contact with femur in extreme flexion of
borders represent the attachments of vasti lateralis and medialis, and the knee; 6, lower medial facet: in contact with femur in extension of the
those at the apex represent the attachment of the patellar ligament. knee; 7, ridge; 8, area covered by infrapatellar fat pad; 9, area for
attachment of patellar ligament.
Vascular supply The arterial supply of the patella is derived from
the genicular anastomosis, particularly from the genicular branches of
the popliteal artery and from the anterior tibial recurrent artery. An latter case, the joint surfaces are inclined at an angle of greater than
anatomical study in children and fetuses confirmed that this network 20°). The fibular facet is usually elliptical or circular, and almost flat or
is already well developed in these age groups (Hamel et al 2012). slightly grooved. The surfaces are covered with hyaline cartilage.
The volume of articular cartilage peaks at Tanner stage 2; boys gain
Ossification Several centres appear during the third to sixth years and articular cartilage faster than girls. The rate of cartilaginous volume
these coalesce rapidly. Accessory marginal centres appear later and fuse development is +233 µl/year for the patella, +350 µL/year for the
with the central mass. medial tibial compartment and +256 µL/year for the lateral tibial com-
partment (Jones et al 2003).
JOINTS
Fibrous capsule The capsule is attached to the margins of the articu-
lar surfaces of the tibia and fibula, and is thickened anteriorly and
SUPERIOR TIBIOFIBULAR JOINT posteriorly.
The superior (proximal) tibiofibular joint is a synovial joint (plane Ligaments The ligaments of the superior tibiofibular joint are not
variety) between the lateral tibial condyle and head of the fibula. entirely separate from the capsule. The anterior ligament is made up of
two or three flat bands, which pass obliquely up from the fibular head
Articulating surfaces The articulating surfaces vary in size, form to the front of the lateral tibial condyle in close relation to the tendon
and inclination. The joint line may be transverse or oblique (in the of biceps femoris. The posterior ligament is a thick band that ascends | 1,903 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Knee
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9
nOITCeS
2
1
1
2
3
3
2
2
4 4
2
A B
Fig. 82.6 Anteroposterior (A) and lateral (B) radiographs of the knee of a boy aged 14 years. Key: 1, patella; 2, cartilaginous growth plates;
3, intercondylar eminence; 4, prolongation of proximal tibial epiphysis and growth plate forming the tibial tuberosity.
obliquely between the posterior aspect of the fibular head and the flexion, when the highest lateral patellar facet contacts the anterior part
lateral tibial condyle, covered by the popliteal tendon. of the lateral femoral condyle. As the knee extends, the middle patellar
facets contact the lower half of the femoral surface; in full extension,
Synovial membrane The synovial membrane of the superior tibio- only the lowest patellar facets are in contact with the femur. In summary,
fibular joint is occasionally continuous with that of the knee joint via on flexion, the patellofemoral contact point moves proximally and the
the subpopliteal recess. contact area broadens to cope with the increasing stress that accompa-
nies progressive knee flexion.
Vascular supply and lymphatic drainage The superior tibio-
fibular joint receives an arterial supply from the anterior and posterior Patellar ligament sheath and patellar ligament The patellar
tibial recurrent branches of the anterior tibial artery. Lymphatics follow ligament is a continuation of the tendon of quadriceps femoris and
the arteries and drain to the popliteal nodes. therefore is inaccurately named. It continues from the patella to the
tibial tuberosity (see Figs 80.28, 80.31). It is strong, flat and 6–8 cm in
Innervation The superior tibiofibular joint is innervated by branches length. Proximally, it is attached to the apex of the patella and adjoining
from the common fibular nerve and from the nerve to popliteus. margins, to roughened areas on the anterior surface and to a depression
on the distal posterior patellar surface. Distally, it is attached to the
Factors maintaining stability Stability of the superior tibiofibular superior smooth area of the tibial tuberosity. This attachment is oblique,
joint is maintained by the fibrous capsule and the anterior and posterior and is more distal laterally. Its superficial fibres are continuous over the
ligaments, assisted by the biceps femoris tendon and the interosseous patella with the tendon of quadriceps femoris, the medial and lateral
membrane of the leg. parts of which descend, flanking the patella, to the sides of the tibial
tuberosity, where they merge with the fibrous capsule as the medial and
Movements Very little movement other than limited gliding takes lateral patellar retinacula. The patellar ligament is separated from the
place at the superior tibiofibular joint. Some movement must occur in synovial membrane by a large infrapatellar fat pad and from the tibia
conjunction with movement at the inferior tibiofibular joint; however, by a bursa, and lies within its own well-defined sheath.
surgical fusion (arthrodesis) of the superior tibiofibular joint seems to In the procedure of tibial osteotomy, the tibia is cut transversely just
have no effect on movements of the ankle joint. above the insertion of the patellar ligament. Failure to appreciate the
obliquity of the tibial attachment of the tendon may lead to inadvertent
Relations The common fibular nerve runs posterior to the head of division of the tendon during this procedure. The middle third of the
the fibula, medial to the tendon of biceps femoris, which is closely patellar ligament may be harvested for surgical repair of a cruciate
associated with the anterior capsule. The anterior and posterior tibial ligament.
branches of the popliteal artery, and the fibular artery are all vulnerable All other aspects of the patellofemoral joint are described with the
inferomedial to the joint. tibiofemoral joint.
PATELLOFEMORAL JOINT TIBIOFEMORAL JOINT
The patellofemoral joint is a synovial joint and is part of the knee joint. The tibiofemoral joint is a complex synovial joint and is part of the
knee joint.
Articulating surfaces The articular surface of the patella is adapted
to that of the femur. The latter extends on to the anterior surfaces of Articulating surfaces
both femoral condyles like an inverted U. Since the whole area is Proximal tibial surface
concave transversely and convex in the sagittal plane, it is an asymmetri- The proximal tibial surface (unofficially referred to as the tibial plateau)
cal sellar surface. The ‘odd’ facet on the articular surface of the patella slopes posteriorly and downwards relative to the long axis of the shaft
contacts the anterolateral aspect of the medial femoral condyle in full (Fig. 82.7). The tilt, which is maximal at birth, decreases with age, and | 1,904 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Transverse
1 ligament Anterior cruciate
ligament
5
2 Lateral
6 meniscus Medial
meniscus
7
Posterior
meniscofemoral
8 ligament Posterior cruciate
3
ligament
4
9
Fig. 82.8 The superior aspect of the left tibia, showing the menisci and
the attachments of the cruciate ligaments. (With permission from Drake
10
RL, Vogl AW, Mitchell A, et al (eds), Gray’s Atlas of Anatomy, Elsevier,
Churchill Livingstone. Copyright 2008.)
Fig. 82.7 The left tibial plateau. Key: 1, tibial tuberosity; 2, attachment of
anterior horn, lateral meniscus; 3, lateral condyle; 4, attachment of
posterior horn, lateral meniscus; 5, attachment of anterior horn, medial
meniscus; 6, attachment of anterior cruciate ligament; 7, medial condyle;
1 6
8, intercondylar eminence; 9, attachment of posterior horn, medial
meniscus; 10, attachment of posterior cruciate ligament.
is more marked in habitual squatters. The tibial plateau presents medial
and lateral articular surfaces (facets) for articulation with the corre- 2 5
sponding femoral condyles. The posterior surface, distal to the articular
margin, displays a horizontal, rough groove to which the capsule and 4
posterior part of the tibial collateral ligament are attached. The antero- 3
medial surface of the medial tibial condyle is a rough strip, separated
from the medial surface of the tibial shaft by an inconspicuous ridge.
The medial patellar retinaculum is attached to the medial tibial condyle
along its anterior and medial surfaces, which are marked by vascular
foramina. Fig. 82.9 Left knee joint, T1-weighted coronal magnetic resonance image
The medial articular surface is oval (long axis anteroposterior) and (MRI). Key: 1, posterior cruciate ligament; 2, tibial collateral ligament;
3, medial meniscus; 4, lateral meniscus; 5, fibular collateral ligament;
longer than the lateral articular surface. Around its anterior, medial and
6, anterior cruciate ligament.
posterior margins, it is related to the medial meniscus; the meniscal
imprint, wider posteriorly and narrower anteromedially, is often dis-
cernible. The surface is flat in its posterior half and the anterior half A depression behind the base of the medial intercondylar tubercle is
slopes superiorly about 10°. The meniscus covers much of the posterior for the attachment of the posterior horn of the medial meniscus. The
surface so that, overall, a concave surface is presented to the medial rest of the area is smooth and provides attachment for the posterior
femoral condyle. Its lateral margin is raised as it reaches the intercondy- cruciate ligament, spreading back to a ridge to which the capsule is
lar region. attached.
The lateral tibial condyle overhangs the shaft of the tibia postero- In a study of Nigerian children, the mean intercondylar distance was
laterally above a small circular facet for articulation with the fibula. The 0.2 cm at 1 year of age and there was no significant increase in this
lateral articular surface is more circular and coapted to its meniscus. In distance by the age of 10 years (Omololu et al 2003).
the sagittal plane, the articular surface is fairly flat centrally, and ant-
eriorly and posteriorly the surface slopes inferiorly. Overall, this creates Femoral surface
a rather convex surface so that, with the lateral femoral condyle in The femoral condyles, bearing articular cartilage, are almost wholly
contact, there are anterior and posterior recesses (triangular in section), convex. Opinions as to the contours of their sagittal profiles tend to
which are occupied by the anterior and posterior meniscal ‘horns’. vary. One view is that they are spiral with a curvature increasing pos-
Elsewhere, the surface has a raised medial margin that spreads to the teriorly (‘a closing helix’), that of the lateral condyle being greater. An
lateral intercondylar tubercle. Its articular margins are sharp, except alternative view is that the articular surface for contact with the tibia on
posterolaterally, where the edge is rounded and smooth: here the the medial femoral condyle describes the arcs of two circles. According
tendon of popliteus is in contact with bone. to this view, the anterior arc makes contact with the tibia near extension
and is part of a virtual circle of larger radius than the more posterior
Intercondylar area arc, which makes contact during flexion. The lateral femoral condyle is
The rough-surfaced area between the condylar articular surfaces is nar- believed to describe a single arc and thus to possess a single radius of
rowest centrally where there is an intercondylar eminence, the edges of curvature.
which project slightly proximally as the lateral and medial intercon- Tibiofemoral congruence is improved by the menisci, which are
dylar tubercles. The intercondylar area widens behind and in front of shaped to produce concavity of the surfaces presented to the femur; the
the eminence as the articular surfaces diverge (see Fig. 82.7; Fig. 82.8). combined lateral tibiomeniscal surface is deeper. The lateral femoral
The anterior intercondylar area is widest anteriorly. Anteromedially, condyle has a faint groove anteriorly, which rests on the peripheral edge
anterior to the medial articular surface, a depression marks the site of of the lateral meniscus in full extension. A similar groove appears on
attachment of the anterior horn of the medial meniscus. Behind this, a the medial condyle but does not reach its lateral border, where a narrow
smooth area receives the anterior cruciate ligament. The anterior horn strip contacts the medial patellar articular surface in full flexion. These
of the lateral meniscus is attached anterior to the intercondylar emi- grooves demarcate the femoral patellar and condylar surfaces. The dif-
nence, lateral to the anterior cruciate ligament. The eminence, with ferences between the shapes of the articulating surfaces correlate with
medial and lateral tubercles, is the narrow central part of the area. The the movements of the knee joint.
raised tubercles are thought to provide a slight stabilizing influence on
the femur. It is believed that the eminence becomes prominent once Menisci
walking commences and that the tibial condyles transmit the weight of The menisci (semilunar cartilages) are crescentic, intracapsular, fibro-
the body through the tibia. cartilaginous laminae (see Fig. 82.8; Fig. 82.9). They serve to widen,
The posterior horn of the lateral meniscus is attached to the posterior deepen and prepare the tibial articular surfaces that receive the femoral
slope of the intercondylar area. The posterior intercondylar area inclines condyles. Their peripheral attached borders are thick and convex, and
down and backwards behind the posterior horn of the lateral meniscus. their free, inner borders are thin and concave. Their peripheries are | 1,905 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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vascularized by capillary loops from the fibrous capsule and synovial Watanabe et al (1979). In its mildest form, the partial discoid meniscus
membrane, while their inner regions are less vascular. Tears of the is simply a wider form of the normal lateral meniscus. The acute, medial
menisci are common. Peripheral tears (e.g. in the vascularized zone) free edge is interposed between the femoral and tibial condyles but it
have the potential to heal satisfactorily, especially with surgical inter- does not completely cover the tibial plateau. A complete discoid menis-
vention. Tears in the less vascular or inner zones seldom heal spontane- cus appears as a biconcave disc with a rolled medial edge and covers
ously; if surgery is indicated, these menisci are often resected. The the lateral tibial plateau. The Wrisberg type of meniscus has the same
meniscal horns are richly innervated compared with the remainder of shape as a complete discoid meniscus but its only peripheral posterior
the meniscus. The central one-third is devoid of innervation (Gronblad attachment is by the meniscofemoral ligaments. In this case, the normal
et al 1985). The proximal surfaces are smooth and concave, and in tibial attachment of the posterior horn of the lateral meniscus is lacking
contact with the articular cartilage on the femoral condyles. The distal but the posterior meniscofemoral ligament persists. As a result, this type
surfaces are smooth and flat, resting on the tibial articular cartilage. of meniscus is attached anteriorly to the tibia and posteriorly to the
Each covers approximately two-thirds of its tibial articular surface. femur, which renders the posterior horn unstable. Under these circum-
Canal-like structures open on to the surface of the menisci in infants stances, the meniscus is liable to become caught between the femur and
and young children, and may transport nutrients to deeper, less tibia: this accounts for the classic presenting symptom of the ‘clunking
vascular areas. knee’ in some patients. The aetiology of discoid meniscus is not clear.
Two structurally different regions of the menisci have been identi- Most are asymptomatic and are often found by chance at arthroscopy.
fied. The inner two-thirds of each meniscus consist of radially organized However, they may cause difficulty in gaining access to the lateral com-
collagen bundles, and the peripheral one-third consists of larger circum- partment at arthroscopy. A discoid medial meniscus is extremely rare.
ferentially arranged bundles (Ghadially et al 1983). Thinner collagen
bundles parallel to the surface line the articular surfaces of the inner Transverse ligament of the knee
part, while the outer portion is covered by synovium. This structural The transverse ligament of the knee connects the anterior convex margin
arrangement suggests specific biomechanical functions for the two of the lateral meniscus to the anterior horn of the medial meniscus (see
regions: the inner portion of the meniscus is suited to resisting compres- Fig. 82.8). It varies in thickness and is often absent. Its exact role is
sive forces while the periphery is capable of resisting tensional forces. conjectural, although one study found that the ligament was slightly
With ageing and degeneration, compositional changes occur within the taut in knee extension (Tubbs et al 2008); presumably, it helps to
menisci, which reduce their ability to resist tensional forces. Outward decrease tension generated in the longitudinal circumferential fibres of
displacement of the menisci by the femoral condyles is resisted by firm the menisci when the knee is subjected to load. A posterior menisco-
anchorage of the peripheral circumferential fibres to the intercondylar meniscal ligament is sometimes present.
bone at the meniscal horns.
The menisci spread load by increasing the congruity of the articul- Meniscofemoral ligaments
ation, provide stability by their physical presence and proprioceptive The two meniscofemoral ligaments connect the posterior horn of the
feedback, and may cushion the underlying bone from the considerable lateral meniscus to the inner (lateral) aspect of the medial femoral
forces generated during extremes of flexion and extension of the knee. condyle (Figs 82.10–82.11). The anterior meniscofemoral ligament
(ligament of Humphrey) passes anterior to the posterior cruciate liga-
Medial meniscus ment. The posterior meniscofemoral ligament (ligament of Wrisberg)
The medial meniscus is broader posteriorly and is almost a semicircle passes behind the posterior cruciate ligament and attaches proximal to
in shape (see Fig. 82.8). It is attached by its anterior horn to the anterior the margin of attachment of the posterior cruciate.
tibial intercondylar area in front of the anterior cruciate ligament; the
posterior fibres of the anterior horn are continuous with the transverse
ligament of the knee (when present). The anterior horn is in the floor
of a depression medial to the upper part of the patellar ligament. The
posterior horn is fixed to the posterior tibial intercondylar area, between
1
the attachments of the lateral meniscus and posterior cruciate ligament.
Its peripheral border is attached to the fibrous capsule and the deep
2
surface of the tibial collateral ligament. The tibial attachment of the
meniscus is known as the ‘coronary or meniscotibial ligament’. Col-
lectively, these attachments ensure that the medial meniscus is relatively
3
fixed and moves much less than the lateral meniscus.
6
4
Lateral meniscus
The lateral meniscus forms approximately four-fifths of a circle and
covers a larger area than the medial meniscus (see Fig. 82.8). Its breadth, 5
except at its short tapered horns, is more or less uniform. It is grooved
posterolat erally by the tendon of popliteus, which separates it from the
fibular collateral ligament. Its anterior horn is attached in front of the A
intercondylar eminence, posterolateral to the anterior cruciate ligament,
with which it partly blends. Its posterior horn is attached behind this
eminence, in front of the posterior horn of the medial meniscus. Its
anterior attachment is contorted so that the free margin faces postero-
superiorly, and the anterior horn rests on the anterior slope of the
lateral intercondylar tubercle. Near its posterior attachment, it com-
monly sends a posterior meniscofemoral ligament superomedially
behind the posterior cruciate ligament to the medial femoral condyle.
An anterior meniscofemoral ligament may also connect the posterior
1
horn to the medial femoral condyle anterior to the posterior cruciate
ligament. The meniscofemoral ligaments are often the sole attachments 4
of the posterior horn of the lateral meniscus. More laterally, part of the 2
tendon of popliteus is attached to the lateral meniscus, and so mobility 3
of its posterior horn may be controlled by the meniscofemoral liga-
ments and by popliteus. A meniscofibular ligament occurs in most knee
joints. As with the medial meniscus, there is a tibial attachment via the
so-called coronary ligament, but the meniscus has no peripheral bony B
attachment in the region of popliteus; in the surgical literature, this gap
is referred to as the popliteus hiatus. Fig. 82.10 A, The anterior cruciate ligament, proton density (PD)-weighted
sagittal MRI. Key: 1, suprapatellar bursa; 2, patella; 3, infrapatellar fat
Discoid lateral meniscus A discoid lateral meniscus occasionally pad; 4, femoral articular cartilage; 5, patellar ligament; 6, anterior cruciate
occurs, often bilaterally. The distinguishing features of a discoid lateral ligament. B, Anterior cruciate ligament: T2-weighted sagittal MRI. Key:
meniscus are its shape and posterior ligamentous attachments. The 1, femoral articular cartilage; 2, infrapatellar fat pad; 3, patellar ligament;
following classification of the abnormality is based on the work of 4, anterior cruciate ligament. | 1,906 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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A
Femur
6
1
Tendon of
adductor magnus
Plantaris
Gastrocnemius,
2 lateral head Gastrocnemius,
5
Fibular collateral medial head
ligament
Oblique popliteal
3 Arcuate popliteal ligament
ligament
Tibial collateral
Tendon of ligament
biceps femoris
Tendon of
semimembranosus
A 4 Popliteus
1
2 Popliteus
3 Fibula
Tibia
4
B
5 Tendon of
adductor magnus
8 Tendon of gastrocnemius, Tendon of
6 lateral head gastrocnemius,
medial head
Anterior cruciate
7 Femur,
ligament
B medial condyle
Femur, lateral Posterior
Fig. 82.11 A, Posterior cruciate ligament, PD-weighted sagittal MRI. condyle meniscofemoral
Key: 1, epiphyseal line; 2, femoral articular cartilage; 3, patellar ligament; Tendon of ligament
4, popliteus; 5, posterior cruciate ligament; 6, gastrocnemius. B, Medial popliteus Tibial
collateral ligament
meniscus, PD-weighted sagittal MRI. Key: 1, suprapatellar fat pad; Lateral
2, tendon of quadriceps femoris; 3, patellar articular cartilage; 4, patella; meniscus Tendon of
5, femoral articular cartilage; 6, patellar ligament; 7, infrapatellar fat pad; Fibular collateral semimembranosus
8, medial meniscus. ligament Oblique popliteal
Tibia, lateral ligament
condyle Posterior cruciate
ligament
Anatomical studies found that at least one meniscofemoral ligament Posterior ligament of
fibular head Popliteus, aponeurosis
was almost always present in the cadaveric knees examined, while both
sometimes coexisted (Gupte et al 2003). Biomechanical studies have Fibula, head Popliteus
revealed the cross-sectional area and strength of the meniscofemoral Fig. 82.12 A posterior dissection of the knee. A, Capsule intact.
ligaments to be comparable to those of the posterior fibre bundle of B, Capsule removed. (With permission from Waschke J, Paulsen F (eds),
the posterior cruciate ligament. Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban & Fischer.
The meniscofemoral ligaments are believed to act as secondary Copyright 2013.)
restraints, supporting the posterior cruciate ligament in minimizing
displacement caused by posteriorly directed forces on the tibia. These
ligaments are also involved in controlling the motion of the lateral
meniscus in conjunction with the tendon of popliteus during knee Medial soft tissues
flexion. The medial soft tissues (see Fig. 80.28; Fig. 82.12) are arranged in three
layers (Warren and Marshall 1979).
Soft tissues
Layer 1 Layer 1 is the most superficial and is the deep fascia that
Recent advances in imaging and surgery of knee ligaments have con- invests sartorius. The saphenous nerve and its infrapatellar branch are
tributed to an improved understanding of the anatomy of the medial superficial to the deep fascia of the leg. Sartorius inserts into the fascia
and lateral soft tissues of the knee. as an expansion rather than as a distinct tendon. The fascia spreads
inferiorly and anteriorly to lie superficial to the distinct and readily
Capsule and retinacula
identifiable tendons of gracilis and semitendinosus and their insertions.
The joint capsule is a fibrous membrane of variable thickness. Anterior ly, The latter two tendons are commonly harvested for surgical reconstruc-
it is replaced by the patellar ligament and does not pass proximal to tion of damaged cruciate ligaments. To gain access to them, the upper
the patella or over the patellar area. Elsewhere, it lies deep to expansions edge of sartorius can be identified. The sartorius (layer 1) fascia is then
from vasti medialis and lateralis, separated from them by a plane of incised to reveal the tendons. Deep to the tendons is the anserine bursa,
vascularized loose connective tissue. The expansions are attached to the which overlies the superficial part of the tibial collateral ligament; this
patellar margins and patellar ligament, extending back to the corre- bursa sometimes becomes inflamed, especially in track and field ath-
sponding collateral (tibial and fibular) ligaments and distally to the letes. Posteriorly, layer 1 overlies the tendons of gastrocnemius and the
tibial condyles. They form medial and lateral patellar retinacula, the structures of the popliteal fossa. Anteriorly, layer 1 blends with the
lateral being reinforced by the iliotibial tract. anterior limit of layer 2 and the medial patellar retinaculum. More
Posteriorly, the capsule contains vertical fibres that arise from the inferiorly, layer 1 blends with the periosteum.
articular margins of the femoral condyles and intercondylar fossa, and A condensation of tissue passes from the medial border of the
from the proximal tibia. The fibres mainly pass downwards and some- patella to the medial epicondyle of the femur (the medial patellofemo-
what medially. The oblique popliteal ligament is a well-defined thicken- ral ligament), the anterior horn of the medial meniscus (the menisco-
ing across the posteromedial aspect of the capsule, and is one of the patellar ligament), and the medial tibial condyle (the patellotibial
major extensions from the tendon of semimembranosus. ligament). | 1,907 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Layer 2 Layer 2 is the plane of the superficial part of the tibial col- patella. The latter is thicker and subdivided into three parts: the lateral
lateral ligament, which means that the tendons of gracilis and semi- patellofemoral ligament, running from the lateral patellar border to the
tendinosus lie between layers 1 and 2. The superficial part of the tibial lateral epicondyle of the femur; the transverse retinaculum, running
collateral ligament has vertical and oblique portions. The former con- from the iliotibial tract to the mid-patella; and the patellotibial band,
tains vertically orientated fibres that pass from the medial epicondyle running from the patella to the lateral tibial condyle.
of the femur to a large insertion on the medial surface of the proximal The fascia lata and the iliotibial tract lie posterior to the lateral reti-
end of the tibial shaft. It extends to an area about 5 cm distal to the naculum. They come together distally to insert on to the tibia at a
joint line. Its anterior edge is rolled and easily seen just posterior to the tubercle (Gerdy’s tubercle) on the anterolateral proximal tibia; some
insertions of gracilis and semitendinosus once layer 1 has been opened. fibres continue to insert on the tibial tuberosity. Proximally, the fascia
The posteriorly placed oblique fibres run posteroinferiorly from the lata merges with the lateral intermuscular septum. Posteriorly, it blends
medial epicondyle of the femur to blend with the underlying layer 3 with the fascia over biceps femoris. Here, as it emerges from behind the
(capsule), effectively to insert on the posteromedial tibial articular biceps femoris tendon, the common fibular nerve lies in a thin layer of
margin and posterior horn of the medial meniscus. This area is re- fat bound by the fascia.
inforced by a part of the insertion of semimembranosus. There is a The fibular collateral ligament arises from the lateral epicondyle of
vertical split in layer 2 anterior to the superficial part of the tibial col- the femur posterior to the popliteus insertion and just proximal to the
lateral ligament. The fibres anterior to the split pass superiorly to blend groove for popliteus. It is a cord-like structure that passes distally, super-
with vastus medialis fascia and layer 1 in the medial patellar retinacu- ficial to the popliteus tendon and deep to the lateral retinaculum, to
lum. The fibres posterior to the split pass superiorly to the medial epi- attach to the fibular head, where it blends with the biceps femoris
condyle and thence anteriorly as the medial patellofemoral ligament. tendon just anterior to the apex of the head of the fibula. It is separated
from the capsule by a thin layer of fat and the inferior lateral genicular
Layer 3 Layer 3 is the capsule of the knee joint and can be separated vessels.
from layer 2 everywhere except anteriorly close to the patella, where it The single most important stabilizer of the posterolateral knee is the
blends with the more superficial layers. Deep to the superficial part of popliteofibular (short external lateral) ligament. It passes from the
the tibial collateral ligament it is thick and has vertically orientated popliteus tendon at a level just below the joint line, posteriorly, laterally
fibres that make up the deep medial part of the tibial collateral liga- and inferiorly, to the apex of the head of the fibula. As a passive ‘tether’
ment. It sends fibres to the medial meniscus. Anteriorly, the separation combined with the popliteus tendon proximal to it, it resists lateral
of the superficial and deep parts of the tibial collateral ligament is rotation of the tibia. Its connection to the tendon of popliteus also
distinct. Posteriorly, layers 2 and 3 blend to form a conjoined postero- allows ‘dynamic’ tensioning.
medial capsule. The fabellofibular ligament is a condensation of fibres that runs
either from the fabella (a sesamoid bone sometimes found within the
Lateral soft tissues
tendon of the lateral head of gastrocnemius) or from the lateral head
The lateral soft tissues (see Fig. 82.12; Fig. 82.13) are also arranged in of gastrocnemius (if the fabella is absent), to the apex of the head of
three layers (Seebacher et al 1982), which collectively have been referred the fibula. The arcuate ligament is a condensation of fibres that runs
to as the lateral collateral ligamentous complex (Nissman et al 2008). from the apex of the head of the fibula, posteromedially over the emerg-
The most superficial layer is the lateral patellar retinaculum. The middle ing tendon of popliteus below the level of the tibial joint surface, to the
layer consists of the fibular collateral popliteofibular, fabellofibular and tibial intercondylar area. The lateral joint capsule is thin and blends
arcuate ligaments. The recently described anterolateral ligament of the posteriorly with the arcuate ligament. Anteriorly, it forms the weak, lax
knee may exist in this layer (Claes et al 2013). The deep layer is the coronary or meniscotibial ligament, which attaches the inferior border
lateral part of the capsule. of the meniscus to the lateral tibia.
The lateral patellar retinaculum consists of superficial oblique and
deep transverse portions. The former runs from the iliotibial tract to the Ligaments
Cruciate ligaments
The cruciate ligaments, so named because they cross each other, are very
strong, richly innervated intracapsular structures. The point of crossing
Suprapatellar bursa
is located a little posterior to the articular centre. They are named ant-
Tendon of erior and posterior with reference to their tibial attachments (Figs
quadriceps femoris 82.14–82.15; see Fig. 82.17). A synovial membrane almost surrounds
the ligaments but is reflected posteriorly from the posterior cruciate
ligament to adjoining parts of the capsule; the intercondylar part of the
posterior region of the fibrous capsule therefore has no synovial
Subfascial
prepatellar bursa covering.
A B
Patellar ligament
Fibular collateral ligament Intercondylar region
Lateral meniscus Anterior cruciate
Tendon of popliteus
ligament
Deep infrapatellar bursa
Arcuate popliteal ligament Posterior cruciate
ligament
Tendon of biceps femoris Medial meniscus
Lateral meniscus
Fig. 82.13 The left knee joint, lateral aspect. The synovial cavity is Fig. 82.14 The left knee joint. A, Anterior aspect in full flexion.
distended and the synovial membrane appears grey. (With permission B, Posterior aspect in extension. (With permission from Drake RL, Vogl
from Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, AW, Mitchell A, et al (eds), Gray’s Atlas of Anatomy, Elsevier, Churchill
15th ed, Elsevier, Urban & Fischer. Copyright 2013.) Livingstone. Copyright 2008.) | 1,908 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Medial femoral condyle Fig. 82.15 The
intercondylar notch at Tendon of quadriceps
arthroscopy, showing femoris
the anterior cruciate
and transverse
Suprapatellar bursa
ligaments of the knee.
(Courtesy of Smith and
Nephew Endoscopy.)
Subcutaneous Fibrous capsule
prepatellar bursa
Infrapatellar pad of fat, Anterior
extending into cruciate ligament
infrapatellar fold
Patellar ligament Posterior
cruciate ligament
Transverse Anterior cruciate Deep infrapatellar bursa
ligament ligament
Anterior cruciate ligament The anterior cruciate ligament is
Fig. 82.16 A sagittal section through the left knee joint, lateral aspect.
attached to the anterior intercondylar area of the tibia, just anterior and
slightly lateral to the medial intercondylar tubercle, partly blending
with the anterior horn of the lateral meniscus (see Fig. 82.8). It ascends
posterolaterally, twisting on itself and fanning out to attach high on the
posteromedial aspect of the lateral femoral condyle (Girgis et al 1975).
The average length and width of an adult anterior cruciate ligament are
38 mm and 11 mm, respectively. It is formed of two, or possibly three,
Femur
functional bundles that are not apparent to the naked eye but can be
demonstrated by microdissection techniques. The bundles are named Articular capsule
anteromedial, intermediate and posterolateral, according to their tibial Posterior cruciate
attachments (Amis and Dawkins 1991). ligament
Posterior cruciate ligament The posterior cruciate ligament is Ligamentum
mucosum
thicker and stronger than the anterior cruciate ligament (see Fig. 82.8), overlying
the average length and width of an adult posterior cruciate ligament anterior
being 38 mm and 13 mm, respectively. It is attached to the lateral cruciate ligament
surface of the medial femoral condyle and extends up on to the anterior
Alar folds overlying
part of the roof of the intercondylar fossa, where its attachment is the infrapatellar fat pad
extensive in the anteroposterior direction. Its fibres are adjacent to the
articular surface. They pass distally and posteriorly to a fairly compact
attachment posteriorly in the intercondylar region and in a depression
on the adjacent posterior tibia. This gives a fan-like structure in which
fibre orientation is variable. Anterolateral and posteromedial bundles
Patella
have been defined; they are named (against convention) according to
their femoral attachments. The anterolateral bundle tightens in flexion
while the posteromedial bundle is tight in extension of the knee. Each
Tendon of quadriceps
bundle slackens as the other tightens. Unlike the anterior cruciate liga- femoris
ment, it is not isometric during knee motion, i.e. the distance between
attachments varies with knee position. The posterior cruciate ligament
ruptures less commonly than the anterior cruciate ligament and rupture
Fig. 82.17 The left knee joint in full flexion. The tendon of quadriceps
is usually better tolerated by patients than rupture of the anterior cruci-
femoris has been sectioned and the patella retracted distally. Compare
ate ligament.
with Figure 82.14A.
Synovial membrane, plicae and fat pads
it can be thickened and inflamed, usually following acute or chronic
The synovial membrane of the knee is the most extensive and complex trauma.
in the body. It forms a large suprapatellar bursa between quadriceps The suprapatellar plicae are remnants of an embryonic septum that
femoris and the lower femoral shaft proximal to the superior patellar completely separates the suprapatellar bursa from the knee joint. Occa-
border (Fig. 82.16). The bursa is an extension of the joint cavity. The sionally, a septum persists, either in its entirety or perforated by a small
attachment of articularis genus to its proximal aspect prevents the bursa peripheral opening.
from collapsing into the joint. Alongside the patella, the membrane The infrapatellar fat pad is the largest part of a circumferential extra-
extends beneath the aponeuroses of the vasti, especially under vastus synovial fatty ring that extends around the patellar margins (Newell
medialis. It extends proximally a hand’s breadth above the superior pole 1991).
of the patella. Distal to the patella, the synovial membrane is separated At the sides of the joint, the synovial membrane descends from the
from the patellar ligament by an infrapatellar fat pad. Where it lies femur and lines the capsule as far as the menisci, whose surfaces have
beneath the fat pad, the membrane projects into the joint as two fringes, no synovial covering. Posterior to the lateral meniscus, the membrane
alar folds, which bear villi. The folds converge posteriorly to form a forms a subpopliteal recess between a groove on the meniscal surface
single infrapatellar fold or plica (ligamentum mucosum), which curves and the tendon of popliteus, which may connect with the superior
posteriorly to its attachment in the femoral intercondylar fossa (Fig. tibiofibular joint. The relationship of the synovial membrane to the
82.17). This fold may be a vestige of the inferior boundary of an origi- cruciate ligaments is described above.
nally separate femoropatellar joint. The extent of the infrapatellar plica
ranges from a thin cord to a complete sheet that can obstruct the Bursae
passage of instruments during knee arthroscopy. When substantial, it Numerous bursae are associated with the knee. Anteriorly, there is a
has been mistaken for the anterior cruciate ligament, which is directly large subcutaneous prepatellar bursa between the lower half of the
posterior to it. The medial plica extends in the midline anteriorly from patella and skin; a small, deep infrapatellar bursa between the tibia and
the medial alar fold medially to the suprapatellar bursa. Occasionally, patellar ligament; a subcutaneous infrapatellar bursa between the distal | 1,909 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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part of the tibial tuberosity and skin; and a large suprapatellar bursa, extension, i.e. they are obligatory. They can also be adjunct and inde-
which is the superior extension of the knee joint cavity (see Fig. 82.16). pendent, i.e. voluntary, and are best demonstrated with the knee semi-
Posterolaterally, there are bursae between the lateral head of gastrocne- flexed. The degree of axial rotation therefore varies with flexion and
mius (lateral subtendinous bursa of gastrocnemius) and the joint extension.
capsule (this bursa is sometimes continuous with the joint cavity); the The range of extension is 5–10° beyond the ‘straight position’. Active
fibular collateral ligament and the tendon of biceps femoris; the fibular flexion is approximately 120° with the hip extended, 140° when it is
collateral ligament and the tendon of popliteus; and the tendon of flexed, and 160° when aided by a passive element, e.g. sitting on the
popliteus and the lateral femoral condyle, which is usually an extension heels. Voluntary rotation is 60–70° but conjunct rotation only 20°.
of the synovial cavity of the joint. The last two bursae may communicate Conjunct medial rotation of the femur on the tibia in the later stages
with each other. of extension is part of a ‘locking’ mechanism, the so-called ‘screw-home
Medially, the arrangement of the bursae is complex. The bursa movement’, which is an asset when the fully extended knees are sub-
between the medial head of gastrocnemius and the fibrous capsule is jected to strain. Full extension results in the close-packed position, with
prolonged between the medial tendon of gastrocnemius and the tendon maximal spiralization and tightening of the ligaments. The roles of the
of semimembranosus (the semimembranosus bursa), and usually com- articular surfaces, musculature and ligaments in generating conjunct
municates with the joint. The bursa between the tendon of semimem- rotations remain controversial (Girgis et al 1975, Rajendran 1985) but
branosus and the medial tibial condyle and the medial head of the following points can be made. The lateral combined meniscotibial
gastrocnemius may communicate with this bursa. The anserine bursa ‘receiving surface’ is smaller, more circular and more deeply concave.
is located between the tibial collateral ligament and the tendons of Since the articular surface is virtually convex in sagittal section, the
sartorius, gracilis and semitendinosus. Bursae that vary in both number depth of the receiving surface is largely due to the presence of the lateral
and position lie deep to the tibial collateral ligament between the joint meniscus. The lateral femoral articular surface is also smaller. Conse-
capsule, femur, medial meniscus, tibia or tendon of semimembranosus. quently, the lateral femoral condyle approaches full congruence with
Occasionally, there may be a bursa between the tendons of semimem- the opposed surface some 30° before full extension (well before the
branosus and semitendinosus. Posteriorly, bursae associated with the medial condyle). Simple extension cannot continue, but medial rota-
knee are variable. tion of the femur occurs on a vertical axis through its head and medial
The clinically important bursae are the anterior group, the anserine condyle; the medial femoral condyle moves very little in the sagittal
bursa and the semimembranosus bursa. Inflammation of the subcuta- plane and is stabilized by the ‘upslope’ of the anterior half of the medial
neous prepatellar bursa and infrapatellar bursa are referred to colloqui- tibia, while rotation of the lateral femoral condyle and meniscus brings
ally as ‘housemaid’s knee’ and ‘clergyman’s knee’, respectively. The the anterior horn of the latter on to the anterior ‘downslope’ of the
anserine bursa can become inflamed, especially in athletes. In adults, lateral tibial condyle. Rotation and extension follow simultaneously
bursal inflammation producing a popliteal fossa swelling commonly and smoothly until final close packing of both condyles is accom-
occurs secondary to degeneration within the knee joint; regardless plished. At the beginning of flexion from full extension (with the foot
of its size and position, it almost always arises from the plane fixed), lateral femoral rotation occurs, which ‘unlocks’ the joint. While
between semimembranosus and the tendon of the medial head of joint surfaces and many ligaments are involved, electromyographic evi-
gastrocnemius. dence reveals that contraction of popliteus is important, and that it
pulls down and backwards on the lateral femoral condyle, lateral to the
Relations and ‘at risk’ structures axis of femoral rotation. It also retracts the posterior horn during lateral
rotation and continuing flexion, via its attachment to the lateral menis-
cus, and so prevents traumatic compression.
The tendon of quadriceps femoris (which encloses and is attached to
Any position of extension adopted is a balance between forces
the non-articular surfaces of the patella), the patellar ligament, tendi-
(torque) extending the joint and passive mechanisms resisting them.
nous expansions from vasti medialis and lateralis (which extend over
The range near to close packing is functionally important. In symmetri-
the anteromedial and anterolateral aspects of the capsule, respectively),
cal standing, the line of the body’s weight is anterior to the transverse
and the patellar retinacula all lie anterior to the knee joint. Postero-
axes of the knee joints, but the passive mechanisms noted above pre-
medially are sartorius and the tendon of gracilis (which lies along its
serve posture with minimal muscular effort (Joseph 1960). Active con-
posterior border); both descend across the joint. Posterolaterally, the
traction of quadriceps femoris and a close-packed position only occurs
tendon of biceps femoris and the common fibular nerve (which lies
in asymmetrical postures, e.g. in leaning forward, during heavy loading,
medial to the tendon) are in contact with the capsule, and thereby
or when powerful thrust is needed.
separated from the tendon of popliteus. Posteriorly, the popliteal artery
In knee extension, parts of the cruciate ligaments, the tibial and
and associated lymph nodes lie posterior to the oblique popliteal liga-
fibular collateral ligaments, the posterior capsular region, the oblique
ment; the popliteal vein is posteromedial or medial, and the tibial nerve
popliteal ligament, skin and fasciae are all taut. Passive and sometimes
is posterior to both. The nerve and vessels are overlapped by both heads
active tension exists in the posterior thigh muscles and gastrocnemius,
of gastrocnemius and laterally by plantaris. Gastrocnemius contacts the
and the anterior part of the medial meniscus is compressed between
capsules on either side of the vessels. Semimembranosus lies between
the femoral and tibial condyles. During extension, the patellar ligament
the capsule and semitendinosus, medial to the medial head of
is tightened by quadriceps femoris but is relaxed in the erect attitude.
gastrocnemius.
When the knee flexes, the fibular collateral ligament and the posterior
part of the tibial collateral ligament relax but the cruciate ligaments and
Movements at the knee
the anterior part of the tibial collateral ligament remain taut; the pos-
terior parts of the menisci are compressed between the femoral and
Movements at the knee are customarily described as flexion, extension, tibial condyles. Flexion is checked by quadriceps femoris, anterior parts
medial (internal) and lateral (external) rotation. Flexion and extension of the knee joint capsule, posterior cruciate ligament and compression
differ from true hingeing, in that the articular surface profiles of the of soft tissues behind the knee. In extreme passive flexion, contact of
femoral and tibial articular surfaces produce a variably placed axis of the calf with the thigh may be the limiting factor and parts of both
rotation during the flexion arc, and when the foot is fixed, flexion cruciate ligaments are also taut. In addition to conjunct rotation with
entails corresponding conjunct (coupled) lateral rotation. These con- terminal extension or initial flexion, relaxed collateral ligaments also
junct rotations are a product of the complex geometry of the articular allow independent medial and lateral rotation (adjunct rotation) when
surfaces and, to an extent, the disposition of the associated ligaments. the joint is flexed.
There is differential motion in the medial and lateral tibiofemoral
compartments. Laterally, there is considerable displacement of the Accessory movements
femur on the tibia, with rolling as well as sliding at the joint surface. Wider rotation can be obtained by passive movements when the knee
In contrast, medially, for most of the flexion arc there is minimal rela- is semi-flexed. To a limited extent, the tibia can also be translated back-
tive motion of the femur and tibia, and the motion almost exclusively wards and forwards on the femur. Abduction and adduction are pre-
involves one joint surface sliding on the other. In full flexion, the lateral vented in full extension by the collateral ligaments and secondary
femoral condyle is close to posterior subluxation off the lateral tibial restraints such as the cruciate ligaments. With the knee slightly flexed,
articular surface. Medially, significant posterior femoral displacement limited adduction and abduction are possible, both passive and active.
only occurs when flexion exceeds 120°. The menisci move with the Slight separation of the femur and tibia can be achieved by strong trac-
femoral condyles, the anterior horns more than the posterior, and the tion on the leg with countertraction applied to the thigh.
lateral meniscus considerably more than the medial. Physiological knee joint laxity may occur during puberty. Increased
The axial rotations have a smaller range than the arc of flexion and knee joint flexibility is seen more frequently in adolescent girls than
extension. These rotations are conjunct, and integral with flexion and boys. There is an inverse relationship between Tanner stage and the | 1,910 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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degree of laxity with a progressive decrease of sagittal laxity at the onset generated by activities such as running, the patella has the thickest
of Tanner stage 2 (Falciglia et al 2009). articular cartilage in the body.
Muscles producing movements
Flexion Flexion is produced by biceps femoris, semitendinosus and BIOMECHANICS OF THE KNEE
semimembranosus, assisted by gracilis, sartorius and popliteus. With
the foot stationary, gastrocnemius and plantaris also assist (see Fig. The knee joint is a complex synovial joint consisting of the tibiofemoral
82.3). and patellofemoral articulations. It functions to control the centre of
body mass and posture in the activities of daily living. This necessitates
Extension Extension is produced by quadriceps femoris, assisted by a large range of movement in three dimensions coupled with the ability
tensor fasciae latae. to withstand high forces. These conflicting parameters of mobility and
stability are only achieved by the interactions between the articular
Medial rotation of the flexed leg Medial rotation of the flexed surfaces, the passive stabilizers and the muscles that cross the joint.
leg is produced by popliteus, semimembranosus and semitendinosus, The relatively incongruent nature of the joint surfaces makes the
assisted by sartorius and gracilis. knee joint inherently mobile. In addition, because it acts as a pivot
between the longest bones in the body, and is subjected to considerable
Lateral rotation of the flexed leg Lateral rotation of the flexed loads in locomotion, the joint is also potentially at risk of injury if any
leg is produced by biceps femoris. of the multiple factors providing joint stability are compromised. The
long bones may act as levers, increasing the stresses on the stabilizing
Patellofemoral joint The alignment of the femoral and tibial shafts ligaments.
is such that the pull of quadriceps femoris on the patella imparts a force
on the patella that is directed both superiorly and laterally. The static
bony factors that counter this tendency to move laterally are the congru- KNEE JOINT KINEMATICS
ity of the patellofemoral joint and the buttressing effect of the larger
lateral part of the patellar surface of the femur, which, clinically, is often The surfaces of the tibia and femur are not as conforming as those of
referred to as the trochlear groove. Instability of the patella may result the relatively congruent hip joint. Although this variation in geometry
if the patella is small or if the patellar surface of the femur is too permits motion to occur in six degrees of freedom (Fig. 82.18), the
shallow. The static ligamentous factors are the medial patellofemoral primary motion of the knee occurs in the sagittal plane, and a relatively
ligament and medial patellar retinaculum. minor degree of movement occurs in the transverse plane. The knee
Dynamic neuromuscular control is important. The most distal part joint may therefore be described simplistically as a modified hinge joint
of vastus medialis (vastus medialis obliquus) consists of transverse allowing flexion–extension and a measure of rotatory motion. Knee
fibres that are attached directly to the medial edge of the patella: these motion is normally defined as starting from 0° (the neutral position),
pull the patella medially, countering the tendency to move laterally. when the tibia and femur are in line in the sagittal plane. Biomechani-
This is the muscle that is preferentially strengthened in a physical cally, it is important that the knee reaches the neutral position in exten-
therapy programme aimed at treating patellofemoral conditions often sion because that allows the leg to support the body weight like a simple
associated with patella tracking problems such as those seen in growing strut when the subject is standing still. When the subject is standing
adolescents. upright, if the knee is flexed, the vertical line of action of the body
weight passes posterior to the centre of rotation of the knee, tending to
Tibiofemoral joint The tibiofemoral joint surfaces are inherently cause the body to tilt posteriorly. To counterbalance this, continuous
mobile, especially laterally. Medially, some stability is afforded by the quadriceps femoris contraction is required, causing expenditure of
relatively concave tibial surface and the relatively fixed posterior horn energy.
of the medial meniscus. Both medially and laterally the menisci are
helpful, particularly as they move with the femoral condyles. Ligaments Anterior/posterior translation Medial/lateral shift Compression/distraction
play a major role in constraining mobility because they bind the bones
in positions of extreme stress and also provide proprioceptive feedback,
aiding coordination of stabilizing muscle activity. To take a somewhat
‘two-dimensional’ view, the tibial and fibular collateral ligaments may
be considered as sensors (resistors) of valgus and varus forces on the
knee, respectively, and the anterior and posterior cruciate ligaments as
sensors (resistors) of anterior and posterior tibial translation, respec-
tively. However, in reality the situation is more complex than this. The
stresses are rarely applied in orthogonal planes and so a combination
of forces, especially rotational, is involved. Moreover, many structures
other than the collateral and cruciate ligaments are involved in stabiliz-
ing the joint. The ‘posterolateral corner’, which resists tibial lateral
rotation, consists of the popliteofibular, fabellofibular, arcuate and
fibular collateral ligaments and iliotibial tract, together with popliteus,
the lateral head of gastrocnemius and biceps femoris. The ‘postero-
medial corner’, which resists tibial rotation, consists of the posterior
oblique portion of the superficial part of the tibial collateral ligament, Abduction/adduction Flexion/extension Medial/lateral rotation
the capsule including the oblique popliteal ligament and semimem-
branosus. Since stresses are often a combination of force plus rotation,
structures usually operate together rather than in isolation.
Loading at the knee
During level walking, the force across the tibiofemoral joint for most
of the cycle is between two and four times body weight, and can be
more. In contrast, the force across the patellofemoral joint is no more
than 50% of body weight. Peak force transmission across the joint
increases sequentially as the menisci, articular cartilage and subchon-
dral bone are damaged or removed. Walking up or down stairs has little
influence on tibiofemoral forces, but significantly increases patellofem-
oral forces to two (walking up) or three (walking down) times body
weight, reflecting the changed angle of the tendon of quadriceps femoris
and patellar ligament during flexion. There are two mechanisms for
ameliorating forces transmitted across the patella: the extensor lever
arm is lengthened as the axis of rotation moves posteriorly during
flexion, and the contact area between the patella and femur almost Fig. 82.18 The knee joint motion in three dimensions, described using six
triples between 30° and 90°. To cope with the potential large forces independent variables (degrees of freedom). | 1,911 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Active knee flexion leads to approximately 130° flexion. The active the geometry and tighten the soft tissues, thereby maintaining the knee
motion is limited by apposition of the soft tissue masses (posterior in a stable position prior to the impact load of weight-bearing. The knee
thigh and calf). Passive flexion may reach 160°. This is required in acts as one link in a chain of limb segments, and this screw-home relates
people who habitually kneel as part of daily life, and is a challenge for to rotation of both the foot and hip. When the foot is swung forwards
designers of knee prostheses. It can be observed that such deep flexion for heel strike, the pelvis rotates so that the hip is moved forwards, a
is often accompanied by tibial medial rotation, so that, when the movement that entails lateral rotation of the hip. During stance, the
subject is kneeling, the buttocks can rest on the feet. This movement femur is medially rotated against the locked knee. Tibial lateral rotation
carries the lateral tibial plateau anteriorly, so that it does not engage also causes inversion of the foot at the subtalar joint, raising the arch
with the femoral lateral condyle in deep knee flexion. The femoral and locking the structure of the foot. The knee flexion that occurs after
condyle passes posteriorly and rides over the horn of the lateral the impact on the ground allows the tibia to rotate medially so that the
meniscus. foot everts, softening its structure and allowing it to deform and absorb
The most frequently employed knee movement occurs when walking energy. Conversely, towards toe-off, the knee extends, rotating the tibia
(Fig. 82.19). When the leg is swinging past the supporting leg, the knee laterally, so the foot is again a rigid lever with which to push the body
must be flexed in order to avoid dragging the toes on the ground; this forwards.
requires approximately 67° knee flexion. When the swinging leg
Articular kinematics
approaches the first contact with the ground, the knee extends, to move
the foot forwards for heel strike. If the knee remained extended, this We now consider knee motion at a smaller scale, within the joint. This,
would then cause the body to move in a circular arc, centred at the of course, is difficult to separate from the actions of the ligaments that
ankle, causing the centre of gravity to move upwards and then back act as passive restraints to tibiofemoral joint movements, and are dis-
down again, leading to more energy expenditure. It would also increase cussed below.
the forces on the knee because the leg would act more like a rigid strut, Sagittal sections of the knee reveal that the arcs of the femoral con-
unable to dissipate the impact forces when the foot hit the ground. All dyles are much longer than the anterior–posterior length of the tibial
these problems are overcome by flexing the knee 15° in the mid-stance plateau. This means that if the knee flexed with a purely rolling motion,
phase; the centre of gravity of the body can move forwards at approxi- then the femur would roll off the back of the tibia long before the knee
mately constant height, and the impact energy is absorbed by stretching reaches full flexion (see Fig. 82.20). This does not happen because the
quadriceps femoris (see Fig. 82.19). femur slides anteriorly at the same time as it rolls posteriorly, and thus
Tibial medial–lateral rotation also occurs during gait: the tibia remains in correct articulation. If the knee were to possess a fully con-
rotates laterally during terminal extension, a phenomenon known as forming roller-in-trough geometry, as in the humero-ulnar joint, then
‘screw-home’ (Fig. 82.20). It is surmised that this rotation helps to lock flexion would occur by pure sliding movement between the joint
Fig. 82.19 Knee flexion–extension motion during gait.
)º(
noixelf
tnioj
eenK
Contralateral
Heel strike heel strike Toe-off
60
30
20
0
0 10 20 30 40 50 60 70 80 90 100
% Gait cycle
A B C Fig. 82.20 Knee joint kinematics during gait:
rolling and sliding (flexion, anterior translation).
Rolling
F F
F
1
2 Anterior cruciate
3 2 1 3 2 1 3 ligament
Tension
Sliding
2 1 2 1 2 1
T T T
Extension: Early flexion: Deeper flexion:
Central contact Posterior rolling. Anterior cruciate
of femur on to tibia Contact now ligament prevents
(F1 on to T1) moves back to the femur from rolling
F2 on to T2 back further, so now
it slides on the tibia.
F3 moves on to T2 | 1,912 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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surfaces. This conformity is not possible at the knee because it would anterior horns of the menisci, and the femoral contact is now solely on
inhibit the tibial medial–lateral rotation that is needed during the posterior horns in the flexed knee. This, combined with the large
locomotion. joint forces that are generated when arising from a seated position,
In the locked, fully extended knee, the anterodistal femoral articular explains why there are often spontaneous tears of the posterior horns
surfaces press on to the anterior horns of the menisci. This tends to in older patients, when standing up from a squatting position.
cause the femur to slide posteriorly, tensing the anterior cruciate liga- The load-carrying mode of the menisci is shown in Figure 82.23.
ment and slackening the posterior cruciate ligament. With knee flexion, When the femoral condyle presses down on the meniscus, it tends to
the femur lifts off the anterior horns of the menisci, leading to contact squeeze the meniscus out of the joint because of its tapered cross-
between the smaller radii of the posterior parts of the femoral condyles section. This causes the diameter of the circular shape of the meniscus
and the tibial plateau plus the posterior horns of the menisci. This (and therefore the meniscal circumference) to increase. This is resisted
means that the centre of contact moves posteriorly in early knee flexion. by ‘hoop tension’ in strong fibres that pass around the periphery of the
After this, the femoral condyles have approximately circular sagittal meniscus, and transmit the tension to the tibial plateau via strong
sections. The femur is now prevented from rolling back any further by insertional ligaments. As the tissue is adapted to resist hoop stresses, it
tension in the anterior cruciate ligament. has much greater hoop strength (approximately 100 MPa) than radial
strength (approximately 3 MPa), which explains why bucket handle
Articular mechanics
tears occur. It also explains why a circumferential tear does not have
The combined effect of the external and internal loads on the knee is such a serious effect on meniscal function because the circumferential
to impose considerable forces on the articular cartilage. This may be fibres can still transmit the loads, whereas a radial tear breaks the load-
analysed as a vertical (compressive) component and a horizontal (shear carrying fibres.
or friction) component. The friction component is a combination of
the compressive force and the friction characteristics of the joint Friction
surfaces. The knee acts as a bearing that transmits forces and movements between
the limb segments. Load-bearing synovial joints move with remarkably
Compression
little friction and their surfaces must withstand many millions of impact
The compressive force is distributed over an area to produce a contact loads, which tend to cause fatigue failure and breakdown of the
pressure (contact stress). The contact pressure is, therefore, dependent surfaces.
on the area of contact as well as the load itself. Fully conforming articu- During walking, every step involves phases of action that vary the
lar surface geometry would allow the greatest area of contact, and thus loading and velocity conditions at the knee joint. A variety of lubrica-
would minimize contact pressure; however, this is not present in the tion mechanisms normally prevent joint surface damage. Thus, in the
knee. The medial compartment of the knee is semi-conforming with a swing phase, when the foot is off the ground, the joint surfaces are
convex femoral condyle articulating over a concave medial tibial
plateau. The lateral compartment has less conformity; the lateral tibial
plateau is flat or slightly convex in sagittal sections. These different
shapes reflect the differential movement of the medial and lateral com-
partments. In normal movement, the screw-home rotation of the tibia
occurs about a medial axis, which means that most of the rotation of
the tibia is due to an anterior–posterior translation of the lateral com-
partment (Fig. 82.21).
In order to maintain some degree of conformity, and also to mini-
mize contact pressure between the femur and tibia, the menisci are
wedge-shaped in cross-section, thereby increasing the area over which
the compressive force on the knee is distributed. In the absence of the
menisci, the load is carried by a much smaller area of cartilage, resulting
in higher contact stresses on the articular cartilage. This helps to explain
the prevalence of osteoarthrosis following meniscectomy (Fig. 82.22).
The menisci are most firmly attached at the intercondylar eminence
of the tibia, which means that they can translate anteriorly and pos-
teriorly to ‘follow’ the femoral rollback. The lateral meniscus is more
mobile because it is attached to the capsule less tightly than the medial
meniscus. The anterior–posterior movement of the menisci is approxi-
mately half the magnitude of the anterior–posterior movement of the
femur, suggesting that the conformity of the joint changes during
flexion of the knee joint.
The distal aspect of the femur, resting on the menisci in the extended
knee, has a large radius of curvature and thus fits against the entire area
of the menisci. However, as the knee flexes, the smaller radii of the
posterior parts of the femoral condyles cause the femur to lift off the
Fig. 82.22 The function of the menisci in increasing articular conformity,
Medial compartment Lateral compartment with increased peak pressure before and after meniscectomy.
Medial pivot in concave
tibial plateau
Mobile lateral
compartment
Concave tibial plateau Convex/flat tibial plateau
(congruent) (incongruent)
Fig. 82.21 The shape of the articular surfaces providing mobility of the Fig. 82.23 The load-carrying mode of the menisci. Conversion of axial
lateral compartment. load into meniscal hoop stresses. | 1,913 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Knee
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Swing phase Heel strike Stance phase Toe-off
Muscle Muscle
tension tension
Flexion/
extension
Rapid
motion
Impact Body weight
Load
Femur
Fluid
trapped
Tibia
Fluid film Squeeze film: Hydrodynamic lubrication: Squeeze film with protein
fluid squeezed out, cartilage surface deforms, boundary lubricant
microscopic separation trapping fluid film
remains
Fig. 82.24 The different modes of knee joint motion and lubrication when walking.
loaded lightly, and have high relative velocity while the knee flexes and displacement and allow the joint to maintain its stability. Disruption
extends. This allows the synovial fluid to separate the surfaces, giving of any of these passive restraints may cause a mechanical instability,
fluid film lubrication, with very low friction and no wear (Fig. 82.24). which is an abnormally increased displacement due to an applied force
At the time of heel strike, a large impact load acts to compress the (in biomechanical terms this is called excess laxity).
surfaces together. At a microscopic level, the surfaces do not come into
Primary and secondary restraints
contact because of the squeeze-film effect: in essence, the impact occurs
so rapidly (less than 0.1 sec) that the synovial fluid cannot all be On testing the laxity in any of the degrees of freedom of the joint (e.g.
squeezed out of the joint space because of its viscosity and the narrow- in the anterior drawer test, a bedside clinical test in which the subject
ness of the space. In the mid-stance phase, the flexion–extension motion is placed in the supine position with the knee to be tested flexed to
again entrains the synovial fluid in between the joint surfaces, prod- 80–90° before passive forward traction is applied to the tibia), there
ucing what is known as a hydrodynamic effect: the fluid is trapped are usually combinations of ligaments that are tensed. Some of these
between the surfaces by the motion and therefore it acts to separate are better aligned to resist the applied load or displacement. These are
them. Finally, when the foot is pushing off the body weight, there is termed primary restraints, and are exemplified by the cruciate ligaments
little motion and the thin fluid film diminishes under the compressive and the tibial and fibular collateral ligaments. Secondary restraints are
load. If the squeeze-film effect were insufficient, then the joint surfaces less well aligned but still have a significant restraining effect. These are
would come into direct contact were it not for the fact that the synovial exemplified by the menisci and by the meniscofemoral ligaments. In
fluid contains large protein molecules that are trapped on the cartilage the example in Figure 82.25, the anterior cruciate ligament is well
surfaces when the fluid is expelled. This molecular layer acts as a bound- aligned to resist the applied anterior force. With an absent anterior
ary lubricant, protecting the cartilage in the same way that grease pro- cruciate ligament, the tibial collateral ligament can resist the applied
tects a synthetic bearing. force; however, it does so by being loaded to a much higher level than
Many aspects of the arthritic breakdown of the cartilage can be the original loading on the anterior cruciate ligament. The size of the
explained on the basis of lubrication biomechanics. Thus, in joints lines in the vector diagram demonstrate this principle: although joint
affected by osteoarthrosis, synovial fluid is known to have a lower vis- laxity may remain normal initially following rupture of a primary
cosity than that in normal joints. The viscosity is lower still in joints restraint, it may subsequently result in the overload of a secondary
afflicted with rheumatoid arthritis and is unable to prevent attritional restraint and, ultimately, in further soft tissue failure.
damage to the cartilage surfaces. The patellofemoral joint is most heavily loaded during weight-
bearing activities when the knee is flexed. Analyses of rising from a chair
have predicted that the patellar ligament tension at 90° of knee flexion
SOFT TISSUE MECHANICS may be greater than the tibiofemoral joint, which is loaded at the same
time (Amis and Farahmand 1996).
The knee joint relies on active (musculotendinous) and passive (liga- In the frontal plane, quadriceps femoris and the patellar ligament
mentous) restraints to maintain its stability. The muscles provide the tensions combine to cause a lateralizing force vector termed the Q-angle
loading to move the joint: quadriceps femoris, hamstrings and gastroc- effect. The Q angle is defined as the difference between the resultant
nemius control both flexion/extension and medial–lateral rotation. force vector of quadriceps femoris, which is normally parallel to the
However, they also cause anterior–posterior shear forces that are resisted femoral shaft, and the patellar ligament (Fig. 82.26). Clinically, the Q
primarily by the cruciate ligaments. This tethering effect is critical in angle is changed by the position of hip rotation, tibial rotation and
allowing the joint to move physiologically, maintaining congruency quadriceps femoris tension. The clinical Q angle is 12–15° (males) and
and stability. 15–18° (females), which means that there is a greater lateralizing force
The passive stabilizers of the joint act by resisting unwanted displace- vector on the patellofemoral joint in females. Contraction of quadriceps
ments between the bones. This may be to control the path of motion femoris, therefore, tends to displace the patella laterally, which is
or to limit the range of motion. When the muscles or some other exter- resisted by the geometry of the joint and by the ligaments. Vastus
nal force (due to body weight or impact) cause the bones to displace, medialis obliquus acts medially and posteriorly as much as it acts
the ligaments are stretched, and so develop tensile forces that resist the proximally, and so its tension helps to resist the Q-angle effect. | 1,914 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Vascular supply and lymphatic drainage
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Popliteus is attached to the medial aspect of the head of the fibula
by the popliteofibular ligament, which passes laterally and inferiorly
from the popliteus tendon in a sheet of tissue that is normally about
2 cm2. This ligament is the single most important stabilizer of the pos-
terolateral region of the knee and resists lateral rotation of the tibia on
the femur. Failure to recognize and reconstruct damage to this ligament
Applied force
and to the related ligamentous structures is the most common reason
for a poor result from an otherwise well-performed operation for repair
ACL vector of ruptured cruciate ligaments.
Fleshy fibres expand from the inferior limit of the tendon to form a
Anterior cruciate ligament (ACL)
somewhat triangular muscle that descends medially to be inserted into
the medial two-thirds of the triangular area above the soleal line on the
posterior surface of the tibia, and into the tendinous expansion that
covers its surface.
An additional head may arise from the sesamoid bone in the lateral
head of gastrocnemius. Very rarely, two other muscles may be found
deeply situated behind the knee. Popliteus minor runs from the pos-
terior surface of the lateral tibial condyle, medial to plantaris, to the
oblique popliteal ligament. Peroneotibialis runs deep to popliteus
from the medial side of the fibular head to the upper end of the
soleal line.
Relations Popliteus is covered posteriorly by a dense aponeurotic
expansion, which is largely derived from the tendon of semimembrano-
Applied force
sus. Gastrocnemius, plantaris, the popliteal vessels and the tibial nerve
all lie posterior to the expansion. The popliteal tendon is intracapsular
and is deep to the fibular collateral ligament and the tendon of biceps
Superficial tibial femoris. It is invested on its deep surface by synovial membrane, and
collateral ligament (sTCL)
grooves the posterior border of the lateral meniscus and the adjoining
part of the tibia before it emerges inferior to the posterior band of the
sTCL vector arcuate ligament. This region is called the ‘popliteus hiatus’; the lateral
meniscus has no peripheral bony attachment here and is therefore
rather mobile.
Vascular supply The arterial supply of popliteus is derived mainly
Fig. 82.25 Primary and secondary restraints to anteroposterior forces. from the inferior medial and lateral genicular arteries. The latter may
The example shows the anterior cruciate ligament (ACL) and superficial cross either superficial or deep to the muscle. There are additional con-
part of the tibial collateral ligament (sTCL). tributions from the nutrient artery of the tibia (from the posterior tibial
artery), the proximal part of the posterior tibial artery, and the posterior
tibial recurrent artery.
A Q B
Q
Innervation Popliteus is innervated by a branch of the tibial nerve
(L4, 5 and S1), which winds around the distal border of popliteus and
enters the anterior surface of the muscle; this nerve also innervates
the superior tibiofibular joint and the interosseous membrane of
PF
the leg.
PL
PF
Actions Popliteus rotates the tibia medially on the femur or, when
PL the tibia is fixed, rotates the femur laterally on the tibia. It is usually
regarded as the muscle that ‘unlocks’ the joint at the beginning of
flexion of the fully extended knee; electromyography supports this view.
Its connection with the arcuate popliteal ligament, fibrous capsule and
PL lateral meniscus has led to the suggestion that popliteus may retract the
Q
posterior horn of the lateral meniscus during lateral rotation of the
Q PL PL femur and flexion of the knee joint, thus protecting the meniscus from
PL being crushed between the femur and the tibia during these move-
ments. The muscle is markedly active in crouching, perhaps to provide
PL = Patellar ligament force PF = Patellofemoral joint reaction force Q = Quadriceps
femoris traction force stability as the tibia rotates medially during flexion of the knee. However,
the main function is likely to be provision of dynamic stability to the
Fig. 82.26 The patellofemoral joint force with knee extension (A) and with
posterolateral part of the knee by preventing excessive lateral rotation
90° of knee flexion (B).
of the tibia, partly by its direct action, but more significantly by tensing
the popliteofibular ligament.
MUSCLES
VASCULAR SUPPLY AND LYMPHATIC DRAINAGE
The majority of muscles that act on the knee joint are described in either
ARTERIES
Chapter 80 (quadriceps femoris, semimembranosus, biceps femoris,
semitendinosus, articularis genus) or on page 1409 (gastrocnemius).
Popliteus is described below. There is an intricate arterial anastomosis around the patella and the
femoral and tibial condyles (see Fig. 78.4). A superficial arterial network
Popliteus spreads between the fascia and skin around the patella and in the fat
Attachments Popliteus is a flat muscle that forms the floor of the deep to the patellar ligament. A deep arterial network lies on the femur
lower part of the popliteal fossa (see Figs 82.12A, 83.4B, 83.9A). It arises and tibia near the adjoining articular surfaces, and supplies the bone,
within the capsule of the knee joint by a strong tendon, 2.5 cm long, articular capsule, synovial membrane and cruciate ligaments (see Fig.
which is attached to a depression at the anterior end of the groove 82.1). The vessels involved are the superior, middle and inferior genicu-
(groove for popliteus) on the lateral aspect of the lateral condyle of the lar branches of the popliteal artery; descending genicular branches of
femur. Medially, this tendon is joined by collagenous fibres arising from the femoral artery and descending branch of the lateral circumflex
the arcuate popliteal ligament; the fibrous capsule adjacent to the lateral femoral artery; circumflex fibular artery; and anterior and posterior
meniscus; and the outer margin of the meniscus. tibial recurrent arteries. For details, consult Scapinelli (1968). | 1,915 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Knee
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Variations in the arterial anatomy of the lower limb proximal to the medial head of gastrocnemius and deep to the tendon
Most anatomical variations in the arterial pattern of the lower limb of adductor magnus. It divides into a branch to vastus medialis that
arteries cause no symptoms. They are usually incidental findings in the anastomoses with the descending genicular and inferior medial genicu-
dissection room, or may come to light in the course of angiographic lar arteries, and a branch that ramifies on the femur and anastomoses
examination. Some variations in vascular anatomy may be symptomatic with the superior lateral genicular artery. Its size varies inversely with
and may necessitate surgical correction; other variations, while asymp- that of the descending genicular artery. The superior lateral genicular
tomatic, may influence technical considerations during vascular surgical artery passes under the tendon of biceps femoris, pierces the lateral
procedures. intermuscular septum and divides into superficial and deep branches.
Anatomical variations of the femoral, profunda femoris, anterior The superficial branch supplies vastus lateralis and anastomoses with
and posterior tibial and fibular arteries have been described elsewhere the descending branch of the lateral circumflex femoral and inferior
in this Section. lateral genicular arteries, while the deep branch anastomoses with the
superior medial genicular artery, forming an anterior arch across the
Popliteal artery femur with the descending genicular artery. The superficial branch is
vulnerable if the lateral patellar retinaculum is divided surgically.
The popliteal artery is the continuation of the femoral artery and crosses Middle genicular artery The middle genicular artery is small. It
the popliteal fossa (see Figs 82.2, 82.4). It descends laterally from the
arises from the popliteal artery near the midpoint of the posterior aspect
opening in adductor magnus to the femoral intercondylar fossa, inclin-
of the knee joint. It pierces the oblique popliteal ligament to supply the
ing obliquely to the distal border of popliteus, where it divides into the
cruciate ligaments and synovial membrane.
anterior and posterior tibial arteries. This division usually occurs at
the proximal end of the interosseous space between the wide tibial
Inferior genicular arteries The inferior medial and lateral genicu-
metaphysis and the slender fibular metaphysis. The artery is relatively
lar arteries arise from the popliteal artery deep to gastrocnemius. The
tethered at the adductor hiatus and again distally by the fascia related
inferior medial genicular artery is deep to the medial head of gastroc-
to soleus, and is therefore susceptible to damage following knee
nemius. It descends along the proximal margin of popliteus, which it
injuries, e.g. dislocation. Aneurysms of the popliteal artery are not
supplies; passes inferior to the medial tibial condyle, under the tibial
uncommon.
collateral ligament; and then ascends anteromedial to the knee joint at
the anterior border of the tibial collateral ligament. It supplies the joint
Variations in the popliteal artery
and the tibia, and anastomoses with the inferior lateral and superior
The popliteal artery may occasionally bifurcate more superiorly and
medial genicular arteries and with the anterior tibial recurrent artery
divide into its terminal branches proximal to popliteus, or it may tri-
and saphenous branch of the descending genicular artery. The inferior
furcate into anterior and posterior tibial and fibular arteries. Either the
lateral genicular artery runs laterally across popliteus and forwards over
anterior tibial or the posterior tibial artery may be reduced or increased
the head of the fibula to the front of the knee joint, passing under the
in size. The size of the fibular artery is usually inversely related to the
lateral head of gastrocnemius, the fibular collateral ligament and the
size of the anterior and posterior tibial arteries. Rarely, the anterior tibial
tendon of biceps femoris. Its branches anastomose with the inferior
artery is the source of the fibular artery, a variation that is almost always
medial and superior lateral genicular arteries; anterior and posterior
associated with a high bifurcation of the popliteal artery.
tibial recurrent arteries; and the circumflex fibular branch of the pos-
The popliteal and inferior gluteal arteries may be joined by a large
terior tibial artery.
anastomotic vessel; in such cases, the femoral artery is hypoplastic
(Kawashima and Sasaki 2010). When this occurs, the popliteal artery Cutaneous branches: the superficial sural arteries The
usually has an abnormal relationship to popliteus, running deep to the
superficial sural arteries are three vessels that leave the popliteal artery,
muscle before dividing into its terminal branches. The popliteal artery
or its side branches, descend between the heads of gastrocnemius and
may pass medially beneath the medial head of gastrocnemius, or may
perforate the deep fascia to supply the skin on the back of the leg. The
pass beneath an aberrant band of muscle in the popliteal fossa; in either
central or median vessel is usually larger than the medial or lateral
case, contraction of the muscles may occlude the artery – a condition
vessels, and usually accompanies the sural nerve.
that may present with claudication on exertion. The popliteal vein is
Fasciocutaneous free and pedicled flaps may be raised on the super-
usually superficial and adjacent to the artery, but it may run deep to the
ficial sural arteries.
artery, or be separated from it by a slip of muscle derived from the
medial head of gastrocnemius.
Superior muscular branches The superior muscular branches are
two or three vessels that arise proximally and pass to adductor magnus
Relations
and the posterior thigh muscles. They anastomose with the termination
Anteriorly, from proximal to distal, are fat covering the femoral pop- of the profunda femoris artery.
liteal surface, the capsule of the knee joint, and the fascia of popliteus.
Posteriorly are semimembranosus (proximally) and gastrocnemius and Sural arteries The two sural arteries are large and arise behind the
plantaris (distally). In between, the artery is separated from the skin knee joint to supply gastrocnemius, soleus and plantaris. They are used
and fasciae by fat and crossed from its lateral to its medial side by the in gastrocnemius musculocutaneous flaps.
tibial nerve and popliteal vein; the vein lies between the nerve and
artery and is adherent to the latter. Laterally are biceps femoris, the tibial
VEINS
nerve, popliteal vein and lateral femoral condyle (all proximal), and
plantaris and the lateral head of gastrocnemius (distal). Medially are
semimembranosus and the medial femoral condyle (proximal), and the The veins draining the knee correspond in name to the arteries and run
tibial nerve, popliteal vein and medial head of gastrocnemius (distally). with them; the named smaller veins drain into the popliteal and
The relations of the popliteal nodes are described below. femoral veins.
Branches (other than terminal) Popliteal vein
Genicular anastomosis There is an intricate arterial anastomosis
around the patella and femoral and tibial condyles (see Fig. 82.1). A The popliteal vein ascends through the popliteal fossa to the opening
superficial network spreads between the fascia and skin around the in adductor magnus, where it becomes the femoral vein (see Figs 78.8,
patella and in the fat deep to the patellar ligament. A deep network lies 78.9B, 80.30). Its relationship to the popliteal artery changes as the vein
on the femur and tibia near their adjoining articular surfaces, and sup- ascends: distally, it is medial to the artery; between the heads of gas-
plies the bone, articular capsule and synovial membrane. The vessels trocnemius, it is superficial (posterior) to the artery; and proximal to
involved in this anastomosis are superior medial and lateral genicular; the knee joint, it is posterolateral to the artery. Its tributaries are the
inferior medial and lateral genicular; descending genicular; descending short saphenous vein; veins corresponding to branches of the popliteal
branch of the lateral circumflex femoral; circumflex fibular; and anterior artery; and muscular veins, including a large branch from each head of
and posterior tibial recurrent arteries. gastrocnemius. There are usually four or five valves in the popliteal vein.
Superior genicular arteries The superior genicular arteries branch Long saphenous vein
from the popliteal artery, curving round proximal to both femoral
condyles to reach the anterior aspect of the knee. The superior medial The course of the long saphenous vein is described on pages
genicular artery lies under semimembranosus and semitendinosus, 1370–1371. | 1,916 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Key references
Short saphenous vein arteries. The remainder flank the popliteal vessels, receiving trunks that
accompany the anterior and posterior tibial vessels. Popliteal lymphatic
vessels ascend close to the femoral vessels to reach the deep inguinal
The short saphenous vein (small saphenous vein) begins posterior to
nodes; some may accompany the long saphenous vein to the superficial
the lateral malleolus as a continuation of the lateral marginal vein (see
inguinal nodes.
Fig. 78.9B). In the lower third of the calf, it ascends lateral to the cal-
caneal tendon, lying on the deep fascia and covered only by subcutan-
eous tissue and skin. Inclining medially to reach the midline of the calf,
INNERVATION
it penetrates the deep fascia, within which it ascends on gastrocnemius,
only emerging between the deep fascia and gastrocnemius gradually at
about the junction of the middle and proximal thirds of the calf (usually The knee joint is innervated by branches from the obturator, femoral,
well below the lower limit of the popliteal fossa). Continuing its ascent, tibial and common fibular nerves (see Fig. 78.11) (Freeman and Wyke
it passes between the heads of gastrocnemius and proceeds to its termi- 1967). The articular branch of the obturator nerve is the terminal
nation in the popliteal vein, 3–7.5 cm above the knee joint. branch of its posterior division. Muscular branches of the femoral nerve,
especially to vastus medialis, supply articular branches to the knee joint.
Tributaries Genicular branches from the tibial and common fibular nerves accom-
The short saphenous vein connects with deep veins on the dorsum of pany the genicular arteries, and those from the tibial nerve travel with
the foot, receives many cutaneous tributaries in the leg, and sends the medial and middle genicular arteries, while those from the common
several communicating branches proximally and medially to join the fibular nerve travel with the lateral genicular and anterior tibial recur-
long saphenous vein. Sometimes a communicating branch ascends rent arteries.
medially to the accessory saphenous vein: this may be the main con- The femoral and obturator nerves are described on page 1372,
tinuation of the short saphenous vein. In the leg, the short saphenous and the tibial and common fibular nerves are described on
vein lies near the sural nerve and contains 7–13 valves, with one near page 1415.
its termination. Its mode of termination is variable: it may join the long
saphenous vein in the proximal thigh or it may bifurcate, one branch Saphenous nerve
joining the long saphenous vein and the other joining the popliteal or
deep posterior femoral veins. Sometimes it drains distal to the knee in The saphenous nerve is the largest and longest cutaneous branch of the
the long saphenous or sural veins. femoral nerve and the longest nerve in the body (see Figs 78.11, 80.32).
It descends lateral to the femoral artery in the femoral triangle and
enters the adductor canal, where it crosses anterior to the artery to lie
LYMPHATIC DRAINAGE
medial to it. At the distal end of the canal, it leaves the artery and
emerges through the aponeurotic covering with the saphenous branch
Lymphatic drainage is to the popliteal nodes (see Fig. 78.10). Most of
of the descending genicular artery. As it leaves the adductor canal, it
the lymph vessels accompany the genicular arteries; some vessels from
gives off an infrapatellar branch that contributes to the peripatellar
the joint drain directly into a node between the popliteal artery and the
plexus and then pierces the fascia lata between the tendons of sartorius
posterior capsule of the knee joint.
and gracilis, becoming subcutaneous to supply the skin anterior to the
patella. It descends along the medial border of the tibia with the long
Popliteal nodes
saphenous vein and divides distally into a branch that continues along
the tibia to the ankle and a branch that passes anterior to the ankle to
There are usually six small lymph nodes embedded in the fat of the supply the skin on the medial side of the foot, often as far as the first
popliteal fossa. One, near the termination of the short saphenous vein, metatarsophalangeal joint. The saphenous nerve connects with the
drains the superficial region served by this vessel. Another lies between medial branch of the superficial fibular nerve. Near the mid-thigh, it
the popliteal artery and the posterior aspect of the knee, receiving direct provides a branch to the subsartorial plexus. The nerve may become
vessels from the knee joint and those accompanying the genicular entrapped as it leaves the adductor canal.
KEY REFERENCES
Amis AA, Dawkins GP 1991 Functional anatomy of the anterior cruciate A review of the morphological aspects of the bony knee that allow it to be
ligament. Fibre bundle actions related to ligament replacements and an efficient locking mechanism.
injuries. J Bone Joint Surg 73B:260–7.
Scapinelli R 1968 Studies on the vasculature of the human knee joint. Acta
A study of three functional components of the anterior cruciate ligament.
Anat 70:305–31.
Fibre length changes suggested that the ‘isometric point’ aimed at by some
A primary source of detail, complementing the work of Crock on the
ligament replacements lay anterior and superior to the femoral origin of the
vasculature of the bones of the lower limb.
intermediate fibre bundle and towards the roof of the intercondylar notch.
Seebacher JR, Inglis AE, Marshall JL et al 1982 The structure of the postero-
Freeman MAR, Wyke B 1967 The innervation of the knee joint: an anatomi-
lateral aspect of the knee. J Bone Joint Surg 64A:536–41.
cal and histological study in the cat. J Anat 101:505–32.
A work that established the current interpretation of the anatomy of the soft
A classic paper that investigates the gross anatomy and histology of the
tissues of the knee.
articular innervation of the knee joint. Four articular nerve endings were
classified. Tubbs RS, Michelson J, Loukas M et al 2008 The transverse genicular liga-
ment: anatomical study and review of the literature. Surg Radiol Anat
Girgis FG, Marshall JL, Al Monajem ARS 1975 The cruciate ligaments of the
30:5–9.
knee joint. Clin Orthop 106:216–31.
A cadaveric study that identified the transverse ligament of the knee in 55%
A cadaveric study that described the anterior cruciate ligament as having an
of specimens, with two specimens exhibiting a duplicated ligament.
anteromedial and posterolateral band. It suggested that the anteromedial
band was responsible for the anteroposterior drawer sign with flexion. Warren LF, Marshall JL 1979 The supporting structures and layers on the
medial side of the knee: an anatomical analysis. J Bone Joint Surg
Joseph J 1960 Man’s Posture: Electromyographic Studies. Springfield, IL:
61A:56–62.
Thomas.
A cadaveric study of the medial knee that established a three-layer pattern
Electromyography results of the muscles acting on the hip, knee and ankle
for the regional ligaments. joints, and their involvement in maintaining an upright posture.
Rajendran K 1985 Mechanism of locking at the knee joint. J Anat 143:
189–94. | 1,917 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Knee
REFERENCES
Amis AA, Dawkins GP 1991 Functional anatomy of the anterior cruciate Joseph J 1960 Man’s Posture: Electromyographic Studies. Springfield, IL:
ligament. Fibre bundle actions related to ligament replacements and Thomas.
injuries. J Bone Joint Surg 73B:260–7. Electromyography results of the muscles acting on the hip, knee and ankle
A study of three functional components of the anterior cruciate ligament. joints, and their involvement in maintaining an upright posture.
Fibre length changes suggested that the ‘isometric point’ aimed at by some
Kawashima T, Sasaki H 2010 Reasonable classical concepts in human lower
ligament replacements lay anterior and superior to the femoral origin
limb anatomy from the viewpoint of the primitive persistent sciatic
of the intermediate fibre bundle and towards the roof of the intercondylar
artery and twisting human lower limb. Okajimas Folia Anat Jpn
notch.
87:141–9.
Amis AA, Farahmand F 1996 Biomechanics masterclass: extensor mecha- Newell RLM 1991 A complete intra-articular fat pad around the human
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Claes S, Vereecke E, Maes M et al 2013 Anatomy of the anterolateral ligament Nissman DB, Hobbs RH, Pope TL et al 2008 Imaging the knee: ligaments.
of the knee. J Anat 223:321–8. Appl Radiol 37:25–32.
Cormack GC, Lamberty BGH 1994 The Arterial Anatomy of Skin Flaps. Omololu B, Tella A, Ogunlade SO et al 2003 Normal values of knee angle,
Edinburgh: Elsevier, Churchill Livingstone. intercondylar and intermalleolar distances in Nigerian children. West
Crock HV 1967 The Blood Supply of the Lower Limb Bones in Man. London: Afr J Med 22:301–4.
Livingstone. Rajendran K 1985 Mechanism of locking at the knee joint. J Anat 143:
Falciglia F, Guzzanti V, Di Ciommo V et al 2009 Physiological knee laxity 189–94.
during pubertal growth. Bull NYU Hosp Jt Dis 67:325–9. A review of the morphological aspects of the bony knee that allow it to be
Freeman MAR, Wyke B 1967 The innervation of the knee joint: an anatomi- an efficient locking mechanism.
cal and histological study in the cat. J Anat 101:505–32. Scapinelli R 1968 Studies on the vasculature of the human knee joint. Acta
A classic paper that investigates the gross anatomy and histology of the Anat 70:305–31.
articular innervation of the knee joint. Four articular nerve endings were A primary source of detail, complementing the work of Crock on the
classified. vasculature of the bones of the lower limb.
Ghadially FN, Lalonde JM, Wedge JH 1983 Ultrastructure of normal and Seebacher JR, Inglis AE, Marshall JL et al 1982 The structure of the postero-
torn menisci of the human knee joint. J Anat 136:773–91. lateral aspect of the knee. J Bone Joint Surg 64A:536–41.
Girgis FG, Marshall JL, Al Monajem ARS 1975 The cruciate ligaments of the A work that established the current interpretation of the anatomy of the soft
knee joint. Clin Orthop 106:216–31. tissues of the knee.
A cadaveric study that described the anterior cruciate ligament as having an
Tennant TD, Birch NC, Holmes MJ et al 1998 Knee pain and the infrapatellar
anteromedial and posterolateral band. It suggested that the anteromedial
branch of the saphenous nerve. J Roy Soc Med 91:573–5.
band was responsible for the anteroposterior drawer sign with flexion.
Tubbs RS, Michelson J, Loukas M et al 2008 The transverse genicular liga-
Gronblad M, Korkala O, Leisi P et al 1985 Innervation of synovial mem- ment: anatomical study and review of the literature. Surg Radiol Anat
brane and meniscus. Acta Orthop Scand 56:484–6. 30:5–9.
Gupte CM, Bull AMJ, Thomas RD et al 2003 A review of the function A cadaveric study that identified the transverse ligament of the knee in 55%
and biomechanics of the meniscofemoral ligaments. Arthroscopy 19: of specimens, with two specimens exhibiting a duplicated ligament.
161–71.
Warren LF, Marshall JL 1979 The supporting structures and layers on the
Hamel A, Ploteau S, Lancien M et al 2012 Arterial supply to the tibial tuber- medial side of the knee: an anatomical analysis. J Bone Joint Surg 61A:
osity: involvement in patellar ligament transfer in children. Surg Radiol 56–62.
Anat 34:311–16. A cadaveric study of the medial knee that established a three-layer pattern
Jones G, Ding C, Glisson M et al 2003 Knee articular cartilage development for the regional ligaments.
in children: a longitudinal study of the effect of sex, growth, body com-
Watanabe M, Takeda S, Ikeuchi H 1979 Atlas of Arthroscopy. Berlin: Springer.
position, and physical activity. Pediatr Res 54:230–6.
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CHAPTER
83
Leg
This chapter describes the shafts of the tibia and fibula, the soft tissues soleal ridge of the tibia and to the fibula, inferomedial to the fibular
that surround them and the interosseous membrane between them. The attachment of soleus. Between these bony attachments, it is continuous
superior (proximal) and inferior (distal) tibiofibular joints are described with the fascia covering popliteus, which is, in effect, an expansion from
on pages 1385 and 1433, respectively. the tendon of semimembranosus. At intermediate levels it is thin but
distally, where it covers the tendons behind the malleoli, it is thick and
continuous with the flexor and superior fibular retinacula.
SKIN AND SOFT TISSUES
Interosseous membrane
SKIN The interosseous membrane connects the interosseous borders of the
tibia and fibula (Fig. 83.1). It is interposed between the anterior and
Vascular supply and lymphatic drainage
Posterior ligament of
The cutaneous arterial supply is derived from branches of the popliteal, fibular head
anterior tibial, posterior tibial and fibular vessels (see Fig. 78.5). Mul
tiple fasciocutaneous perforating branches from each vessel pass along Head of fibula
intermuscular septa to reach the skin; musculocutaneous perforators
traverse muscles before reaching the skin. In some areas, there is an
Ligament of Barkow
additional, direct cutaneous supply from vessels that accompany cuta
neous nerves, e.g. the descending genicular artery (saphenous artery) Opening for anterior
and superficial sural arteries. Fasciocutaneous and direct cutaneous art tibial vessels
erial branches have a longitudinal orientation in the skin, whereas the
musculocutaneous branches are more radially oriented. For further
details, consult Cormack and Lamberty (1994).
Cutaneous veins are tributaries of vessels that correspond to the
named arteries. Cutaneous lymphatic vessels running on the medial
side of the leg accompany the long saphenous vein and drain to the
superficial inguinal nodes, while those from the lateral and posterior
sides of the leg accompany the short saphenous vein and pierce the
deep fascia to drain into the popliteal nodes.
Interosseous membrane
Innervation
(syndesmosis)
The skin of the leg is supplied by branches of the saphenous, posterior
femoral cutaneous, common fibular and tibial nerves (see below and
Figs 78.11, 78.12, 78.17, 78.18).
SOFT TISSUES
Deep fascia
The deep fascia of the leg is continuous with the fascia lata and is
attached around the knee to the patellar margin, the patellar ligament,
the tuberosity and condyles of the tibia, and the head of the fibula.
Posteriorly, where it covers the popliteal fossa as the popliteal fascia,
it is strengthened by transverse fibres and is perforated by the short
saphenous vein and sural nerve. It receives lateral expansions from the
tendon of biceps femoris and multiple medial expansions from the
tendons of sartorius, gracilis, semitendinosus and semimembranosus.
The deep fascia blends with the periosteum on the subcutaneous surface
of the tibia and the subcutaneous surfaces of the fibular head and lateral Opening for perforating
branch of fibular artery
malleolus, and is continuous below with the extensor and flexor reti
nacula. It is thick and dense in the proximal and anterior part of the
leg, where fibres of tibialis anterior and extensor digitorum longus are
attached to its deep surface, and is thinner posteriorly, where it covers
gastrocnemius and soleus. On the lateral side, it is continuous with the
anterior and posterior intermuscular septa of the leg, which are attached
to the anterior and posterior borders of the fibula, respectively. Groove for tendon
of tibialis posterior
Transverse intermuscular septum
The transverse intermuscular septum of the leg is a fibrous stratum
between the superficial and deep muscles of the calf. It extends trans Inferior transverse ligament
versely from the medial margin of the tibia to the posterior border of Fig. 83.1 The posterior aspect of the interosseous membrane. Note the
1400 the fibula. Proximally, where it is thick and dense, it is attached to the contrasting direction of the fibre bundles around the vascular openings. | 1,919 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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A Tibialis anterior B
Tibialis posterior
Tibia
Extensor digitorum longus
Popliteus, lowest part
Anterior tibial artery
Fibularis longus
Flexor digitorum longus
Posterior tibial artery Deep fibular nerve
and tibial nerve Superficial fibular nerve
Long saphenous vein
Fibula
Fibular artery
Flexor hallucis longus
Gastrocnemius,
medial head Gastrocnemius,
lateral head
Cutaneous vein
Soleus
Sural communicating branch
Plantaris
Sural nerve Short saphenous vein
Fig. 83.2 A, A transverse (axial) section through the left leg, approximately 10 cm distal to the knee joint. B, Colour-coded axial magnetic resonance
imaging (MRI) of the leg. Observe the anterior (blue), lateral (red) and posterior (deep part yellow and superficial part green) compartments of the leg.
(C, continued online)
posterior groups of crural muscles; some members of each group are with an additional contribution from the fibular artery to extensor hal
attached to the corresponding surface of the interosseous membrane. lucis longus. The muscles of the posterior compartment are supplied by
The anterior tibial artery passes forwards through a large oval opening the popliteal, posterior tibial and fibular arteries. The muscles of the
near the proximal end of the membrane, and the perforating branch of lateral compartment are supplied by the anterior tibial and fibular arter
the fibular artery pierces it distally. An associated ligament (ligament of ies, and to a lesser extent proximally, by a branch from the popliteal
Barkow), in the same plane as the interosseous membrane, may be artery.
found uniting the proximal tibiofibular joint; when present, it forms
the upper half of this oval opening (see Fig. 83.1) (Tubbs et al 2009). Trauma and soft tissues of the leg
Its fibres are predominantly oblique and most descend laterally; those The relative paucity of soft tissue in the shin region and the subcutan
that descend medially include a bundle at the proximal border of the eous position of the medial surface of the tibia means that even trivial
proximal opening. The thickness of the interosseous membrane differs soft tissue injury may lead to serious problems such as ulceration and
between its thin centre and thick tibial and fibular borders. The mem osteomyelitis. In the elderly, these soft tissues are often especially thin
brane is continuous distally with the interosseous ligament of the distal and unhealthy, reflecting the effects of ageing and venous stasis (see
tibiofibular joint. below). Tibial fractures are common in the young and, partly as a result
of poor soft tissue coverage, they are often open injuries. Diminished
Retinacula
blood supply to the bone, caused by traumatic stripping of attached
The retinacula at the ankle joint are described on page 1418.
soft tissues, and the risk of contamination add greatly to the risk of
Osteofascial compartments nonunion and infection of the fracture. Healing of fractures at the
junction of the middle and lower thirds of the tibia is compromised by
The compartments of the leg are particularly well defined and are the
the relatively poor blood supply to this region. Injury to the leg may
most common sites at which osteofascial compartment syndromes
result in elevated pressures of one or more compartments (socalled
occur. The three main compartments are anterior (extensor), lateral
compartment syndrome); this clinical scenario is manifested by the ‘six
(fibular) and posterior (flexor). The posterior compartment is divided
Ps’: pain, paraesthesias, pallor, paralysis, pulselessness and poikilother
into deep and superficial parts by the transverse intermuscular septum
mia (differing temperatures in the affected and unaffected limbs).
(Fig. 83.2). These compartments are enclosed by the unyielding deep
fascia and separated from each other by the bones of the leg and inter
osseous membrane, and by the anterior and posterior intermuscular
BONES
septa that pass from the deep fascia to the fibula. The anterior compart
ment, the least expansile of the three, is bounded by the deep fascia,
the interosseous surfaces of the tibia and fibula, the interosseous mem TIBIA
brane and the anterior intermuscular septum. The lateral compartment
lies between the anterior and posterior intermuscular septa, and is The tibia lies medial to the fibula and is exceeded in length only by the
bordered laterally by the deep fascia and medially by the lateral surface femur (Figs 83.3–83.4). The tibial shaft is triangular in section and has
of the fibula. The posterior compartment is bounded by the deep fascia, expanded ends; a strong medial malleolus projects distally from the
the posterior intermuscular septum, the fibula and tibia, and the inter smaller distal end. The anterior border of the shaft is sharp and curves
osseous membrane. Its relatively expansile superficial component is medially towards the medial malleolus. Together with the medial and
separated from the compacted deep component by the transverse inter lateral borders, it defines the three surfaces of the bone. The exact shape
muscular septum, reinforced by the deep aponeurosis of soleus. Knowl and orientation of these surfaces show individual and racial variations.
edge of the compartmental anatomy of the leg is important in planning In children, the mean tibial length is greater in males than in females
the treatment of compartment syndromes and for soft tissue tumour (Oeffinger et al 2010).
resections of the leg.
The nerve supply of the muscles in the compartments follows the Proximal end
‘one compartment – one nerve’ principle: the deep fibular nerve sup The expanded proximal end bears the weight transmitted through the
plies the anterior compartment, the superficial fibular nerve supplies femur. It consists of medial and lateral condyles, an intercondylar area
the lateral compartment, and the tibial nerve supplies the posterior and the tibial tuberosity.
compartment. Magnetic resonance imaging (MRI) is the best imaging
modality for evaluating the soft tissues of the leg. Most of the muscle Condyles The tibial condyles overhang the proximal part of the pos
in the anterior compartment is supplied by the anterior tibial artery, terior surface of the shaft. Both condyles have articular facets on their | 1,920 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Leg
C
Fig. 83.2 C, An axial T2-weighted MRI of the leg in a patient with anterior
compartment denervation (arrow).
1401.e1 | 1,921 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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NOITCES
A B Fig. 83.3 A, The left tibia and fibula, anterior
aspect. Key: 1, medial condyle; 2, tibial tuberosity;
10
1 7 3, anterior border of tibia; 4, interosseous border
1 11 of tibia; 5, medial surface; 6, medial malleolus; 7,
8 2 Gerdy’s tubercle; 8, lateral condyle; 9, head of
12
2 3 13 fibula; 10, interosseous border of fibula; 11,
9 4 anterior border of fibula; 12, medial crest; 13,
14 anterior surface; 14, subcutaneous area; 15, lateral
15 malleolus. B, The muscle attachments. Key: 1,
semimembranosus; 2, medial patellar retinaculum;
5 3, epiphysial line (growth plate); 4, tibial collateral
6 16 ligament; 5, gracilis; 6, sartorius; 7,
7 17 semitendinosus; 8, tibialis anterior; 9, capsular
attachment; 10, iliotibial tract; 11, capsular
18 attachment; 12, fibular collateral ligament; 13,
8 biceps femoris; 14, patellar ligament; 15,
epiphysial line (growth plate); 16, fibularis longus;
17, extensor digitorum longus; 18, tibialis
3 posterior; 19, fibularis brevis; 20, extensor hallucis
longus; 21, extensor digitorum longus; 22, fibularis
19
tertius; 23, epiphysial line (growth plate); 24,
epiphysial line (growth plate).
10
4
20
11
21
12
13
5
22
14 23
9
24
6
15
superior surfaces, separated by an irregular, nonarticular intercondylar edge is a sharp ridge between the lateral condyle and lateral surface of
area. The condyles are visible and palpable at the sides of the patellar the shaft. The condyles, their articular surfaces and the intercondylar
ligament, the lateral being more prominent. In the passively flexed area are described on pages 1386–1387.
knee, the anterior margins of the condyles are palpable in depressions
that flank the patellar ligament. Tibial tuberosity The tibial tuberosity is the truncated apex of a
The fibular articular facet on the posteroinferior aspect of the lateral triangular area where the anterior condylar surfaces merge. It projects
condyle faces distally and posterolaterally. The angle of inclination of only a little, and is divided into distal rough and proximal smooth
the superior tibiofibular joint varies between individuals, and may be regions. The distal region is palpable and is separated from skin by the
horizontal or oblique. Superomedial to it, the condyle is grooved on subcutaneous infrapatellar bursa. A line across the tibial tuberosity
its posterolateral aspect by the tendon of popliteus; a synovial recess marks the distal limit of the proximal tibial growth plate (see Fig. 83.3).
intervenes between the tendon and bone. The anterolateral aspect of The patellar ligament is attached to the smooth bone proximal to this,
the condyle is separated from the lateral surface of the shaft by a sharp its superficial fibres reaching a rough area distal to the line. The deep
margin for the attachment of deep fascia. The distal attachment of the infrapatellar bursa and fibroadipose tissue intervene between the bone
iliotibial tract makes a flat and usually definite marking (Gerdy’s tuber and tendon proximal to its site of attachment. The latter may be marked
cle) on its anterior aspect. This tubercle, which is triangular and facet distally by a somewhat oblique ridge, on to which the lateral fibres of
like, is usually palpable through the skin. the patellar ligament are inserted more distally than the medial fibres.
The anterior condylar surfaces are continuous with a large triangular This knowledge is necessary for avoiding damage to this structure when
area whose apex is distal and formed by the tibial tuberosity. The lateral performing an osteotomy just above the tibial tuberosity in a lateral to | 1,922 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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A 10 B Fig. 83.4 A, The left tibia and fibula, posterior
6
1 aspect. Key: 1, groove for tendon of popliteus;
1 2, apex of head of fibula; 3, head of fibula; 4, neck
2 11 of fibula; 5, medial crest; 6, interosseous border of
7 tibia; 7, posterior border; 8, groove for fibular
3 tendons; 9, lateral malleolus; 10, intercondylar
8 eminence; 11, groove for semimembranosus
4
attachment; 12, soleal line; 13, nutrient foramen;
14, vertical line; 15, medial border of tibia; 16,
9
medial malleolus; 17, groove for tibialis posterior
2 tendon. B, The muscle attachments. Key: 1, gap
in capsule for popliteus tendon; 2, soleus; 3, flexor
10
12 hallucis longus; 4, fibularis brevis; 5, epiphysial
line (growth plate); 6, capsular attachment; 7,
semimembranosus; 8, epiphysial lines (growth
plates); 9, popliteus; 10, soleus; 11, tibialis
posterior; 12, flexor digitorum longus; 13,
13 epiphysial line (growth plate); 14, capsular
attachment.
5 3
11
14
12
15
6
7
4
13
16 5
8
17 14
9
medial direction. In habitual squatters, a vertical groove on the anterior The anteromedial surface, between the anterior and medial borders,
surface of the lateral condyle is occupied by the lateral edge of the is broad, smooth and almost entirely subcutaneous. The lateral surface,
patellar ligament in full flexion of the knee. between the anterior and interosseous borders, is also broad and
smooth. It faces laterally in its proximal threequarters and is trans
Shaft versely concave. Its distal quarter bends to face anterolaterally, on
The shaft is triangular in section and has (antero)medial, lateral and account of the medial deviation of the anterior and distal interosseous
posterior surfaces separated by anterior, lateral (interosseous) and borders. This part of the surface is somewhat convex. The posterior
medial borders. It is narrowest at the junction of the middle and distal surface, between the interosseous and medial borders, is widest above,
thirds, and expands gradually towards both ends. The anterior border where it is crossed distally and medially by an oblique, rough soleal
descends from the tuberosity to the anterior margin of the medial line. A faint vertical line descends from the centre of the soleal line for
malleolus and is subcutaneous throughout. Except in its distal quarter, a short distance before becoming indistinct. A large vascular groove
where it is indistinct, it is a sharp crest. It is slightly sinuous, and turns adjoins the end of the line and descends distally into a nutrient foramen.
medially in the distal quarter. The interosseous border begins distal and Deep fascia and, proximal to the medial malleolus, the medial end of
anterior to the fibular articular facet and descends to the anterior border the superior extensor retinaculum are attached to the anterior border.
of the fibular notch; it is indistinct proximally. The interosseous mem Posterior fibres of the tibial collateral ligament and slips of semimem
brane is attached to most of its length, connecting the tibia to the fibula. branosus and the popliteal fascia are attached to the medial border
The medial border descends from the anterior end of the groove on the proximal to the soleal line, and some fibres of soleus and the fascia
medial condyle to the posterior margin of the medial malleolus. Its covering the deep calf muscles are attached distal to the line. The distal
proximal and distal quarters are ill defined but its central region is sharp medial border runs into the medial lip of a groove for the tendon of
and distinct. tibialis posterior. The interosseous membrane is attached to the lateral | 1,923 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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border, except at either end of this border. It is indistinct proximally Muscle attachments
where a large gap in the membrane transmits the anterior tibial vessels. The patellar ligament is attached to the proximal half of the tibial
Distally, the border is continuous with the anterior margin of the fibular tuberosity. Semimembranosus is attached to the distal edge of the
notch, to which the anterior tibiofibular ligament is attached. groove on the posterior surface of the medial condyle; a tubercle at the
The anterior part of the tibial collateral ligament is attached to an lateral end of the groove is the main attachment of the tendon of this
area approximately 5 cm long and 1 cm wide near the medial border muscle. Slips from the tendon of biceps femoris are attached to the
of the proximal medial surface. The remaining medial surface is subcu lateral tibial condyle anteroproximal to the fibular articular facet (see
taneous and crossed obliquely by the long saphenous vein. Tibialis Fig. 83.3B). Proximal fibres of extensor digitorum longus and (occa
anterior is attached to the proximal twothirds of the lateral surface. The sionally) fibularis longus are attached distal to this area. Slips of semi
distal third, devoid of attachments, is crossed in mediolateral order by membranosus are attached to the medial border of the shaft posteriorly,
the tendons of tibialis anterior (lying just lateral to the anterior border), proximal to the soleal line. Some fibres of soleus attach to the postero
extensor hallucis longus, the anterior tibial vessels and deep fibular medial surface distal to the line. Semimembranosus is attached to the
nerve, extensor digitorum longus and fibularis tertius. medial surface proximally, near the medial border, behind the attach
On the posterior surface, popliteus is attached to a triangular area ment of the anterior part of the tibial collateral ligament. Anterior to
proximal to the soleal line, except near the fibular articular facet. The this area (in anteroposterior sequence) are the linear attachments of
popliteal aponeurosis, soleus and its fascia, and the transverse inter the tendons of sartorius, gracilis and semitendinosus; these rarely mark
muscular septum are all attached to the soleal line; the proximal end the bone. Tibialis anterior is attached to the proximal twothirds of the
of the line does not reach the interosseous border, and is marked by a lateral (extensor) surface. Popliteus is attached to the posterior surface
tubercle for the medial end of the tendinous arch of soleus. Lateral to in a triangular area proximal to the soleal line, except near the fibular
the tubercle, the posterior tibial vessels and tibial nerve descend on articular facet (see Fig. 83.4B). Soleus and its associated fascia are
tibialis posterior. Distal to the soleal line, a vertical line separates the attached to the soleal line itself. Flexor digitorum longus and tibialis
attachments of flexor digitorum longus and tibialis posterior. Nothing posterior are attached to the posterior surface distal to the soleal line,
is attached to the distal quarter of this surface, but the area is crossed medial and lateral, respectively, to the vertical line (see above).
medially by the tendon of tibialis posterior travelling to a groove on
the posterior aspect of the medial malleolus. Flexor digitorum longus Vascular supply
crosses obliquely behind tibialis posterior; the posterior tibial vessels The proximal end of the tibia is supplied by metaphysial arteries from
and nerve and flexor hallucis longus contact only the lateral part of the the genicular anastomosis. The nutrient foramen usually lies near the
distal posterior surface. soleal line and transmits a branch of the posterior tibial artery; the
nutrient vessel may also arise at the level of the popliteal bifurcation or
Distal end
as a branch from the anterior tibial artery. On entering the bone, the
The slightly expanded distal end of the tibia has anterior, medial, pos nutrient artery divides into ascending and descending branches. The
terior, lateral and distal surfaces. It projects inferomedially as the medial periosteal supply to the shaft arises from the anterior tibial artery and
malleolus. The distal end of the tibia, when compared to the proximal from muscular branches. The distal metaphysis is supplied by branches
end, is laterally rotated (tibial torsion). The torsion begins to develop from the arterial anastomosis around the ankle.
in utero and progresses throughout childhood, mainly during the first
four years of life (Kristiansen et al 2001), until skeletal maturity is Innervation
attained. Some of the femoral neck anteversion seen in the newborn The proximal and distal ends of the tibia are innervated by branches
may persist in adult females: this causes the femoral shaft and knee to from the nerves that supply the knee joint and ankle joint, respectively.
be medially rotated, which may lead the tibia to develop a compens The periosteum of the shaft is supplied by branches from the nerves
atory external torsion to counteract the tendency of the feet to turn that innervate the muscles attached to the tibia.
inwards. Tibial torsion is approximately 30° in Caucasian and Asian
populations, but is significantly greater in Africans (Eckhoff et al 1994). Ossification
The smooth anterior surface projects beyond the distal surface, from The tibia ossifies from three centres: one in the shaft and one in each
which it is separated by a narrow groove. The capsule of the ankle joint epiphysis. Ossification (see Figs 83.3–83.4; Fig. 83.5) begins in mid
is attached to an anterior groove near the articular surface. The medial shaft at about the seventh intrauterine week. The proximal epiphysial
surface is smooth and continuous above and below with the medial centre is usually present at birth: at approximately 10 years, a thin
surfaces of the shaft and medial malleolus, respectively; it is subcutan anterior process from the centre descends to form the smooth part of
eous and visible. The posterior surface is smooth except where it is the tibial tuberosity. A separate centre for the tuberosity may appear at
crossed near its medial end by a nearly vertical but slightly oblique about the twelfth year and soon fuses with the epiphysis. Distal strata
groove, which is usually conspicuous and extends to the posterior of the epiphysial plate are composed of dense collagenous tissue in
surface of the malleolus. The groove is adapted to the tendon of tibialis which the fibres are aligned with the patellar ligament. Exaggerated
posterior, which usually separates the tendon of flexor digitorum longus traction stresses may account for Osgood–Schlatter disease, in which
from the bone. More laterally, the posterior tibial vessels, tibial nerve
and flexor hallucis longus contact this surface. The lateral surface is the
Joins shaft sixteenth
triangular fibular notch; its anterior and posterior edges project and
to eighteenth year
converge proximally to the interosseous border. The floor of the notch
is roughened proximally by a substantial interosseous ligament but is
smooth distally and is sometimes covered by articular cartilage. The
anterior and posterior tibiofibular ligaments are attached to the corre
sponding edges of the notch. The distal surface articulates with the talus
and is wider in front, concave sagittally and slightly convex transversely,
i.e. saddleshaped. Medially, it continues into the malleolar articular
surface, which may extend into the groove that separates it from the
anterior surface of the shaft. Such extensions, medial or lateral or both,
are squatting facets, and they articulate with reciprocal talar facets in At birth End of Twelfth Sixteenth to
extreme dorsiflexion. These features have been used in the field of first year year eighteenth year
forensic medicine to identify the race of skeletal material.
Medial malleolus The short, thick medial malleolus has a smooth
lateral surface with a crescentic facet that articulates with the medial
surface of the talus. Its anterior aspect is rough and its posterior aspect
features the continuation of the groove from the posterior surface of
the tibial shaft for the tendon of tibialis posterior. The distal border is
pointed anteriorly, posteriorly depressed, and gives attachment to the
deltoid ligament. The tip of the medial malleolus does not project as
far distally as the tip of the lateral malleolus, the latter also being the
more posteriorly located of the two malleoli. The capsule of the ankle Joins shaft
Unossified (cartilaginous) regions sixteenth to eighteenth year
joint is attached to the anterior surface of the medial malleolus, and
the flexor retinaculum is attached to its prominent posterior border. Fig. 83.5 Stages in the ossification of the tibia (not to scale). | 1,924 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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fragmentation of the epiphysis of the tibial tuberosity occurs during interosseous ligament. The interosseous membrane attached to this
adolescence and produces a painful swelling around it. Healing occurs border does not reach the fibular head, which leaves a gap through
once the growth plate fuses, leaving a bony protrusion. Prolonged which the anterior tibial vessels pass. The posterior border is proximally
periods of traction with the knee extended, both in children and adol indistinct, and the posterior intermuscular septum is attached to all but
escents, can lead to growth arrest of the anterior part of the proximal its distal end. The medial crest is related to the fibular artery. A layer of
epiphysis, which results in bowing of the proximal tibia as the posterior deep fascia separating the tendon of tibialis posterior from flexor hal
tibia continues to grow. The proximal epiphysis fuses in the sixteenth lucis longus and flexor digitorum longus is attached to the medial crest.
year in females and the eighteenth in males. The distal epiphysial centre
appears early in the first year and joins the shaft at about the fifteenth Lateral malleolus
year in females and the seventeenth in males. The medial malleolus is The distal end of the fibula forms the lateral malleolus, which projects
an extension from the distal epiphysis and starts to ossify in the seventh distally and posteriorly (see Figs 83.3–83.4). Its lateral aspect is subcu
year; it may have its own separate ossification centre. An accessory taneous while its posterior aspect has a broad groove with a prominent
ossification centre sometimes appears at the tip of the medial malleo lateral border. Its anterior aspect is rough, round and continuous with
lus, more often in females than in males. It fuses during the eighth year the tibial inferior border. The medial surface has a triangular articular
in females and the ninth year in males; it should not be confused with facet, vertically convex, its apex distal, which articulates with the lateral
an os subtibiale, which is a rare accessory bone found on the posterior talar surface. Behind this facet is a rough malleolar fossa pitted by vas
aspect of the medial malleolus. The average growth rate of the distal cular foramina. The posterior tibiofibular ligament and, more distally,
tibia decreases from a plateau of about 11 years of age in boys and 10 the posterior talofibular ligament, are attached in the fossa. The ant
years of age in girls (Kärrholm et al 1984). erior talofibular ligament is attached to the anterior surface of the
lateral malleolus; the calcaneofibular ligament is attached to the notch
anterior to its apex. The tendons of fibularis brevis and longus groove
FIBULA its posterior aspect; the latter is superficial and covered by the superior
fibular retinaculum.
The fibula (see Figs 83.3–83.4) is much more slender than the tibia and
Muscle attachments
is not directly involved in transmission of weight. It has a proximal
head, a narrow neck, a long shaft and a distal lateral malleolus. The The main attachments of biceps femoris embrace the fibular collateral
shaft varies in form, being variably moulded by attached muscles; these ligament in front of the apex of the fibular head. Extensor digitorum
variations may be confusing. longus is attached to the head anteriorly, fibularis longus anterolat
erally, and soleus posteriorly. Extensor digitorum longus, extensor hal
Head lucis longus and fibularis tertius are attached to the anteromedial
The head of the fibula is irregular in shape and projects anteriorly, (extensor) surface. Fibularis longus is attached to the whole width of
posteriorly and laterally. A round facet on its proximomedial aspect the lateral (fibular) surface in its proximal third, but in its middle third
articulates with a corresponding facet on the inferolateral surface of the only to its posterior part, behind fibularis brevis. The latter continues
lateral tibial condyle. It faces proximally and anteromedially, and has its attachment almost to the distal end of the shaft.
an inclination that may vary among individuals from almost horizontal Muscle attachments to the posterior surface, which is divided longi
to an angle of up to 45°. A blunt apex projects proximally from the tudinally by the medial crest, are complex. Between the crest and inter
posterolateral aspect of the head and is often palpable approximately osseous border, the posterior surface is concave. Tibialis posterior is
2 cm distal to the knee joint. The fibular collateral ligament is attached attached throughout most (the proximal threequarters) of this area; an
in front of the apex, embraced by the main attachment of biceps intramuscular tendon may ridge the bone obliquely. Soleus is attached
femoris. The tibiofibular joint capsule is attached to the margins of the between the crest and the posterior border on the proximal quarter of
articular facet. The common fibular nerve crosses posterolateral to the the posterior surface; its tendinous arch is attached to the surface proxi
neck and can be rolled against the underlying bone at this location. mally (see Fig. 83.4B). Flexor hallucis longus is attached distal to soleus
on the posterior surface and almost reaches the distal end of the shaft.
Shaft
The shaft has three borders and surfaces, each associated with a particu Vascular supply
lar group of muscles. The anterior border ascends proximally from the A little proximal to the midpoint of the posterior surface (14–19 cm
apex of an elongated triangular area that is continuous with the lateral from the apex), a distally directed nutrient foramen on the fibular shaft
malleolar surface, to the anterior aspect of the fibular head. The poste receives a branch of the fibular artery. An appreciation of the detailed
rior border, continuous with the medial margin of the posterior groove anatomy of the fibular artery in relation to the fibula is fundamental to
on the lateral malleolus, is usually distinct distally but often rounded the raising of osteofasciocutaneous free flaps. Free vascularized diaphys
in its proximal half. The interosseous border is medial to the anterior ial grafts may also be taken on a fibular arterial pedicle. The proximal
border and somewhat posterior. Over the proximal twothirds of the and distal ends receive metaphysial vessels from the arterial anastomo
fibular shaft the two borders approach each other, with the surface ses at the knee and ankle, respectively (Taylor and Razaboni 1994).
between the two being narrowed to 1 mm or less.
The lateral surface, between the anterior and posterior borders and Innervation
associated with the fibular muscles, faces laterally in its proximal three The proximal and distal ends of the bone are supplied by branches of
quarters. The distal quarter spirals posterolaterally to become continu nerves that innervate the knee and superior tibiofibular joint, and the
ous with the posterior groove of the lateral malleolus. The anteromedial ankle and inferior tibiofibular joints, respectively. The periosteum of
(sometimes simply termed anterior, or medial) surface, between the the shaft is supplied by branches from the nerves that innervate the
anterior and interosseous borders, usually faces anteromedially but muscles attached to the fibula.
often directly anteriorly. It is associated with the extensor muscles.
Though wide distally, it narrows in its proximal half and may become Ossification
a mere ridge. The posterior surface, between the interosseous and pos The fibula ossifies from three centres: one each for the shaft and the
terior borders, is the largest and is associated with the flexor muscles. extremities. The process begins in the shaft at about the eighth week in
Its proximal twothirds are divided by a longitudinal medial crest, sepa utero; in the distal end in the first year; and in the proximal end at about
rated from the interosseous border by a grooved surface that is directed the third year in females and the fourth year in males. The distal epi
medially. The remaining surface faces posteriorly in its proximal half; physis unites with the shaft at about the fifteenth year in females and
its distal half curves on to the medial aspect. Distally, this area occupies the seventeenth year in males, whereas the proximal epiphysis does not
the fibular notch of the tibia, which is roughened by the attachment of unite until about the seventeenth year in females and the nineteenth
the principal interosseous tibiofibular ligament. The triangular area year in males. A longitudinal radiographic study of children has shown
proximal to the lateral surface of the lateral malleolus is subcutaneous; that the proximal growth plate of the fibula contributes more to growth
muscles cover the rest of the shaft. than the proximal growth plate of the tibia, their growth contributions
The anterior border is divided distally into two ridges that enclose a being 61% and 57%, respectively (Pritchett and Bortel 1997).
triangular subcutaneous surface. The anterior intermuscular septum is
attached to its proximal threequarters. The lateral end of the superior
MUSCLES
extensor retinaculum is attached distally on the anterior border of the
triangular area and the lateral end of the superior fibular retinaculum
is attached distally on the posterior margin of the triangular area. The The muscles of the leg consist of an anterior group of extensor muscles,
interosseous border ends at the proximal limit of the rough area for the which produce dorsiflexion (extension) of the ankle; a posterior group | 1,925 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Leg
An os subfibulare is an occasional and separate entity and lies pos
terior to the tip of the fibula, whereas the distal fibular apophysis lies
anteriorly. An os retinaculi is rarely encountered; if present, it overlies
the bursa of the distal fibula within the fibular retinaculum. Fibular
dimelia is characterized by duplication of the fibula, tibial aplasia and
partial duplication of the foot with mirror polydactyly, and may be
associated with ulnar dimelia and calcaneal duplication. It has been
postulated that a reestablishment of limb polarity during embryogen
esis may account for this condition (Bayram et al 1996, Ganey et al
2000).
1405.e1 | 1,926 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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NOITCES
A B
Patella Biceps femoris
Iliotibial tract Vastus lateralis
Patellar ligament
Iliotibial tract
Tibial tuberosity Patella
Patellar ligament Head of fibula
Gastrocnemius
Fibularis longus Gastrocnemius
Fibularis longus
Tibialis anterior
Soleus
Extensor digitorum longus Tibialis anterior
Soleus
Tibia Fibularis brevis
Extensor digitorum longus
Fibularis brevis
Tibialis anterior
Extensor hallucis longus
Calcaneal tendon
Extensor hallucis longus Inferior extensor retinaculum
Lateral malleolus
Extensor
hallucis brevis
Superior fibular
Medial malleolus retinaculum
Lateral malleolus
Inferior extensor Fibularis
retinaculum longus
Extensor digitorum longus
Extensor Fibularis
hallucis longus brevis
Fibularis tertius
Extensor digitorum longus Fibularis tertius Extensor digitorum brevis
Extensor
hallucis brevis Extensor digitorum brevis
Fig. 83.6 Muscles of the left leg and foot. The fasciae have been
removed. A, Anterior view. B, Lateral view. (With permission from
Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed,
Elsevier, Urban & Fischer. Copyright 2013.)
of flexor muscles, which produce plantar flexion (flexion); and a lateral Attachments to the talus, first metatarsal head, base of the proximal
group of muscles, which evert the ankle and which are derived, embryo phalanx of the hallux, and extensor retinaculum have been recorded.
logically, from the anterior muscle group. The greater bulk of the
muscles in the calf is commensurate with the powerful propulsive role Relations Tibialis anterior overlaps the anterior tibial vessels and
of the plantar flexors in walking and running. deep fibular nerve in the upper part of the leg. It lies on the tibia and
interosseous membrane. Extensor digitorum longus and extensor hal
lucis longus lie laterally.
ANTERIOR OR EXTENSOR COMPARTMENT
Vascular supply The main body of tibialis anterior is supplied by a
The anterior compartment contains muscles that dorsiflex the ankle series of medial and anterior branches of the anterior tibial artery; the
when acting from above (see Fig. 83.2A, B; Fig. 83.6). When acting from branches may occur in two columns. There is a proximal accessory
below, they pull the body forwards on the fixed foot during walking. supply from the anterior tibial recurrent artery. The tendon is supplied
Two of the muscles, extensor digitorum longus and extensor hallucis by the anterior medial malleolar artery and network, dorsalis pedis
longus, also extend the toes, and two muscles, tibialis anterior and artery, medial tarsal arteries, and by the medial malleolar and calcaneal
fibularis tertius, have the additional actions of inversion and eversion, branches of the posterior tibial artery.
respectively.
Innervation Tibialis anterior is innervated by the deep fibular nerve,
Tibialis anterior
L4 and L5.
Attachments Tibialis anterior is a superficial muscle and is therefore
readily palpable lateral to the tibia. It arises from the lateral condyle Actions Tibialis anterior dorsiflexes and inverts the foot. It is most
and proximal onehalf to twothirds of the lateral surface of the tibial active when both movements are combined, as in walking. Its tendon
shaft; the adjoining anterior surface of the interosseous membrane; the can be seen through the skin lateral to the anterior border of the tibia
deep surface of the deep fascia; and the intermuscular septum between and can be traced downwards and medially across the front of the ankle
itself and extensor digitorum longus. The muscle descends vertically to the medial side of the foot. Tibialis anterior elevates the first meta
and ends in a tendon on its anterior surface in the lower third of the tarsal base and medial cuneiform, and rotates their dorsal aspects
leg. The tendon passes through the medial compartments of the supe laterally.
rior and inferior retinacula, inclines medially, and is inserted on to the The muscle is usually quiescent while standing, since the weight of
medial and inferior surfaces of the medial cuneiform and the adjoining the body acts through vertical lines that pass anterior to the ankle joints.
part of the base of the first metatarsal. Acting from below, it helps to counteract any tendency to overbalance | 1,927 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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backwards by flexing the leg forwards at the ankle. It has a role in sup
porting the medial part of the longitudinal arch of the foot; although
electromyographically detectable activity is minimal during standing, it
is manifest during any movement that increases the arch, such as toeoff Superior medial
in walking and running. genicular artery Superior lateral
genicular artery
Testing Tibialis anterior can be seen to act when the foot is dorsiflexed
against resistance. Dorsiflexion is best tested by asking the subject to
walk on their heels.
Extensor hallucis longus
Attachments Extensor hallucis longus lies between, and is partly
overlapped by, tibialis anterior and extensor digitorum longus (see Figs
Tibialis
83.6A, B). It arises from the middle half of the medial surface of the
anterior (cut)
fibula, medial to extensor digitorum longus, and from the adjacent Anterior tibial
recurrent artery
anterior surface of the interosseous membrane. Its fibres run distally
and end in a tendon that forms on the anterior border of the muscle.
The tendon passes deep to the superior extensor retinaculum and
through the inferior extensor retinaculum, crosses anterior to the ante
rior tibial vessels to lie on their medial side near the ankle, and is
inserted on to the dorsal aspect of the base of the distal phalanx of the
hallux. At the metatarsophalangeal joint, a thin prolongation from each
side of the tendon covers the dorsal surface of the joint. An expansion
from the medial side of the tendon to the base of the proximal phalanx
Anterior tibial artery
is usually present.
Extensor hallucis longus is sometimes united with extensor digit
orum longus and may send a slip to the second toe.
Relations The anterior tibial vessels and deep fibular nerve lie between
extensor hallucis longus and tibialis anterior. Extensor hallucis longus
lies lateral to the artery proximally, crosses it in the lower third of the
leg, and is medial to it on the foot.
Vascular supply Extensor hallucis longus is supplied by the anterior
tibial artery via obliquely running branches, with a variable contribu Extensor digitorum longus
tion from the perforating branch of the fibular artery (Fig. 83.7). More
distally, the tendon is supplied via the anterior medial malleolar artery
Tibialis
and network, the dorsalis pedis artery, and the plantar metatarsal artery
of the first digit via perforating branches. anterior (cut) Extensor hallucis longus
Innervation Extensor hallucis longus is innervated by the deep fibular
nerve, L5.
Anterior lateral malleolar artery
Actions Extensor hallucis longus extends the hallux and dorsiflexes Perforating branch
the foot. When the hallux is actively extended, relatively little external of fibular artery
force is required to overcome the extension of the distal phalanx, Anterior medial
malleolar artery
whereas considerable force is needed to overcome the extension of the
proximal phalanx.
Lateral tarsal artery
Testing When the hallux is extended against resistance, the tendon of
extensor hallucis longus can be seen and felt on the lateral side of the Dorsalis pedis artery
tendon of tibialis anterior.
Extensor hallucis brevis
Extensor digitorum longus
Attachments Extensor digitorum longus arises from the inferior Arcuate artery
surface of the lateral condyle of the tibia, the proximal threequarters
First dorsal
of the medial surface of the fibula, the adjacent anterior surface of the
metatarsal artery
interosseous membrane, the deep surface of the deep fascia, the anterior
intermuscular septum and the fascial septum between itself and tibialis
anterior. These origins form the walls of an osseoaponeurotic tunnel.
Extensor digitorum longus becomes tendinous at about the same level
as tibialis anterior, and the tendon passes deep to the superior extensor
retinaculum and within a loop of the inferior extensor retinaculum with
fibularis tertius (see Figs 83.6, 84.1). It divides into four slips, which Fig. 83.7 The left anterior tibial and dorsalis pedis arteries. To expose the
run forwards on the dorsum of the foot and are attached in the same anterior tibial artery, a large part of tibialis anterior has been excised.
way as the tendons of extensor digitorum in the hand. At the metatarso
phalangeal joints, the tendons to the second, third and fourth toes are
each joined on the lateral side by a tendon of extensor digitorum brevis. Tibialis anterior and extensor hallucis longus lie medially in the leg,
The socalled dorsal digital expansions thus formed on the dorsal and the fibular muscles lie laterally. In the upper part of the leg, the
aspects of the proximal phalanges, as in the fingers, receive contribu anterior tibial vessels and deep fibular nerve lie between extensor digi
tions from the appropriate lumbrical and interosseous muscles. The torum longus and tibialis anterior; the nerve runs obliquely and medi
expansion narrows as it approaches a proximal interphalangeal joint, ally beneath its upper part.
and divides into three slips. These are a central (axial) slip, attached to
the base of the middle phalanx, and two collateral (coaxial) slips, which Vascular supply The main blood supply to extensor digitorum
reunite on the dorsum of the middle phalanx and are attached to the longus is derived from anteriorly and laterally placed branches of the
base of the distal phalanx. anterior tibial artery, supplemented distally from the perforating branch
The tendons to the second and fifth toes are sometimes duplicated, of the fibular artery. Proximally, there may also be a supply from the
and accessory slips may be attached to metatarsals or to the hallux. inferior lateral genicular, popliteal or anterior tibial recurrent arteries.
At the ankle and in the foot, the tendons are supplied by the anterior
Relations Extensor digitorum longus lies on the lateral tibial condyle, lateral malleolar artery and malleolar network, and by lateral tarsal,
fibula, lower end of the tibia, ankle joint and extensor digitorum brevis. metatarsal, plantar and digital arteries. | 1,928 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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NOITCES
Innervation Extensor digitorum longus is innervated by the deep and on the cuboid bone. At both sites it is thickened, and at the second
fibular nerve, L5, S1. site a sesamoid fibrocartilage (sometimes a bone, the os peroneum) is
usually present. A second synovial sheath invests the tendon as it crosses
Actions Extensor digitorum longus extends the lateral four toes. the sole of the foot.
Acting synergistically with tibialis anterior, extensor hallucis longus and
fibularis tertius, it is a dorsiflexor of the ankle. Acting with extensor Relations Proximally, fibularis longus lies posterior to extensor digi
hallucis longus, it helps tighten the plantar aponeurosis. torum longus and anterior to soleus and flexor hallucis longus. Distally,
in the leg, it lies posterior to fibularis brevis. Between its attachments
Testing The tendons of extensor digitorum longus can be seen when to the head and shaft of the fibula there is a gap through which the
the toes are extended against resistance. common fibular nerve passes.
Fibularis tertius Vascular supply of lateral compartment Usually, the predomi
Attachments Fibularis tertius (peroneus tertius) often appears to be nant supply of the lateral compartment muscles is derived from
part of extensor digitorum longus and might be described as its ‘fifth branches of the anterior tibial artery; the superior is commonly the
tendon’. The muscle fibres of fibularis tertius arise from the distal third larger. There is also a lesser, variable, contribution from the fibular
or more of the medial surface of the fibula, the adjoining anterior artery in the distal part of the leg. A fibular branch may replace the
surface of the interosseous membrane, and the anterior intermuscular inferior branch of the anterior tibial artery; less commonly, the fibular
septum. The tendon passes deep to the superior extensor retinaculum artery provides the main supply to the whole compartment. The upper
and within the loop of the inferior extensor retinaculum alongside the part of fibularis longus is also supplied by the circumflex fibular branch
extensor digitorum longus (see Figs 83.6B, 84.2A). It is inserted on to of the posterior tibial artery, which is usually a branch of the anterior
the medial part of the dorsal surface of the base of the fifth metatarsal; tibial artery. The companion artery to the common fibular nerve, a
a thin expansion usually extends forwards along the medial border of branch of the popliteal artery, provides a minor contribution proxi
the shaft of the bone. mally. Distally, the tendons are supplied by the fibular perforating,
anterior lateral malleolar, lateral calcaneal, lateral tarsal, arcuate, lateral
Relations Fibularis tertius lies lateral to extensor digitorum longus. and medial plantar arteries (see Fig. 84.9).
Vascular supply Fibularis tertius is supplied by the same vessels as Innervation Fibularis longus is innervated by the superficial fibular
extensor digitorum longus. In the foot it receives an additional supply nerve, L5, S1.
from the termination of the arcuate artery and the fourth dorsal meta
tarsal artery. Actions There is little doubt that fibularis longus can evert the foot
and plantar flex the ankle, and possibly act on the leg from its distal
Innervation Fibularis tertius is innervated by the deep fibular nerve, attachments. The oblique direction of its tendon across the sole also
L5, S1. enables it to support the longitudinal and transverse arches of the foot.
With the foot off the ground, eversion is visually and palpably associ
Actions Electromyographic studies show that during the swing phase ated with increased prominence of both tendon and muscle. It is not
of gait (see Fig. 84.27), fibularis tertius acts with extensor digitorum clear to what extent this helps to maintain plantigrade contact of the
longus and tibialis anterior to produce dorsiflexion of the foot, and with foot in normal standing, but electromyographic recordings show little
fibularis longus and fibularis brevis to effect eversion of the foot (Jungers or no fibular activity under these conditions. Fibularis longus and brevis
et al 1993). This levels the foot and helps the toes to clear the ground, come strongly into action to maintain the concavity of the foot during
an action that improves the efficiency and enhances the economy of toeoff and tiptoeing. If the subject deliberately sways to one side,
bipedal locomotion. Fibularis tertius is not active during the stance fibularis longus and brevis contract on that side, but their involvement
phase, a finding that is at variance with the suggestion that the muscle in influencing postural interactions between the foot and leg remains
acts primarily to support the lateral longitudinal arch and to transfer uncertain.
the centre of pressure of the foot medially.
Testing Fibularis longus and brevis are tested together by eversion of
Testing Fibularis tertius cannot be tested in isolation, but its tendon the foot against resistance; the tendons can be identified laterally at the
can sometimes be seen and felt when the foot is dorsiflexed against ankle and in the foot.
resistance.
Fibularis brevis
Attachments Fibularis brevis arises from the distal twothirds of the
LATERAL (FIBULAR OR PERONEAL) COMPARTMENT lateral surface of the fibula, anterior to fibularis longus, and from the
anterior and posterior crural intermuscular septa. It passes vertically
The lateral compartment contains fibularis (peroneus) longus and fibu downwards and ends in a tendon that passes behind the lateral malleo
laris (peroneus) brevis (see Figs 83.2A, B, 83.6A, B). Both muscles evert lus together with, and anterior to, that of fibularis longus. The two
the foot and are plantar flexors of the ankle, and both probably play a tendons run deep to the superior fibular retinaculum in a common
part in balancing the leg on the foot in standing and walking. synovial sheath. The tendon of fibularis brevis then runs forwards on
the lateral side of the calcaneus above the fibular trochlea and the
Fibularis longus tendon of fibularis longus, and is inserted into a tuberosity on the
Attachments Fibularis longus is the more superficial of the two lateral side of the base of the fifth metatarsal.
muscles of the lateral compartment. It arises from the head and proxi
mal twothirds of the lateral surface of the fibula, the deep surface of Relations Anteriorly lie extensor digitorum longus and fibularis ter
the deep fascia, the anterior and posterior intermuscular septa, and tius. Fibularis longus and flexor hallucis longus are posterior. On the
occasionally by a few fibres from the lateral condyle of the tibia. The lateral surface of the calcaneus, the tendons of fibularis longus and fibu
muscle belly ends in a long tendon that runs distally behind the lateral laris brevis occupy separate osteofascial canals formed by the calcaneus
malleolus in a groove it shares with the tendon of fibularis brevis. The and the inferior fibular retinaculum; each tendon is enveloped in a sepa
groove is converted into a canal by the superior fibular retinaculum, so rate distal prolongation of the common synovial sheath (see Fig. 84.2A).
that the tendon of fibularis longus and that of fibularis brevis, which
lies in front of the longus tendon, are contained in a common synovial Vascular supply See ‘Fibularis longus’.
sheath. If the fibular retinaculum is ruptured by injury and fails to heal,
the tendons can dislocate from the groove. The fibularis longus tendon Innervation Fibularis brevis is innervated by the superficial fibular
runs obliquely forwards on the lateral side of the calcaneus, below the nerve, L5, S1.
fibular trochlea and the tendon of fibularis brevis, and deep to the
inferior fibular retinaculum. It crosses the lateral side of the cuboid and Actions Fibularis brevis may limit inversion of the foot and so relieve
then runs under the cuboid in a groove that is converted into a canal strain on the ligaments that are tightened by this movement (the lateral
by the long plantar ligament (see Fig. 84.20). It crosses the sole of the part of interosseous talocalcaneal, lateral talocalcaneal and calcaneo
foot obliquely and is attached by two slips, one to the lateral side of fibular ligaments). It participates in eversion of the foot and may help
the base of the first metatarsal and one to the lateral aspect of the medial to steady the leg on the foot. See also ‘Fibularis longus’.
cuneiform; occasionally, a third slip is attached to the base of the second
metatarsal. The tendon changes direction below the lateral malleolus Testing See ‘Fibularis longus’. | 1,929 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Variants of fibular muscles
Tendinous slips from fibularis longus may extend to the base of the
Biceps femoris Gastrocnemius, medial head
third, fourth or fifth metatarsals, or to adductor hallucis. Fusion of
fibularis longus and brevis has been reported but is rare. Fibularis tertius Semimembranosus
is highly variable in its form and bulk but is seldom completely absent; Gastrocnemius,
its distal attachment may be to the fourth metatarsal rather than the lateral head
Medial subtendinous
fifth. Two other variant fibular muscles, arising from the fibula between bursa of gastrocnemius
fibularis longus and fibularis brevis, have been described. These are Semimembranosus bursa
fibularis accessorius, whose tendon joins that of fibularis longus in the
sole, and fibularis quartus, which arises posteriorly and inserts on to Popliteal artery Oblique popliteal ligament
and vein; tendinous
the calcaneus or on to the cuboid.
arch of soleus
POSTERIOR (FLEXOR) COMPARTMENT Plantaris
The muscles in the posterior compartment of the lower leg form super
ficial and deep groups, separated by the transverse intermuscular septum.
Superficial flexor group
Soleus
The superficial muscles – gastrocnemius, plantaris and soleus (Fig.
83.8; see Figs 83.2A, 82.3) – form the bulk of the calf. Gastrocnemius
and soleus, collectively known as the triceps surae, constitute a powerful
muscular mass whose main function is plantar flexion of the foot,
although soleus in particular has an important postural role (see Tendon of plantaris
below). Their large size is a defining human characteristic, and is related
to the upright stance and bipedal locomotion of the human. Gastroc Gastrocnemius
nemius and plantaris act on both the knee and the ankle joints, soleus
on the latter alone.
Gastrocnemius
Attachments Gastrocnemius is the most superficial muscle of the Fibularis longus
group and forms the ‘belly’ of the calf (see Fig. 82.3). It arises by two
heads, connected to the condyles of the femur by strong, flat tendons.
The medial, larger head is attached to a depression at the upper and
posterior part of the medial condyle behind the adductor tubercle, and
to a slightly raised area on the popliteal surface of the femur just above
the medial condyle. The lateral head is attached to a recognizable area
Flexor hallucis longus
on the lateral surface of the lateral condyle and to the lower part of the
corresponding supracondylar line. Both heads also arise from subjacent
areas of the capsule of the knee joint. The tendinous attachments
Flexor digitorum longus
expand to cover the posterior surface of each head with an aponeurosis,
from the anterior surface of which the muscle fibres arise. The fleshy
part of the muscle extends to about midcalf. The muscle fibres of the
Tibialis posterior
larger medial head extend lower than those of the lateral head. As the
muscle descends, the muscle fibres begin to insert into a broad aponeu
rosis that develops on its anterior surface; up to this point, the muscular Medial malleolus
masses of the two heads remain separate. The aponeurosis gradually Superior fibular
retinaculum
narrows and receives the tendon of soleus on its deep surface to form Calcaneal tendon
the calcaneal tendon (for a detailed description of the calcaneal tendon,
see page 1440). Flexor retinaculum
On occasion, the lateral head, or the whole muscle, is absent. A third
head arising from the popliteal surface of the femur is sometimes
present.
Relations Proximally, the two heads of gastrocnemius form the lower
boundaries of the popliteal fossa. The lateral head is partially overlaid
by the tendon of biceps femoris, the medial head by semimembrano
sus. Over the rest of its length, the muscle is superficial and the two Fig. 83.8 Muscles of the left leg, posterior aspect. Gastrocnemius has
heads can easily be seen in the living subject. The superficial surface of been partially removed. (With permission from Waschke J, Paulsen F
(eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban &
the muscle is separated by the deep fascia from the short saphenous
Fischer. Copyright 2013.)
vein and the fibular communicating and sural nerves. The common
fibular nerve crosses behind the lateral head of the muscle, partly under
cover of biceps femoris. The deep surface lies posterior to the oblique muscle head with its nerve of supply, the pedicle entering the muscle
popliteal ligament, popliteus, soleus, plantaris, popliteal vessels and the near its axial border at the level of the middle of the popliteal fossa.
tibial nerve. A bursa, which communicates with the knee joint, is Medial or lateral gastrocnemius musculocutaneous flaps may be raised,
located anterior to the tendon of the medial head; if the bursa expands each based on its neurovascular pedicle. Minor accessory sural arteries
into the popliteal fossa, it does so in the plane between the medial head arise from the popliteal or from the superior genicular arteries.
of gastrocnemius and semimembranosus. The tendon of the lateral The blood supply to the calcaneal tendon is described on page 1440.
head frequently contains a sesamoid bone, the fabella, where it moves
over the lateral femoral condyle. A sesamoid bone may occasionally Innervation Gastrocnemius is innervated by the tibial nerve, S1
occur in the tendon of the medial head. and S2.
Vascular supply Each head of gastrocnemius is supplied by its own Actions The action of gastrocnemius is considered with soleus.
sural artery. These arteries are branches of the popliteal artery and arise
at variable levels, usually at the level of the tibiofemoral joint line. The Testing Gastrocnemius is tested by plantar flexion of the foot against
medial sural artery almost always arises more proximally than the resistance, in the supine position and with the knee extended. Plantar
lateral; the medial may arise proximal to the joint line, the lateral flexion (gastrocnemius and soleus) is best tested by asking the subject
sometimes distal to the line. Each sural artery enters the corresponding to perform repetitive unilateral toe rises. | 1,930 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Plantaris proportion of this type of fibre in soleus approaches 100%. However,
Attachments Plantaris arises from the lower part of the lateral supra such a rigid separation of functional roles seems unlikely in humans;
soleus probably participates in locomotion, and gastrocnemius in
condylar line and the oblique popliteal ligament (see Fig. 83.8). Its
posture. Nevertheless, the ankle joint is loosepacked in the erect
small fusiform belly is 7–10 cm long and ends in a long slender tendon,
posture, and since the weight of the body acts through a vertical line
which crosses obliquely, in an inferomedial direction, between gastroc
that passes anterior to the joint, a strong brace is required behind the
nemius and soleus, then runs distally along the medial border of the
joint to maintain stability. Electromyography shows that these forces
calcaneal tendon and inserts on to the calcaneus just medial to the cal
are supplied mainly by soleus; during symmetrical standing, soleus is
caneal tendon. Occasionally, it ends by fusing with the calcaneal tendon.
continuously active, whereas gastrocnemius is recruited only intermit
The muscle is sometimes double, and occasionally absent. Occasion
tently. The relative contributions of soleus and gastrocnemius to phasic
ally, its tendon merges with the flexor retinaculum or with the fascia of
activity of the triceps surae in walking have yet to be satisfactorily
the leg.
analysed.
Vascular supply Plantaris is supplied superficially by the lateral sural
Deep flexor group
and popliteal arteries, and deeply by the superior lateral genicular
artery. The distal tendon shares a blood supply with the calcaneal
tendon. The deep flexor group (see Fig. 83.2A, B; Figs 83.9–83.10) lies beneath
(anterior to) the transverse intermuscular septum and consists of pop
Innervation Plantaris is innervated by the tibial nerve, often from the liteus, which acts on the knee joint, and flexor digitorum longus, flexor
ramus that supplies the lateral head of gastrocnemius, S1 and S2. hallucis longus and tibialis posterior, which all produce plantar flexion
at the ankle in addition to their specific actions on joints of the foot
Actions In many mammals, plantaris is well developed and inserts and digits.
directly or indirectly into the plantar aponeurosis. In humans, the
Popliteus
muscle is almost vestigial and is normally inserted well short of the
plantar aponeurosis, usually into the calcaneus. It is therefore presumed Popliteus is described on page 1397.
to act with gastrocnemius.
Flexor digitorum longus
Soleus Attachments Flexor digitorum longus is thin and tapered proximally,
Attachments Soleus is a broad, flat muscle situated immediately but widens gradually as it descends (see Figs 83.9A, B). It arises from
deep (anterior) to gastrocnemius (see Fig. 83.8). It arises from the the posterior surface of the tibia medial to tibialis posterior from just
posterior surface of the head and proximal quarter of the shaft of the below the soleal line to within 7 or 8 cm of the distal end of the bone;
fibula; the soleal line and the middle third of the medial border of the it also arises from the fascia covering tibialis posterior. The muscle ends
tibia; and from a fibrous band between the tibia and fibula (tendinous in a tendon that extends along almost the whole of its posterior surface.
arch of the soleus) that arches over the popliteal vessels and tibial nerve. The tendon gradually crosses tibialis posterior on its superficial aspect
This origin is aponeurotic; most of the muscular fibres arise from its and passes behind the medial malleolus where it shares a groove with
posterior surface and pass obliquely to the tendon of insertion on the tibialis posterior, from which it is separated by a fibrous septum, i.e.
posterior surface of the muscle. Other muscle fibres arise from the each tendon occupies its own compartment lined by a synovial sheath
anterior surface of the aponeurosis. They are short, oblique and bipen (see Fig. 84.2B). The tendon of flexor digitorum longus then curves
nate in arrangement, and converge on a narrow, central intramuscular obliquely forwards and laterally, in contact with the medial side of the
tendon that merges distally with the principal tendon. The latter gradu sustentaculum tali, passes deep to the flexor retinaculum, and enters
ally becomes thicker and narrower, and joins the tendon of gastrocne the sole of the foot on the medial side of the tendon of flexor hallucis
mius to form the calcaneal tendon. The muscle is covered proximally longus. It crosses superficial to that tendon and receives a strong slip
by gastrocnemius, but below midcalf it is broader than the tendon of from it (and may also send a slip to it). The tendon of flexor digitorum
gastrocnemius and is readily accessible on either side of the tendon. longus then passes forwards as four separate tendons, one each for the
An accessory part of the muscle is sometimes present distally and second to fifth toes, deep to the tendons of flexor digitorum brevis. After
medially. It may be inserted into the calcaneal tendon, the calcaneus or giving rise to the lumbricals, it passes through the fibrous sheaths of
the flexor retinaculum. the lateral four toes. The tendons of flexor accessorius insert into the
long flexor tendons of the second, third and fourth digits; flexor hallucis
Relations The superficial surface of soleus is in contact with gastroc longus makes a variable contribution through the connecting slip men
nemius and plantaris. Its deep surface is related to flexor digitorum tioned above. The long flexor tendons of the lateral four digits are
longus, flexor hallucis longus, tibialis posterior and the posterior tibial attached to the plantar surfaces of the bases of their distal phalanges;
vessels and tibial nerve, from all of which it is separated by the trans each passes between the slips of the corresponding tendon of flexor
verse intermuscular septum of the leg. digitorum brevis at the base of the proximal phalanx.
A supplementary head of the muscle, flexor accessorius longus, with
Vascular supply Soleus is supplied by two main arteries: the supe its own tendon, may arise from the fibula, tibia or deep fascia and insert
rior arises from the popliteal artery at about the level of the soleal arch, into the main tendon or into flexor accessorius in the foot. It may send
and the inferior from the proximal part of the fibular artery or some communicating slips to tibialis anterior or to flexor hallucis longus.
times from the posterior tibial artery. A secondary supply is derived
from the lateral sural, fibular or posterior tibial vessels. Relations Flexor digitorum longus lies medial to flexor hallucis
There is a venous plexus within the muscle belly that is important longus. In the leg, its superficial surface is in contact with the transverse
physiologically as part of the muscle pump complex (see below). Patho intermuscular septum, which separates it from soleus, and distally from
logically, it is a common site of deep vein thrombosis. the posterior tibial vessels and tibial nerve. Its deep surface is related to
the tibia and to tibialis posterior. In the foot, it is covered by abductor
Innervation Soleus is innervated by two branches from the tibial hallucis and flexor digitorum brevis, and it crosses superficial to flexor
nerve, S1 and S2. hallucis longus.
Actions See ‘Triceps surae’. Vascular supply A series of transversely running branches of the
posterior tibial artery enters the lateral border of flexor digitorum
Testing Soleus is tested by plantar flexion of the foot against resistance longus. There may be a secondary supply from fibular branches to flexor
in the supine position, with hip and knee flexed; the muscle belly can hallucis longus. The tendons are supplied by the vessels of the ankle
be palpated separately from those of gastrocnemius. and sole of the foot.
Actions of triceps surae Innervation Flexor digitorum longus is innervated by branches of the
Gastrocnemius and soleus are the chief plantar flexors of the foot; gas tibial nerve, L5, S1 and S2.
trocnemius is also a flexor of the knee. The muscles are usually large
and correspondingly powerful. Gastrocnemius provides force for pro Actions See ‘Flexor hallucis longus’.
pulsion in walking, running and leaping. Soleus, acting from below, is
said to be more concerned with steadying the leg on the foot in stand Testing Flexor digitorum longus is tested by flexing the toes against
ing. This postural role is also suggested by its high content of slow, resistance. Aberrant function of flexor digitorum longus is implicated
fatigueresistant (type 1) muscle fibres. In many adult mammals, the in toe deformities such as hammer toe, claw toe and mallet toe. Its | 1,931 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Muscles
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RETPAHC
A B
Femur, popliteal surface
Gastrocnemius,
Biceps femoris medial head
Medial subtendinous
Gastrocnemius, bursa of gastrocnemius
lateral head
Bursa of semimembranosus Plantaris
Plantaris
Tendon of semimembranosus
Popliteus
Oblique popliteal ligament
Tendon of
Popliteus biceps femoris
Subpopliteal
recess
Tibialis posterior
Soleus
Fibula, Tibia
interosseous
border
Tibialis posterior
Flexor digitorum longus
Flexor digitorum longus (cut)
Fibularis longus
Flexor hallucis longus
Flexor hallucis
longus
Flexor digitorum longus
Flexor hallucis longus
Tibia Flexor digitorum longus (cut)
Fibularis brevis
Tibialis posterior
Flexor retinaculum
Superior fibular
retinaculum
Calcaneal tendon
Fig. 83.9 Muscles of the left leg, posterior aspect. A, The superficial muscles have been extensively removed. B, The superficial muscles have been
extensively removed, popliteus has been sectioned and the tendon of flexor digitorum longus removed as it crosses the tendon of tibialis posterior. (With
permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
tendon may be used in transfer procedures for the surgical treatment of the calcaneus (see Fig. 84.2B). Fibrous bands convert the grooves on
tibialis posterior tendon dysfunction. the talus and calcaneus into a canal lined by a synovial sheath. In
dancers, overuse causes thickening of the tendon in this region, and
Flexor hallucis longus
pain and even ‘triggering’ can occur (hallux saltans). In the sole of the
Attachments Flexor hallucis longus arises from the distal twothirds foot, the tendon of flexor hallucis longus passes forwards in the second
of the posterior surface of the fibula (except for the lowest 2.5 cm of layer like a bowstring. It crosses the tendon of flexor digitorum longus
this surface); the adjacent interosseous membrane and the posterior from lateral to medial, curving obliquely superior to it. At the crossing
crural intermuscular septum; and from the fascia covering tibialis pos point (knot of Henry), it gives off two strong slips to the medial two
terior, which it overlaps to a considerable extent (see Fig. 83.9). Its fibres divisions of the tendons of flexor digitorum longus and then crosses
pass obliquely down to a tendon that occupies nearly the whole length the lateral part of flexor hallucis brevis to reach the interval between
of the posterior aspect of the muscle. This tendon grooves the posterior the sesamoid bones under the head of the first metatarsal. It continues
surface of the lower end of the tibia, then, successively, the posterior on the plantar aspect of the hallux, and runs in an osseoaponeurotic
surface of the talus and the inferior surface of the sustentaculum tali of tunnel to be attached to the plantar aspect of the base of the distal | 1,932 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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NOITCES
Anterior tibial artery hallucis longus and flexor digitorum longus, and is overlapped by both,
but especially by the former. Its proximal attachment consists of two
Extensor digitorum
Deep fibular nerve longus tapered processes, separated by an angular interval that is traversed by
the anterior tibial vessels. The medial process arises from the posterior
Extensor hallucis surface of the interosseous membrane, except at its most distal part, and
Tibialis anterior longus
from a lateral area on the posterior surface of the tibia between the
Superficial fibular soleal line above and the junction of the middle and lower thirds of
Tibia nerve the shaft below. The lateral part arises from a medial strip of the pos
terior fibular surface in its upper twothirds. The muscle also arises from
Saphenous nerve Fibularis tertius
the transverse intermuscular septum, and from the intermuscular septa
Long saphenous
Fibula that separate it from adjacent muscles. In the distal quarter of the leg,
vein
its tendon passes deep to that of flexor digitorum longus, with which
Perforating branch it shares a groove behind the medial malleolus, each enclosed in a
of fibular artery
separate synovial sheath (see Fig. 84.2B). It then passes deep to the
Tibialis posterior flexor retinaculum and superficial to the deltoid ligament to enter the
foot. In the foot, it is at first inferior to the plantar calcaneonavicular
Fibular artery
Flexor digitorum ligament, where it contains a sesamoid fibrocartilage. The tendon then
longus Fibularis longus divides into two. The more superficial and larger division, which is a
direct continuation of the tendon, is attached to the tuberosity of the
Fibularis brevis
Posterior tibial navicular, from which fibres continue to the inferior surface of the
artery Flexor hallucis medial cuneiform. A tendinous band also passes laterally and a little
longus
proximally to the tip and distal margin of the sustentaculum tali. The
Tibial nerve Sural nerve deeper lateral division gives rise to the tendon of origin of the medial
Plantaris Small saphenous limb of flexor hallucis brevis, and then continues between this muscle
vein and the navicular and medial cuneiform to end on the intermediate
Calcaneal tendon Soleus
cuneiform and the bases of the second, third and fourth metatarsals;
Fig. 83.10 A transverse section through the left leg, approximately 6 cm
the slip to the fourth metatarsal is the strongest.
proximal to the medial malleolus.
The slips to the metatarsals vary in number. Slips to the cuboid and
lateral cuneiform may also occur. An additional muscle, the tibialis
phalanx. The tendon is retained in position over the lateral part of flexor secundus, has been described running from the back of the tibia to the
hallucis brevis by the diverging stems of the distal band of the medial capsule of the ankle joint.
intermuscular septum.
The distal extent of the muscle belly is a distinctive characteristic; in Relations The superficial surface of tibialis posterior is separated from
the posteromedial surgical approach to the ankle, flexor hallucis longus soleus by the transverse intermuscular septum, and is related to flexor
is readily identifiable by the fact that muscle fibres are evident almost digitorum longus, flexor hallucis longus, the posterior tibial vessels, the
to calcaneal level. In athletes, the muscle fibres may be present so far tibial nerve and the fibular vessels. The deep surface is in contact with
inferiorly into the tendon as to be susceptible to impingement when the interosseous membrane, tibia, fibula and ankle joint.
pulled into the tunnel at the talus.
The connecting slip to flexor digitorum longus varies in size; it Vascular supply Tibialis posterior is supplied by numerous branches
usually continues into the tendons for the second and third toes but is of small calibre arising from the posterior tibial and fibular arteries. The
sometimes restricted to the second toe and occasionally extends to the tendon is supplied by arteries of the medial malleolar network and by
fourth toe. the medial plantar artery.
Relations Soleus and the calcaneal tendon lie superficial (i.e. poste Innervation Tibialis posterior is innervated by the tibial nerve, L4
rior) to flexor hallucis longus, separated by the transverse intermuscular and L5.
septum. Deeply situated are the fibula, tibialis posterior, fibular vessels,
distal part of the interosseous membrane and the talocrural joint. Lat Actions Tibialis posterior is a powerful muscle that, on contraction,
erally lie fibularis longus and fibularis brevis; medially are tibialis pos has an excursion of only 1–2 cm. It is the principal invertor of the
terior, posterior tibial vessels and the tibial nerve. Flexor hallucis longus foot and also initiates elevation of the heel; it is responsible for the
is an important surgical landmark at the ankle; staying lateral to it hindfoot varus that occurs during a single heel raise. Due to its inser
prevents injury to the neurovascular bundle. tions on to the cuneiforms and the bases of the metatarsals, it has
long been thought to assist in elevating the longitudinal arch of the
Vascular supply Flexor hallucis longus is supplied by numerous
foot, although electromyography shows that it is actually quiescent in
branches of the fibular artery. The tendon is supplied by arteries of the
standing. It is phasically active in walking, during which it probably
ankle and foot.
acts with the intrinsic foot musculature and the lateral leg muscles to
control the degree of pronation of the foot and the distribution of
Innervation Flexor hallucis longus is innervated by branches of the
weight through the metatarsal heads. It is said that when the body is
tibial nerve, L5, S1 and S2 (mainly S1).
supported on one leg, the invertor action of tibialis posterior, exerted
Testing Flexor hallucis longus is tested by flexion of the hallux against from below, helps to maintain balance by resisting any tendency to
sway laterally.
resistance.
Tibialis posterior is also important in the maintenance of the medial
Actions of deep digital flexors part of the longitudinal arch of the foot. In overweight individuals with
Both flexor hallucis longus and flexor digitorum longus can act as pes planus (flat foot deformity), unaccustomed activity can result in
plantar flexors but this action is weak compared with that of gastrocne inflammation and degeneration of the terminal portion of the tendon,
mius and soleus. When the foot is off the ground, both muscles flex the which leads to elongation of the tendon, attenuation of the spring liga
phalanges, acting primarily on the distal phalanges. When the foot is ment and progressive collapse of the medial longitudinal arch. As the
on the ground and under load, they act synergistically with the small excursion is so short, the muscle cannot compensate for the lengthen
muscles of the foot and, especially in the case of flexor digitorum ing of its tendon, a failure that results in tibialis posterior tendon
longus, with the lumbricals and interossei to maintain the pads of the dysfunction.
toes in firm contact with the ground, enlarging the weightbearing area
and helping to stabilize the heads of the metatarsals, which form the Testing Tibialis posterior is tested by asking the subject to move the
fulcrum on which the body is propelled forwards. Activity in the long foot into a position of maximal plantar flexion and inversion against
digital flexors is minimal during quiet standing, so they apparently the resistance of the examiner’s hand; the tendon can be seen and felt
contribute little to the static maintenance of the longitudinal arch, but just proximal to the medial malleolus. Testing tibialis posterior function
they become very active during toeoff and tiptoe movements. is important in establishing a diagnosis of a common fibular nerve
neuropathy and differentiating it from an L5 radiculopathy, which are
Tibialis posterior
two common clinical conditions. In a common fibular nerve neur
Attachments Tibialis posterior is the most deeply placed muscle of opathy, tibialis posterior has normal function, whereas in an L5 radicul
the flexor group (see Fig. 83.9). At its origin it lies between flexor opathy, tibialis posterior is weak. | 1,933 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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ankle joint. Proximally, it lies between tibialis anterior and extensor
VASCULAR SUPPLY
digitorum longus, then between tibialis anterior and extensor hallucis
longus. At the ankle it is crossed superficially from the lateral side by
ARTERIES the tendon of extensor hallucis longus and then lies between this
tendon and the first tendon of extensor digitorum longus. Its proximal
Anterior tibial artery twothirds are covered by adjoining muscles and deep fascia, its distal
third by the skin, fasciae and extensor retinacula. It is accompanied by
The anterior tibial artery arises at the distal border of popliteus (Fig. venae comitantes. The deep fibular nerve, curling laterally round the
83.11; see Figs 78.4A, B, 83.7, 83.10, 82.1, 82.4, 84.9). At first in the fibular neck, reaches the lateral side of the artery where it enters the
flexor compartment, it passes between the heads of tibialis posterior extensor region, is then anterior to the artery in the middle third of
and through the oval aperture in the proximal part of the interosseous the leg, and becomes lateral again distally.
membrane to reach the extensor (anterior) compartment, passing
Branches
medial to the fibular neck; it is vulnerable here during tibial osteotomy.
Descending on the anterior aspect of the membrane, it approaches the The named branches of the anterior tibial artery are the posterior and
tibia and, distally, lies anterior to it. At the ankle, the anterior tibial anterior tibial recurrent, muscular, perforating, and anterior medial and
artery is located approximately midway between the malleoli, and it lateral malleolar arteries.
continues on the dorsum of the foot, lateral to extensor hallucis longus,
as the dorsalis pedis artery. Posterior tibial recurrent artery The posterior tibial recurrent
The anterior tibial artery may, on occasion, be small but it is rarely artery is an inconstant branch that arises before the anterior tibial artery
absent. Its function may be replaced by perforating branches from the reaches the extensor compartment of the leg. It ascends anterior to
posterior tibial artery or by the perforating branch of the fibular artery. popliteus, anastomosing with the inferior genicular branches of the
It occasionally deviates laterally, regaining its usual position at the popliteal artery. It supplies the superior tibiofibular joint.
ankle. It may also be larger than normal, in which case its territory of
supply in the foot may be increased to include the plantar surface. Anterior tibial recurrent artery The anterior tibial recurrent artery
arises near the posterior tibial recurrent artery. It ascends in tibialis
Relations anterior, ramifies on the front and sides of the knee joint, and joins the
In its proximal twothirds the anterior tibial artery lies on the interos patellar anastomosis, which interconnects with the genicular branches
seous membrane, and in its distal third it is anterior to the tibia and of the popliteal and circumflex fibular arteries.
Aorta Muscular branches Numerous branches supply the adjacent
muscles. Some then pierce the deep fascia to supply the skin, while
Common iliac artery others traverse the interosseous membrane to anastomose with branches
Internal iliac artery of the posterior tibial and fibular arteries.
External iliac artery Perforating branches Most of the fasciocutaneous perforators pass
along the anterior fibular fascial septum behind extensor digitorum
longus before penetrating the deep fascia to supply the skin.
Anterior medial malleolar artery The anterior medial malleolar
artery arises approximately 5 cm proximal to the ankle. It passes pos
terior to the tendons of extensor hallucis longus and tibialis anterior
medial to the joint, where it joins branches of the posterior tibial and
Profunda femoris artery
medial plantar arteries.
Anterior lateral malleolar artery The anterior lateral malleolar
artery runs posterior to the tendons of extensor digitorum longus and
fibularis tertius to the lateral side of the ankle and anastomoses with
Femoral artery the perforating branch of the fibular artery and ascending branches of
the lateral tarsal artery.
Posterior tibial artery
The posterior tibial artery begins at the distal border of popliteus,
between the tibia and fibula (see Figs 78.4B, 82.4, 83.11). It descends
medially in the flexor compartment and divides under abductor hal
lucis, midway between the medial malleolus and the calcaneal tubercle,
into the medial and lateral plantar arteries. The artery may be much
reduced in length or in calibre; the fibular artery then takes over its
Anterior tibial artery distal territory of supply and may consequently be increased in size.
Relations
Posterior tibial artery
The posterior tibial artery is successively posterior to tibialis posterior,
flexor digitorum longus, the tibia and the ankle joint. Proximally, gas
trocnemius, soleus and the transverse intermuscular septum of the leg
are superficial to the artery, and distally, it is covered only by skin and
fascia. It is parallel with and approximately 2.5 cm anterior to the
medial border of the calcaneal tendon; terminally, it is deep to the flexor
retinaculum. The artery is accompanied by two veins and the tibial
nerve. The nerve is at first medial to the artery but soon crosses behind
it and subsequently becomes largely posterolateral in position.
Branches
The named branches of the posterior tibial artery are the circumflex
fibular, nutrient, muscular, perforating, communicating, medial malle
olar, calcaneal, lateral and medial plantar, and fibular arteries.
Fig. 83.11 Three-dimensional CT imaging illustrating the arterial supply of Circumflex fibular artery The circumflex fibular artery, which
the lower limb. Note the relationships of the arteries to the surrounding sometimes arises from the anterior tibial artery, passes laterally round
bones. (Courtesy of Dr Yoginder Vaid and Mr Jon C Betts, Jr.) the neck of the fibula through the soleus to anastomose with the | 1,934 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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inferior medial and lateral genicular and anterior tibial recurrent arter Figs 78.4B, 82.4, 83.2, 83.10). Reaching the inferior tibiofibular syn
ies. It supplies bone and related articular structures. desmosis, it divides into calcaneal branches that ramify on the lateral
and posterior surfaces of the calcaneus. Proximally, it is covered by
Nutrient artery of the tibia The nutrient artery of the tibia arises soleus and the transverse intermuscular septum between soleus and the
from the posterior tibia near its origin. After giving off a few muscular deep muscles of the leg, and distally it is overlapped by flexor hallucis
branches, it descends into the bone immediately distal to the soleal longus.
line. It is one of the largest of the nutrient arteries. The fibular artery may branch high from the posterior tibial artery
or may even branch from the popliteal artery separately, resulting in a
Muscular branches Muscular branches are distributed to the soleus true ‘trifurcation’. It may also branch more distally from the posterior
and deep flexors of the leg. tibial artery, sometimes 7 or 8 cm distal to popliteus. Its size tends to
be inversely related to the size of the other arteries of the leg. It may be
Perforating branches Approximately five fasciocutaneous perfor reduced in size but is more often enlarged, when it may join, reinforce
ators emerge between flexor digitorum longus and soleus, and pass or even replace the posterior tibial artery in the distal leg and foot.
through the deep fascia, often accompanying the perforating veins that
connect the deep and superficial venous systems. The arterial perfor Branches
ators then divide into anterior and posterior branches to supply the The fibular artery has muscular, nutrient, perforating, communicating
regional periosteum and skin. These vessels are utilized in raising and calcaneal branches.
medial fasciocutaneous perforator flaps in the leg.
Muscular branches Multiple short branches supply soleus, tibialis
Communicating branch The communicating branch runs posteri posterior, flexor hallucis longus and the fibular muscles.
orly across the tibia approximately 5 cm above its distal end, deep to
flexor hallucis longus, to join a communicating branch of the fibular Nutrient artery The nutrient artery branches from the main trunk
artery. approximately 7 cm from its origin and enters the fibula 14–19 cm
from the apex of the head of the fibula.
Medial malleolar branches The medial malleolar branches pass
round the medial malleolus to the medial malleolar network, which Perforating branches The main perforating branch traverses the
supplies the skin. interosseous membrane approximately 5 cm proximal to the lateral
malleolus to enter the extensor compartment, where it anastomoses
Calcaneal branches Calcaneal branches arise just proximal to the with the anterior lateral malleolar artery. Descending anterior to the
terminal division of the posterior tibial artery. They pierce the flexor inferior tibiofibular syndesmosis, it supplies the tarsus and anastomoses
retinaculum to supply fat and skin behind the calcaneal tendon and in with the lateral tarsal artery. This branch is sometimes enlarged and may
the heel, and muscles on the tibial side of the sole; the branches anas replace the dorsalis pedis artery.
tomose with medial malleolar arteries and calcaneal branches of the Fasciocutaneous perforators from the lateral muscular branches pass
fibular artery. along the posterior fibular fascial septum to penetrate the deep fascia
and reach the skin. These vessels are utilized in raising fasciocutaneous
Medial plantar artery posterolateral leg flaps (see below).
Communicating branch The communicating branch connects to
The medial plantar artery is the smaller terminal branch of the posterior
a communicating branch of the posterior tibial artery approximately
tibial artery and passes distally along the medial side of the foot, medial
5 cm proximal to the ankle.
to the medial plantar nerve (see Figs 78.4B, 84.25). At first deep to
abductor hallucis, it runs distally between this muscle and flexor digi
Calcaneal branches Calcaneal (terminal) branches anastomose
torum brevis, and supplies both. Near the first metatarsal base, its size,
with the anterior lateral malleolar and calcaneal branches of the pos
already diminished by muscular branches, is further reduced to a super
terior tibial artery.
ficial stem that divides to form three superficial digital branches. These
accompany the digital branches of the medial plantar nerve and join
Perforator flaps in the knee and leg
the first to third plantar metatarsal arteries. The main trunk of the
The perforators, which arise from the rich vascular anastomosis around
medial plantar artery then runs on to reach the medial border of the
the patella, generally traverse the tendon of quadriceps femoris to
hallux, where it anastomoses with a branch of the first plantar metatar
supply the skin over the patella and the peripatellar region (see Fig.
sal artery.
78.7). The skin flaps based on these perforators may be used as distally
based or proximally based flaps to cover defects over the knee and
Lateral plantar artery
popliteal region. The direct cutaneous branch of the popliteal artery and
a superficial sural artery, which accompanies the sural nerve, provide
The lateral plantar artery is the larger terminal branch of the posterior additional perforators to the skin over the back of the knee. The poste
tibial artery (see Figs 78.4B, 84.25). It passes distally and laterally to rior tibial artery gives off an average of ten perforators to the skin cover
the fifth metatarsal base, lateral to the lateral plantar nerve. (The medial ing the anteromedial and posterior parts of the leg. In the upper third
and lateral plantar nerves lie between the corresponding plantar arter of the leg, the perforating vessels are predominantly muscular and
ies.) Turning medially with the deep branch of the lateral plantar nerve, periosteocutaneous, while in the lower third, the perforating vessels are
it reaches the interval between the first and second metatarsal bases, mainly direct subcutaneous types. They anastomose with the perforat
and unites with the deep plantar artery to complete the plantar arch. ing branches of the anterior tibial artery anteriorly and fibular artery
As it passes laterally, it is first between the calcaneus and abductor hal posteriorly. Inferiorly, the posterior tibial artery forms a rich anasto
lucis, then between flexor digitorum brevis and flexor accessorius. motic ring around the ankle joint with the fibular and anterior tibial
Running distally to the fifth metatarsal base, it passes between flexor arteries. Perforators from these vessels supply the calcaneal tendon and
digitorum brevis and abductor digiti minimi, and is covered by the the overlying skin. The posterior tibial artery gives off three direct cuta
plantar apo neurosis, superficial fascia and skin. neous perforators in the lower part of the leg; a distally based skin or
adipofascial flap based on one of these perforators may be used to
Branches
reconstruct a defect over the anterior or the posterior aspect of the lower
Muscular branches supply the adjoining muscles. Superficial branches
leg. The anterior tibial artery gives off an average of six perforators,
supply the skin and subcutaneous tissue along the lateral sole. Anasto
which supply the anterolateral part of the leg. They emerge in two
motic branches run to the lateral border of the foot, joining branches
longitudinal rows; one perforator is fairly large and accompanies the
of the lateral tarsal and arcuate arteries. A calcaneal branch sometimes
superficial fibular nerve. A small skin flap based on any one of these
pierces abductor hallucis to supply the skin of the heel.
perforators may be used to cover small defects over the tibia, and a
neurocutaneous flap that includes the superficial fibular nerve may
Fibular artery
be used.
The fibular artery has an average of five perforators. A constant
The fibular artery arises from the posterior tibial artery approximately perforator pierces the deep fascia approximately 5 cm above the
2.5 cm distal to popliteus and passes obliquely to the fibula, descend lateral malleolus and divides into an ascending and a descending
ing along its medial crest either in a fibrous canal between tibialis branch. A vascularized fibula graft based on the fibular artery is now
posterior and flexor hallucis longus or within flexor hallucis longus (see the standard graft used in reconstruction of the mandible, while small | 1,935 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Innervation
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fasciocutaneous and adipofascial flaps based on the perforators of the tibialis posterior for most of its course except distally, where it adjoins
fibular artery are useful in covering soft tissue defects over the heel and the posterior surface of the tibia. The tibial nerve ends under the flexor
proximal part of the foot. retinaculum by dividing into the medial and lateral plantar nerves.
Branches
DEEP AND SUPERFICIAL VENOUS SYSTEM
The branches of the tibial nerve are articular, muscular, sural, medial
calcaneal and medial and lateral plantar nerves. The medial and lateral
Posterior tibial veins plantar nerves and the medial calcaneal nerve are described on page
1447.
The posterior tibial veins accompany the posterior tibial artery (see Fig.
78.8). They receive tributaries from the calf muscles (especially from Articular branches Articular branches to the knee joint accompany
the venous plexus in the soleus) and connections from superficial veins the superior and inferior medial genicular arteries and the middle
and the fibular veins. genicular artery; they form a plexus with a branch from the obturator
nerve and also supply the oblique popliteal ligament. The branches
Fibular veins accompanying the superior and inferior medial genicular arteries supply
the medial part of the capsule. A branch of the nerve to popliteus (tibial
nerve) supplies the posterior portion of the superior tibiofibular joint.
The fibular veins, running with their artery, receive tributaries from
Just before the tibial nerve bifurcates, it gives off branches that supply
soleus and from superficial veins.
the ankle joint.
Anterior tibial veins
Muscular branches Proximal muscular branches arise between the
heads of gastrocnemius and supply gastrocnemius, plantaris, soleus and
The anterior tibial veins, continuations of the venae comitantes of the
popliteus. The nerve to soleus enters its superficial aspect. The branch
dorsalis pedis artery, leave the anterior compartment between the tibia
to popliteus descends obliquely across the popliteal vessels, curling
and fibula, and pass through the proximal end of the interosseous
round the distal border of the muscle to its anterior surface. It also
membrane. They unite with the posterior tibial veins to form the pop
supplies tibialis posterior, the superior tibiofibular joint and the tibia,
liteal vein at the distal border of popliteus.
and gives off an interosseous branch that descends near the fibula to
reach the distal tibiofibular joint.
Long and short saphenous veins
Muscular branches in the leg, either independently or by a common
trunk, supply soleus (on its deep surface), tibialis posterior, flexor digi
The long and short saphenous veins are described on pages 1370–1371 torum longus and flexor hallucis longus. The branch to flexor hallucis
and 1399, respectively. longus accompanies the fibular vessels.
Venous disease Sural nerve The sural nerve descends between the heads of gastroc
nemius, pierces the deep fascia proximally in the leg, and is joined at
Chronic venous disease is common. Sustained overdistension of the a variable level by the sural communicating branch of the common
superficial veins of the lower limb may result in the development of fibular nerve. Some authors term this branch the lateral sural cutaneous
short, dilated venous segments or varicosities. Varicose veins can occur nerve, and call the main trunk (from the tibial nerve) the medial sural
as a consequence of venous valve failure at the proximal end of the long cutaneous nerve. The sural nerve descends lateral to the calcaneal
saphenous vein at the saphenofemoral junction, or in the perforating tendon, near the short saphenous vein, to the region between the lateral
veins that pass from the superficial system to the highpressure deep malleolus and the calcaneus, and supplies the posterior and lateral skin
veins. Varicose veins have thin walls and ‘leak’ red blood cells into of the distal third of the leg. It then passes distal to the lateral malleolus
adjacent soft tissues. As these cells are broken down, haemosiderin is along the lateral side of the foot and fifth toe, supplying the overlying
deposited in the soft tissues, resulting in a brown pigmentation. This skin. It connects with the posterior femoral cutaneous nerve in the leg
phenomenon, together with the fact that venous stasis produces and with the superficial fibular nerve on the dorsum of the foot.
oedema, renders the soft tissues of the leg unhealthy and prone to The sural nerve is often used as an autologous peripheral nerve graft
ulceration, particularly after minor trauma. on the grounds that it is easily harvested, readily identified and exclu
Acute venous disease occurs most commonly in the posterior com sively cutaneous.
partment of the leg. This is attributed to the sluggish blood flow that
Lesions of the tibial nerve
occurs, at times, in the deep veins of the calf. This relative stasis predis
poses to the formation of venous thrombi. Fragments of these thrombi The tibial nerve is vulnerable to direct injury in the popliteal fossa,
may become dislodged and carried in the venous return to the heart to where it lies superficial to the popliteal vessels at the level of the knee,
cause a lifethreatening pulmonary embolism. Blockage of the normal or to compression at the tendinous arch of the soleus. It may be
venous system may contribute to increased local venous pressure and damaged in compartment syndrome that affects the deep flexor com
oedema. partment of the calf. The tibial nerve or the medial and lateral plantar
nerves may become entrapped beneath the flexor retinaculum or the
socalled plantar tunnels (beneath the fascia of the abductor hallucis)
INNERVATION at the ankle, resulting in tarsal tunnel syndrome.
Tibial nerve Common fibular nerve
The tibial nerve, the larger component of the sciatic nerve, is derived The common fibular nerve (common peroneal nerve) is approximately
from the ventral branches (anterior divisions) of the fourth and fifth half the size of the tibial nerve and is derived from the dorsal branches
lumbar and first to third sacral ventral rami. It descends along the back of the fourth and fifth lumbar and first and second sacral ventral rami.
of the thigh and popliteal fossa to the distal border of popliteus. It It descends obliquely along the lateral side of the popliteal fossa to the
then passes anterior to the arch of soleus with the popliteal artery and fibular head, medial to biceps femoris. It lies between the tendon of
continues into the leg. In the thigh, it is overlapped proximally by the biceps femoris, to which it is bound by fascia, and the lateral head of
hamstring muscles but it becomes more superficial in the popliteal gastrocnemius (Fig. 83.12). The nerve then passes into the anterolateral
fossa, where it is lateral to the popliteal vessels. At the level of the knee, compartment of the leg through a tight opening in the thick fascia
the tibial nerve becomes superficial to the popliteal vessels and crosses overlying tibialis anterior. It curves lateral to the fibular neck, deep to
to the medial side of the artery. In the distal popliteal fossa, it is over fibularis longus, and divides into superficial and deep fibular nerves; an
lapped by the junction of the two heads of gastrocnemius. articular trunk, derived from the deep fibular nerve, provides an articu
In the leg, the tibial nerve descends with the posterior tibial vessels lar branch that travels with the anterior tibial recurrent artery and a
to lie between the heel and the medial malleolus (see Fig. 82.4). Proxi proximal branch to tibialis anterior.
mally, it is deep to soleus and gastrocnemius, but in its distal third is
covered only by skin and fasciae, and overlapped sometimes by flexor Branches
hallucis longus. At first medial to the posterior tibial vessels, it crosses The common fibular nerve has articular and cutaneous branches, and
behind them and descends lateral to them until it bifurcates. It lies on terminates as the superficial and deep fibular nerves. | 1,936 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Leg
Common fibular nerve
Lateral sural cutaneous nerve
Deep fibular nerve
Superficial fibular nerve
Sural nerve
Superficial fibular nerve
Deep fibular nerve
Fascia of the leg
Deep fibular nerve,
cutaneous branch
Dorsal branch of plantar
Lateral calcaneal branches digital nerve of great toe
Fig. 83.12 The course, relations and branches of the right common fibular
nerve. (Courtesy of Rolfe Birch, all rights reserved, published in Birch R,
Surgical Disorders of the Peripheral Nerve. 2nd edition, 2011. Springer-
Verlag, London.)
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Articular branches There are three articular branches. Two accom to the lateral malleolus. Branches of the superficial fibular nerve supply
pany the superior and inferior lateral genicular arteries; they may arise the skin of the dorsum of all the toes except that of the lateral side of
in common. The third, the recurrent articular branch, arises near the the fifth toe (supplied by the sural nerve) and the adjoining sides of the
termination of the common fibular nerve. It ascends with the anterior great and second toes (supplied by the medial terminal branch of the
recurrent tibial artery through tibialis anterior and supplies the antero deep fibular nerve). Some of the lateral branches of the superficial
lateral part of the knee joint capsule and the proximal tibiofibular fibular nerve are frequently absent and are replaced by sural nerve
joint. branches.
Cutaneous branches The two cutaneous branches, often from a Accessory fibular nerves An accessory superficial fibular nerve
common trunk, are the lateral sural and sural communicating nerves. and an accessory deep fibular nerve have been described as variant
The lateral sural cutaneous nerve (lateral cutaneous nerve of the calf) branches of the superficial fibular nerve; both are probably the product
supplies the skin on the anterior, posterior and lateral surfaces of the of atypical branching of the parent nerve deep to the deep fascia (see
proximal leg. The sural communicating nerve arises near the head of above).
the fibula and crosses the lateral head of gastrocnemius to join the sural
Lesions of the superficial fibular nerve
nerve. It may descend separately as far as the heel.
A lesion of the superficial fibular nerve causes weakness of foot eversion
Lesions of the common fibular nerve and sensory loss on the lateral aspect of the leg that extends on to the
The common fibular nerve is relatively unprotected as it traverses the dorsum of the foot. The nerve can be subject to entrapment as it pen
lateral aspect of the neck of the fibula and is easily compressed at this etrates the deep fascia of the leg and it may also be involved in compart
site, e.g. by plaster casts or ganglia. The nerve may also become entrapped ment syndrome that affects the lateral compartment of the leg.
by a fascial band beneath fibularis longus within the socalled fibular
Deep fibular nerve
tunnel, between the attachments of fibularis longus to the head and
The deep fibular nerve (deep peroneal nerve) begins at the bifurcation
shaft of the fibula. Traction lesions can accompany dislocations of the
of the common fibular nerve, between the fibula and the proximal part
lateral compartment of the knee, and are most likely to occur if the
of fibularis longus. It passes obliquely forwards deep to extensor digi
distal attachments of biceps femoris and the ligaments that insert on
torum longus to the front of the interosseous membrane and reaches
to the fibular head are avulsed, possibly with a small part of the fibular
the anterior tibial artery in the proximal third of the leg. It descends
head; the nerve is tethered to the tendon of biceps femoris by dense
with the artery to the ankle, where it divides into lateral and medial
fascia and so is pulled proximally. Severe traction lesions may produce
terminal branches. As it descends, the nerve is first lateral to the artery,
longitudinal injuries affecting a long segment of the common fibular
then anterior, and finally lateral again at the ankle.
nerve. Torsional injury following ankle injury (sprain or fracture) may
result in common fibular neuropathy; the injury is transmitted from
Branches
the ankle along the interosseous membrane to the proximal leg (Lal
The deep fibular nerve supplies muscular branches to tibialis anterior,
ezari et al 2012). Patients with such injury present with a foot drop.
extensor hallucis longus, extensor digitorum longus and fibularis
Physical examination reveals weakness or paralysis of ankle dorsiflex
tertius, and an articular branch to the ankle joint.
ion, toe extension and eversion of the foot, but inversion and plantar
The lateral terminal branch crosses the ankle deep to extensor digi
flexion are normal. Sensation on the dorsum of the foot, including the
torum brevis, enlarges as a pseudoganglion and supplies extensor digi
first dorsal web space, is diminished. The ankle reflex is preserved. Since
torum brevis. From the enlargement, three minute interosseous
the common fibular nerve divides at the fibular neck into the superficial
branches supply the tarsal and metatarsophalangeal joints of the middle
and deep fibular nerves, injuries to the nerve at this level may damage
three toes.
either the main trunk or its branches. Electrodiagnostic studies can help
The medial terminal branch runs distally on the dorsum of the foot
localize a common fibular nerve injury to the fibular neck region. At
lateral to the dorsalis pedis artery, and connects with the medial branch
this level, nerve conduction studies may show slowed velocities and
of the superficial fibular nerve in the first interosseous space. It divides
electromyography would demonstrate denervation in the muscles
into two dorsal digital nerves, which supply adjacent sides of the great
innervated by the common fibular nerve (such as tibialis anterior or
and second toes. Before dividing, it gives off an interosseous branch,
fibularis longus), whereas more proximally innervated muscles (par
which supplies the first metatarsophalangeal joint. The deep fibular
ticularly the short head of biceps femoris) would be normal.
nerve may end as three terminal branches.
Superficial fibular nerve
Lesions of the deep fibular nerve
The superficial fibular nerve (superficial peroneal nerve) begins at the
Isolated injury to the deep fibular nerve may result from compartment
bifurcation of the common fibular nerve. It lies deep to fibularis longus
syndrome that affects the anterior compartment of the leg or from an
at first, then passes anteroinferiorly between fibularis longus and brevis
intraneural ganglion cyst (mucinous cyst within the nerve derived from
and extensor digitorum longus, and pierces the deep fascia in the distal
the superior tibiofibular joint via the articular branch that travels with
third of the leg (see Fig. 83.12). It divides into a large medial dorsal
the anterior tibial recurrent artery (Spinner et al 2003)). Individuals
cutaneous nerve and a smaller, more laterally placed, intermediate
with lesions of the deep fibular nerve have weakness of ankle dorsiflex
dorsal cutaneous nerve, usually after piercing the deep fascia, but some
ion and extension of all toes but normal foot eversion. Sensory impair
times while it is still deep to the fascia. As the nerve lies between the
ment is confined to the first interdigital web space.
muscles it supplies fibularis longus, fibularis brevis and the skin of the
lower leg. The deep course, i.e. the compartmental localization, and the
Saphenous nerve
peripheral digital distribution of the superficial fibular nerve are subject
to considerable variation (see Kosinksi’s classification; Kosinski 1926,
Solomon et al 2001). The saphenous nerve is described on page 1399.
Branches
The medial dorsal cutaneous nerve passes in front of the ankle joint
and divides into two dorsal digital branches; one of these supplies the Bonus e-book images
medial side of the hallux and the other supplies the adjacent side of
the second and third toes. It communicates with the saphenous and
deep fibular nerves. The smaller intermediate branch crosses the dorsum Fig. 83.2 C, An axial T2-weighted MRI of the leg in a patient with
of the foot laterally. It divides into dorsal digital branches that supply anterior compartment denervation.
the contiguous sides of the third to fifth toes and the skin of the lateral
aspect of the ankle, where it connects with the sural nerve. Both Fig. 83.12 The course, relations and branches of the right common
branches, especially the intermediate, are at risk during the placement fibular nerve.
of portal skin incisions for arthroscopy and during surgical approaches | 1,938 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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References
REFERENCES
Bayram H, Herdem M, Temoçin AK 1996 Fibular dimelia and mirror foot A paper that provides magnetic resonance imaging evidence to support
without associated anomalies. Clin Genet 49:311–3. the notion that coexisting ankle and common fibular nerve injuries occur
Cormack GC, Lamberty BGH 1994 The Arterial Anatomy of Skin Flaps. by translational forces distributed along the interosseous membrane of
Edinburgh: Elsevier, Churchill Livingstone. the leg.
A definitive anatomical reference on blood supply to the skin, which focuses
Oeffinger D, Conaway M, Stevenson R et al 2010 Tibial length growth curves
on using skin flaps in plastic and reconstructive surgical procedures.
for ambulatory children and adolescents with cerebral palsy. Dev Med
Eckhoff DG, Kramer RC, Watkins JJ et al 1994 Variation in tibial torsion. Child Neurol 52:e195–201.
Clin Anat 7:76–9. A study that investigates growth of the tibia in children with and without
A paper that discusses the wide variability of tibial torsion in individuals cerebral palsy.
and populations.
Pritchett JW, Bortel DT 1997 Single bone straight line graphs for the lower
Ganey TM, Carey TP, O’Neal ML, Ogden JA 2000 Morphologic and radio extremity. Clin Orthop Relat Res 342:132–40.
graphic characterization of fibular dimelia. J Pediatr Orthop B 9: Presents a method for the accurate prediction of growth for the femur and
293–305. tibia.
Jungers WL, Meldrum DJ, Stern JT Jr 1993 The functional and evolutionary Solomon LB, Ferris L, Tedman R et al 2001 Surgical anatomy of the sural
significance of the human peroneus tertius muscle. J Hum Evol 25: and superficial fibular nerves with an emphasis on the approach to the
377–86. lateral malleolus. J Anat 199:717–23.
A paper that discusses the functional role of peroneus tertius in human gait, A study that calls attention to the vulnerability of the sural and superficial
compared to non-human primates in whom this muscle is lacking. fibular nerves during approaches to the lateral malleolus.
Kärrholm J, Hansson LI, Selvik G 1984 Longitudinal growth rate of the distal
Spinner RJ, Atkinson JL, Tiel RL 2003 Peroneal intraneural ganglia: the
tibia and fibula in children. Clin Orthop Relat Res 191:121–8.
importance of the articular branch. A unifying theory. J Neurosurg 99:
A radiological study of the growth rates of the distal tibia and fibula in
330–43.
children.
A paper that provides layers of anatomical and pathological evidence to
Kosinski C 1926 The course, mutual relations and distribution of the cutan substantiate a unifying articular theory explaining all cases of intraneural
eous nerves of the metazonal regions of the leg and foot. J Anat Physiol ganglion cysts.
60:274–97.
Taylor GI, Razaboni RM (eds) 1994 Michael Salmon: Anatomic Studies.
A paper that describes the relations, distributions and variations of the
Book 1, Arteries of the Muscles of the Extremities and the Trunk.
cutaneous nerves of the leg and foot.
St Louis: Quality Medical Publishing.
Kristiansen LP, Gunderson RB, Steen H et al 2001 The normal development A translated, edited version of a classic French text, first published in 1933.
of tibial torsion. Skeletal Radiol 30:519–22. Now a major source book in plastic surgery.
A study that uses computed tomography to elucidate the normal
Tubbs RS, Apaydin N, Uz A et al 2009 The clinical anatomy of the ligament
development of tibial torsion in adults and children. The authors conclude
of Barkow at the proximal tibiofibular joint. Surg Radiol Anat 31:
that tibial torsion in children mainly develops during the first four years of life.
161–3.
Lalezari S, Amrami KK, Tubbs RS et al 2012 Interosseous membrane: the A first-of-its-kind study aimed at examining the anatomy of the so-called
anatomic basis for combined ankle and common fibular (peroneal) ligament of Barkow at the proximal tibiofibular joint. The ligament was
nerve injuries. Clin Anat 25:401–6. observed in the majority of specimens and was ossified in one. | 1,939 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
CHAPTER
84
Ankle and foot
The ankle joint (talocrural joint) is a diarthrodial articulation involving 78.14). Innervation of the dorsum of the foot is provided medially by
the distal tibia and fibula and the body of the talus; it is the only the saphenous nerve, centrally by the superficial fibular nerve, and lat
example in the human body of a true mortise joint. The human foot is erally by the sural nerve; the deep fibular nerve supplies the dorsum of
a complex structure adapted to allow orthograde bipedal stance and the first web space. Dorsal branches of the medial and lateral plantar
locomotion and is the only part of the body that is in regular contact nerves supply the nail beds. The plantar aspect of the foot is supplied
with the ground (Jones 1949). There are 28 separate bones in the by the medial and lateral plantar nerves, which arise as terminal
human foot, including the sesamoid bones of the first metatarsophalan branches of the tibial nerve. The medial plantar nerve supplies sens
geal joint, and 31 joints, including the ankle joint. The hindfoot com ation to the plantar aspect of the great toe and the second, the third
prises the calcaneus and talus; the midfoot comprises the navicular, and the medial half of the fourth toes. The lateral plantar nerve supplies
cuboid and three cuneiforms; the forefoot comprises five metatarsals, the remaining lateral aspect of the fourth and the entire fifth toe. The
fourteen phalanges and two sesamoid bones. With regard to the nomen heel is innervated by calcaneal branches of the tibial and sural nerves.
clature of the surfaces of the foot, the terms ‘plantar’ and ‘dorsal’ are Injury to any of these nerves can lead to painful neuromas and loss of
used to denote inferior and superior surfaces, respectively. protective sensation. The sural nerve and its branches are especially
prone to neuroma formation.
SKIN AND SOFT TISSUES
SOFT TISSUES
SKIN
Retinacula at the ankle
Vascular supply and lymphatic drainage
In the vicinity of the ankle joint, the tendons of the muscles of the leg
The skin around the ankle is supplied by anterior lateral and anterior are bound down by localized, bandshaped thickenings of the deep
medial malleolar arteries from the anterior tibial artery, posterior fascia termed retinacula, which collectively serve to prevent bowstring
medial malleolar branches from the posterior tibial artery, posterior ing of the underlying tendons during muscle contraction. There are
lateral malleolar branches from the fibular artery, and fasciocutaneous superior and inferior extensor retinacula, superior and inferior fibular
perforators from the anterior and posterior tibial and fibular arteries. retinacula, and a flexor retinaculum.
The main blood supply to the medial side of the heel is from the medial
Extensor retinacula
calcaneal branches of the posterior tibial artery or, sometimes, the
lateral plantar artery passing through the flexor retinaculum. The skin Superior extensor retinaculum
of the lateral side of the heel is supplied by lateral calcaneal branches The superior extensor retinaculum binds down the tendons of tibialis
of the fibular artery and the lateral tarsal artery. The arterial supply to anterior, extensor hallucis longus, extensor digitorum longus and fibu
the skin of the foot is rich and is derived from branches of the dorsalis laris tertius immediately proximal to the anterior aspect of the ankle
pedis (the direct continuation of the anterior tibial artery), posterior joint (see Fig. 83.6; Fig. 84.1). The anterior tibial vessels and deep
tibial and fibular arteries. The skin covering the dorsum of the foot is fibular nerve pass deep to the retinaculum, and the superficial fibular
supplied by the dorsalis pedis artery and by its continuation, the first nerve passes superficially. The retinaculum is attached laterally to the
dorsal metatarsal artery, with smaller contributions from the anterior distal end of the anterior border of the fibula and medially to the ant
perforating branch of the fibular artery and the marginal anastomotic erior border of the tibia. Its proximal border is continuous with the
arteries on the medial and lateral borders of the foot. The skin covering deep fascia of the leg, and dense connective tissue connects its distal
the plantar surface of the foot is supplied by perforating branches of border to the inferior extensor retinaculum. Laterally, it blends with the
the medial and lateral plantar arteries (the terminal branches of the superior fibular retinaculum and medially with the upper border of the
posterior tibial artery). The skin of the forefoot is supplied by cutaneous extensor retinaculum. The tendon of tibialis anterior is the only exten
branches of the common digital arteries. sor tendon that possesses a synovial sheath at the level of the superior
Cutaneous venous drainage is via dorsal and plantar venous arches, extensor retinaculum.
which drain into medial and lateral marginal veins. The medial and
lateral marginal veins form the long and small saphenous veins, respec Inferior extensor retinaculum
tively. On the plantar aspect of the foot, a superficial venous network
The inferior extensor retinaculum is a Yshaped band lying anterior to
forms an intradermal and subdermal mesh that drains to the medial
the ankle joint (see Fig. 83.6; Fig. 84.2). The stem of the Y is at the
and lateral marginal veins. Branches that accompany the medial and
lateral end, where it is attached to the upper surface of the calcaneus,
lateral plantar arteries arise from a deep venous network. Uniquely
anterior to the calcaneal sulcus. The band passes medially, forming a
within the lower limb, venous flow in the foot is bidirectional. However,
strong loop around the tendons of fibularis tertius and extensor digit
when valves are present, flow is from the plantar to the superficial dorsal
orum longus (see Fig. 84.2A). From the deep surface of the loop, a band
system. From here, blood leaves the foot in the superficial and deep
passes laterally behind the interosseous talocalcaneal ligament and the
veins of the lower limb.
cervical ligament, and is attached to the calcaneal sulcus. At the medial
Superficial lymphatic drainage of all areas of the leg and foot
end of the loop, two diverging limbs extend medially to complete the
(except the superficial posterolateral area) is via lymphatic vessels that
‘Y’ shape of the retinaculum. The proximal limb consists of two layers.
accompany the long saphenous vein and its tributaries. The superficial
The deep layer passes deep to the tendons of extensor hallucis longus
posterolateral foot and leg drain into the popliteal lymph nodes via
and tibialis anterior, but superficial to the anterior tibial vessels and
lymphatic vessels that accompany the small saphenous vein. Deep
deep fibular nerve, to reach the medial malleolus. The superficial layer
lymphatic vessels that accompany the dorsalis pedis, posterior tibial
crosses superficial to the tendon of extensor hallucis longus and then
and fibular arteries drain into the popliteal lymph nodes.
adheres firmly to the deep one; in some cases, it continues superficial
to the tendon of tibialis anterior, before blending with the deep layer.
Innervation
The distal limb extends downwards and medially, and blends with the
plantar aponeurosis. It is superficial to the tendons of extensor hallucis
The skin covering the ankle and foot is supplied by nerves derived from longus and tibialis anterior, the dorsalis pedis artery and the terminal
1418 the fourth and fifth lumbar and first sacral spinal nerves (see Figs 78.12, branches of the deep fibular nerve. | 1,940 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Inferior fibular retinaculum
The inferior fibular retinaculum is continuous in front with the infe
Anterior tibial artery rior extensor retinaculum, and is attached posteriorly to the lateral
surface of the calcaneus. Some of its fibres are fused with the perios
teum on the fibular trochlea (peroneal trochlea or tubercle) of the
calcaneus, forming a septum between the tendons of fibularis longus
and brevis.
Superior extensor
Anterior medial retinaculum Synovial sheaths at the ankle
malleolar artery
Anterior to the ankle, the synovial sheath for tibialis anterior extends
Anterior lateral
Synovial sheath surrounding malleolar artery from the proximal margin of the superior extensor retinaculum to the
tibialis anterior
interval between the diverging limbs of the inferior retinaculum (see
Dorsalis pedis Figs 84.1–84.2B). A common sheath encloses the tendons of extensor
artery Inferior extensor digitorum longus and fibularis tertius, starting just above the level of
retinaculum the malleoli, and reaching to the level of the base of the fifth metatarsal
Common (see Figs 84.1, 84.2A). Although variable, the sheath for extensor hal
Medial and lateral
synovial sheath lucis longus begins near that for extensor digitorum longus and extends
tarsal branches
surrounding tendons as far as the base of the first metatarsal (see Figs 84.1–84.2).
of extensor digitorum Posteromedial to the ankle, the sheath for tibialis posterior starts
longus and fibularis tertius
approximately 4 cm above the medial malleolus and ends just proximal
Dorsalis pedis to the attachment of the tendon to the tuberosity of the navicular (see
artery Arcuate artery Fig. 84.2B). The sheath for flexor hallucis longus begins at the level of
the medial malleolus, and extends distally as far as the base of the first
Synovial sheath surrounding
metatarsal (see Fig. 84.2B). Occasionally, as a result of overuse, particu
tendon of extensor
larly in ballet dancers where balance on the tips of the toes en pointe
hallucis longus
involves sustained extreme plantar flexion of the ankle and great toe in
the weightbearing position, a fibrous nodule may develop in the
Tendon of tendon, just proximal to the tendon sheath. This may result in the
First dorsal metatarsal extensor digitorum thickened tendon being caught intermittently in the sheath, causing
artery
longus to second toe pain and ‘triggering’ of the great toe, a condition referred to as hallux
saltans. Surgical opening of the sheath may be required. In athletes, the
muscle belly of flexor hallucis longus may be abnormally large and
First dorsal interosseus
may extend more distally than usual; it can also catch at the opening
of the sheath. The sheath for flexor digitorum longus begins slightly
superior to the level of the medial malleolus and ends at the level of
the navicular.
Posterolateral to the ankle, the tendons of fibularis longus and brevis
are enclosed in a single sheath deep to the superior fibular retinaculum.
This sheath splits into two separate sheaths enclosing their respective
tendons deep to the inferior fibular retinaculum (see Fig. 84.2A). From
the lateral malleolus, it extends for about 4 cm both proximally and
distally.
Plantar aponeurosis
Fig. 84.1 The synovial sheaths of the tendons of the ankle, anterior
aspect. (With permission from Drake RL, Vogl AW, Mitchell A (eds), Gray’s The plantar aponeurosis is composed of densely compacted collagen
Anatomy for Students, 2nd ed, Elsevier, Churchill Livingstone. Copyright fibres orientated mainly longitudinally, but also transversely (Fig.
2010.) 84.3). Its medial and lateral borders overlie the intrinsic muscles of the
great and fifth toes, respectively, while its dense central part overlies the
extrinsic and intrinsic flexors of the digits.
The central part is the strongest and thickest. The fascia is narrow
Flexor retinaculum posteriorly, where it is attached to the medial process of the calcaneal
The flexor retinaculum is attached anteriorly to the medial malleolus, tuberosity proximal to flexor digitorum brevis, and traced distally it
distal to which it is continuous with the deep fascia on the dorsum of becomes broader and somewhat thinner. Just proximal to the level of
the foot (see Fig. 84.2B). From its malleolar attachment, it extends the metatarsal heads, it divides into five bands, one for each toe. As
posteroinferiorly to the medial process of the calcaneus and the plantar these five digital bands diverge below the metatarsal shafts, they are
aponeurosis. Proximally, there is no clear demarcation between its united by transverse fibres. Proximal, plantar and a little distal to the
border and the deep fascia of the leg, especially the deep transverse layer metatarsal heads and the metatarsophalangeal joints, the superficial
of the deep fascia. Distally, its border is continuous with the plantar stratum of each of the five bands is connected to the dermis by skin
aponeurosis, and many fibres of abductor hallucis are attached to it. ligaments (retinacula cutis). These ligaments reach the skin of the first
The flexor retinaculum converts grooves on the tibia and calcaneus into metatarsophalangeal joint proximal to, and in the floors of, the furrows
canals for the tendons, and bridges over the posterior tibial vessels and that separate the toes from the sole; Ledderhose’s disease (plantar
tibial nerve. As these structures enter the sole, they are, from medial to fibromatosis) may involve these ligaments, resulting in contractures of
lateral, the tendons of tibialis posterior and flexor digitorum longus, the affected digits. The deep stratum of each digital band of the aponeu
the posterior tibial vessels, the tibial nerve and the tendon of flexor rosis yields two septa that flank the digital flexor tendons and separate
hallucis longus (see Fig. 84.14). them from the lumbricals and the digital vessels and nerves. These septa
pass deeply to fuse with the interosseous fascia, the deep transverse
Fibular retinacula metatarsal ligaments (which run between the heads of adjacent meta
The fibular retinacula are fibrous bands that retain the tendons of fibu tarsals), the plantar ligaments of the metatarsophalangeal joints, and
laris longus and brevis in position as these tendons cross the lateral the periosteum and fibrous flexor sheaths at the base of each proximal
aspect of the ankle region (see Fig. 84.2A). phalanx. Pads of fat develop in the web spaces between the metatarsal
heads and the bases of the proximal phalanges; they cushion the digital
Superior fibular retinaculum nerves and vessels from adjoining tendinous structures and extraneous
The superior fibular retinaculum is a short band that extends from the plantar pressures. Just distal to the metatarsal heads, a plantar interdig
back of the lateral malleolus to the deep transverse fascia of the leg and ital ligament (superficial transverse metatarsal ligament) blends pro
the lateral surface of the calcaneus. Damage to the retinaculum can lead gressively with the deep aspect of the superficial stratum of the plantar
to instability of the tendons of fibularis longus and brevis. aponeurosis where it enters the toes (see Fig. 84.3). The central part of | 1,941 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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noITCES
A
Tendon of extensor hallucis longus
Extensor digitorum longus
Fibularis brevis
Synovial sheath surrounding tendons of
extensor digitorum longus and fibularis tertius Fibula
Synovial sheath of extensor hallucis longus tendon
Fibularis longus
Extensor hallucis brevis Inferior extensor retinaculum
Calcaneal tendon
Tendons of extensor digitorum longus
Superior fibular retinaculum
Inferior fibular retinaculum
Extensor digitorum brevis
Tendon of fibularis tertius
Common synovial sheath for tendons
Tendon of fibularis brevis of fibularis longus and fibularis brevis
B
Synovial sheath of
tibialis posterior
tendon
Synovial sheath of flexor
digitorum longus tendon Synovial sheath of tibialis anterior tendon
Synovial sheath of
flexor hallucis longus
Inferior extensor retinaculum
tendon
Calcaneal tendon Synovial sheath of extensor hallucis longus tendon
Flexor retinaculum Synovial sheath of flexor hallucis longus tendon
Synovial sheath of
tibialis posterior
tendon
Tendon of abductor hallucis
Abductor hallucis
Synovial sheaths of
Flexor digitorum brevis tendons in toes
Synovial sheath of flexor digitorum longus tendon
Fig. 84.2 The synovial sheaths of the tendons of the ankle. A, Lateral aspect. B, Medial aspect. (With permission from Waschke J, Paulsen F (eds),
Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
the plantar aponeurosis thus provides an intermediary structure between an intermuscular septum, and dorsally by the first metatarsal. The
the skin and the osteoligamentous framework of the foot via numerous central compartment contains flexor digitorum brevis, the lumbricals,
cutaneous retinacula and deep septa that extend to the metatarsals and flexor accessorius (quadratus plantae), adductor hallucis, and the
phalanges. The central part is also continuous with the medial and tendons of flexor digitorum longus. The central compartment is
lateral parts; at the junctions, two intermuscular septa, medial and bounded by the plantar aponeurosis inferiorly, the osseofascial tar
lateral, extend in oblique vertical planes between the medial, intermedi sometatarsal structures dorsally and intermuscular septa medially and
ate and lateral groups of plantar muscles to reach bone. Thinner, hori laterally. The lateral compartment contains abductor digiti minimi and
zontal intermuscular septa, derived from the vertical intermuscular flexor digiti minimi brevis, and its boundaries are the fifth metatarsal
septa, pass between the muscle layers. dorsally, the plantar aponeurosis inferiorly and laterally, and an inter
The lateral part of the plantar aponeurosis, which covers abductor muscular septum medially. The interosseous compartment contains the
digiti minimi, is thin distally and thick proximally, where it forms a seven interossei and its boundaries are the interosseous fascia and the
strong band, sometimes containing muscle fibres, between the lateral metatarsals.
process of the calcaneal tuberosity and the base of the fifth metatarsal. The dorsal aspect of the foot effectively contains a single compart
It is continuous medially with the central part of the aponeurosis, and ment, which is occupied by the extrinsic extensor tendons and exten
with the fascia on the dorsum of the foot around its lateral border. The sor digitorum brevis, and is roofed by the deep dorsal fascia (see
medial part of the plantar aponeurosis, which covers abductor hallucis, below).
is thin. It is continuous proximally with the flexor retinaculum, medi
ally with the dorsal fascia of the foot, and laterally with the central part Lateral intermuscular septum
of the plantar aponeurosis. The lateral intermuscular septum is incomplete, especially at its proxi
mal end where the lateral plantar artery and nerve enter the lateral
Plantar fasciitis
compartment. Distally, its deep attachments are to the fibrous sheath
Plantar fasciitis is a common cause of plantar heel pain. of fibularis longus and to the fifth metatarsal.
Fascial compartments of the foot Medial intermuscular septum
The medial intermuscular septum is incomplete where the tendon of
There are four main compartments of the plantar aspect of the foot (Fig. flexor digitorum longus enters the central compartment and where
84.4). The medial compartment contains abductor hallucis and flexor adductor hallucis and the lateral head of flexor hallucis brevis enter the
hallucis brevis, as well as the tendon of flexor hallucis longus. The medial compartment. The septum divides into three bands – proximal,
medial compartment is bounded inferiorly and medially by the medial intermediate and distal, each of which displays lateral and medial divi
part of the plantar aponeurosis and its medial extension, laterally by sions as it approaches its deep attachments. The proximal band is | 1,942 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
48
RETPAHC
Ankle and foot
Many contributing aetiological factors have been reported, such as
obesity, abnormal posture, advanced age, and extrinsic factors such as
poor footwear and excessive biomechanical stressors (League 2008).
These factors may lead to inflammation and degeneration of the plantar
aponeurosis. However, recent histological studies have called into ques
tion the role of inflammation in the aetiology of the disease and have
led to the recommendation that the term ‘fasciitis’ be replaced with
‘fasciosis’ (Lemont et al 2003). The stress and strain applied to the
plantar aponeurosis may lead to the formation of a bony spur at its
proximal attachment to the calcaneus. Clinically, palpation of the
plantar aponeurosis at the medial tubercle of the calcaneus may result
in localized tenderness and exacerbated heel pain in patients. Multiple
treatments, from conservative therapies to surgical interventions, have
been used to provide pain relief. Nonoperative treatments include
stretching exercises, orthoses, extracorporeal shockwave therapy, mult
iple steroid injections, padding and strapping (Landorf and Menz
2008). Recently, the use of cryosurgery has been investigated for this
condition (Cavazos et al 2009). Surgical treatments include partial or
complete release of the plantar aponeurosis with concomitant heel spur
resection and nerve decompression, when necessary (League 2008).
1420.e1 | 1,943 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Bones
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48
RETPAHC
attached laterally to the cuboid and blends medially with the tendon to relieve the increased pressure in the compartment surgically results
of tibialis posterior. The middle band is attached laterally to the cuboid in necrosis of the soft tissues within the compartment. The most
and the long plantar ligament, and medially to the medial cuneiform. common cause of compartment syndrome in the foot is trauma, usually
The distal band divides to enclose the tendon of flexor hallucis longus of highenergy (highimpact) type; crush injuries, calcaneal fractures
and is attached to the fascia over flexor hallucis brevis. and disruption of the tarsometatarsal joints are the usual antecedents
associated with compartment syndrome in the foot.
Deep dorsal fascia
The deep fascia on the dorsum of the foot (fascia dorsalis pedis) is a Specialized adipose tissue (heel and
thin layer, continuous above with the inferior extensor retinaculum; it
metatarsal pads)
covers the dorsal extensor tendons and extensor digitorum brevis.
Compartment syndrome in the foot
The heel is subject to repeated high impacts and is anatomically adapted
A compartment syndrome results from an increase in intracompart to withstand these pressures. The adult heel pad has an average thick
mental pressure sufficient to impair venous outflow from that compart ness of 18 mm and a mean epidermal thickness of 0.64 mm (dorsal
ment. As blood enters at arterial pressure, the compartment pressure epidermal thickness averages 0.069 mm). The heel pad contains elastic
increases further until it exceeds arterial pressure, at which point inflow adipose tissue organized as spiral fibrous septa anchored to each other,
of arterial blood ceases, leading to muscle and nerve ischaemia. Failure to the calcaneus and to the skin. The septa are Ushaped, fatfilled
columns designed to resist compressive loads and are reinforced intern
ally with elastic diagonal and transverse fibres, which separate the fat
into compartments.
In the forefoot, the subcutaneous tissue consists of fibrous lamellae
arranged in a complex whorl containing adipose tissue attached via
vertical fibres to the dermis superficially and the plantar aponeurosis
deeply. The fat is particularly thick in the region of the metatarsophalan
geal joints, which cushions the foot during the toeoff phase of gait (see
below). Like the heel pad, the metatarsal fat pad is designed to with
Superficial stand compressive and shearing forces. Atrophy of either may be a cause
transverse of persistent pain in the distal plantar region.
metatarsal
ligament
BONES
Transverse
fascicles
Functionally, the skeleton of the foot may be divided into the tarsus,
metatarsus and phalanges. Anatomically, it may be divided into the
hindfoot (calcaneus and talus), midfoot (navicular, cuboid and cunei
forms), and forefoot (metatarsals, phalanges, and sesamoid bones of
the great toe).
DISTAL TIBIA
The distal end of the tibia has anterior, medial, posterior, lateral and
distal surfaces, and projects inferomedially as the medial malleolus (see
Figs 83.3–83.4). The distal surface, also called the tibial plafond, articu
lates with the talus and is wider anteriorly than posteriorly. It is concave
Medial sagittally and slightly convex transversely, and continues medially into
malleolus Plantar
the malleolar articular surface. The medial malleolus is short and thick,
aponeurosis
Abductor and has a smooth lateral surface with a crescentic or commashaped
hallucis Lateral facet that articulates with the medial surface of the talar body. The
malleolus
distal end of the tibia, including its ossification, is described in detail
on page 1404.
Ligamentous attachments No muscles are attached to the distal
Subcutaneous
calcaneal bursa tibia. The interosseous membrane, the deltoid ligament, and the ante
rior and posterior tibiofibular ligaments are attached to the distal tibia.
Fig. 84.3 The plantar aponeurosis. (With permission from Waschke J, Vascular supply The distal tibia is supplied by an arterial network
Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, formed by branches of the dorsalis pedis, posterior tibial and fibular
Urban & Fischer. Copyright 2013.) arteries.
Fig. 84.4 A coronal section through the
Tendons of extensor hallucis Tendons of extensor digitorum longus
longus and extensor and extensor digitorum brevis midfoot showing the main fascial
hallucis brevis compartments.
Dorsal fascia
First, second, third and fourth
Adductor hallucis,
dorsal interossei
oblique head
Abductor hallucis Opponens digiti minimi
Tendon of flexor First, second and third
hallucis longus plantar interossei
Abductor digiti minimi
Flexor hallucis brevis
Flexor digiti minimi brevis
Tendons of flexor digitorum
longus and flexor digitorum brevis Plantar aponeurosis | 1,944 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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noITCES
Innervation The distal tibia is innervated by branches from the deep Vascular supply The distal fibula is supplied by an arterial network
fibular, tibial, saphenous and sural nerves. made up of branches of the dorsalis pedis, posterior tibial and fibular
arteries.
DISTAL FIBULA Innervation The distal fibula is innervated by the deep fibular, tibial,
saphenous and sural nerves.
The distal end of the fibula or lateral malleolus projects distally and
posteriorly relative to the medial malleolus (see Figs 83.3–83.4). Its
lateral aspect is subcutaneous, the posterior surface has a broad groove TARSUS
with a prominent lateral border, and the anterior surface is rough and
somewhat rounded and articulates with the anteroinferior aspect of the The seven tarsal bones occupy the proximal half of the foot (Figs
tibia. The medial surface has a triangular articular facet and is vertically 84.5–84.6). The tarsus and carpus are homologous, but the tarsal ele
convex with its apex directed distally. It articulates with the lateral talar ments are larger, reflecting their role in supporting and distributing
surface. Behind the facet is a rough malleolar fossa for ligamentous body weight. As in the carpus, tarsal bones are arranged in proximal
attachment. The distal end of the fibula, including its ossification, is and distal rows, but medially, there is an additional single intermediate
described in detail on page 1406. tarsal element, the navicular. The proximal row is made up of the talus
and calcaneus; the long axis of the talus is inclined anteromedially and
Ligamentous attachments No muscles are attached to the distal inferiorly, and its distally directed head is medial to the calcaneus and
fibula below the level of the interosseous ligament. The ligamentous at a superior level. The distal row contains, from medial to lateral, the
attachments are those of the lateral ligament complex, i.e. the anterior medial, intermediate and lateral cuneiforms and the cuboid. Collec
talofibular, the calcaneofibular and the posterior talofibular ligaments. tively, these bones display an arched transverse alignment that is dor
The interosseous membrane is attached on its medial aspect. sally convex. Medially, the navicular is interposed between the head of
A B
Extensor digitorum
Flexor hallucis
longus and extensor
digitorum brevis longus Flexor digitorum
longus
Extensor hallucis
longus
Dorsal interossei
Extensor Adductor hallucis
digitorum longus Extensor hallucis and flexor hallucis
brevis brevis
Abductor hallucis
Dorsal Flexor digitorum
Abductor hallucis
interossei brevis
Abductor Plantar interossei Flexor hallucis Abductor digiti
digiti minimi brevis minimi
Plantar interossei
First to
fourth dorsal
First
Second First to interossei
Dorsal
Third interossei third plantar
interossei
Fourth Opponens digiti
Fibularis longus minimi
Medial cuneiform Tibialis anterior A obd ld iqu uc eto hr eh aa dllucis,
Fibularis
Intermediate
tertius
cuneiform Flexor digiti
Lateral cuneiform minimi brevis
Fibularis
brevis Abductor digiti
Tibialis posterior minimi
Navicular
Cuboid Fibularis brevis
Tuberosity of
Flexor hallucis
navicular
brevis
Extensor digitorum Head of talus
Short plantar
brevis Plantar calcaneo-
Neck of talus ligament
navicular ligament
Extensor
Facet for medial digitorum
malleolus brevis
Long plantar
Trochlear surface
Flexor accessorius ligament
Abductor hallucis
Posterior tubercle Abductor digiti
of talus Flexor digitorum minimi
Calcaneus brevis
Calcaneal tendon Plantaris Calcaneal tendon
Attachments from ligamentous and tendinous extensions in the sole of the foot (not direct from bone)
Fig. 84.5 The skeleton of the left foot, with muscle attachments. A, Dorsal aspect. B, Plantar aspect. The attachments of tibialis posterior to the
metatarsals vary; those to the third and fifth metatarsals are sometimes absent. | 1,945 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Bones
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RETPAHC
1 2 3 4 5 6 7 Appears 9th to 12th week
Appears 6th year
Unites by 18th year
Appears after 15th week
Unites by 18th year
Appears 3rd to 6th year
Appears 11th to 15th week
Unites 18th year
Appears 2nd to 8th year
8 Appears 3rd to 4th year
Unites 17th to 20th year
9
10
Appears 9th week
11
Appears 10th week
A
12 13 14 15 16 17 18 19
Unites 17th to 20th year
Intermediate cuneiform,
9 3rd year Appears 3rd year
10 Lateral cuneiform, Medial cuneiform, 2nd year
1st year
11
12 Cuboid, 9th (fetal) month Navicular, 3rd year
13
1
14
2 15
Talus, 6th (fetal) month
16
17
3
18
Calcaneus, 3rd to 4th (fetal) month
Epiphysis for posterior part
4
of calcaneus appears
6th to 8th year; unites
19 14th to 16th year
5
20 Fig. 84.7 Ossification of the bones of the foot.
6
21
ends of the longitudinal arches. For the purposes of description, each
7
tarsal bone is arbitrarily considered to be cuboidal in form, with six
22
surfaces. The ossification sites and timing of ossification are summa
rized in Figure 84.7.
8
23
Talus
The talus is an intercalated bone with no tendinous attachments. It is
the osseous link between the foot and leg through the ankle joint (see
Figs 84.16 and 84.18).
B
Head Directed distally and somewhat inferomedially, the head has a
distal surface, which is ovoid and convex; its long axis is also inclined
Fig. 84.6 A, A lateral radiograph of the adult ankle and foot in full
inferomedially to articulate with the proximal navicular surface (see Fig.
plantigrade contact with the ground, during symmetrical standing, in a
man aged 24 years. Key: 1, fibula; 2, tibia; 3, talar neck; 4, talar head; 5, 84.5A). The plantar surface of the head has three articular areas, sepa
talonavicular joint; 6, navicular; 7, medial cuneiform; 8, talocrural joint; 9, rated by smooth ridges (Fig. 84.8C). The most posterior and largest is
talar body; 10, posterior process of talus; 11, subtalar joint; 12, calcaneus oval and slightly convex, and rests on a shelflike medial calcaneal
(note the trabecular pattern); 13, tarsal sinus; 14, calcaneocuboid joint; projection, the sustentaculum tali. Anterolateral to this and usually
15, cuboid; 16, styloid process of the fifth metatarsal; 17, base of the first continuous with it, a flat articular facet rests on the anteromedial part
metatarsal; 18, shaft of the first metatarsal; 19, head of the first of the dorsal (proximal) calcaneal surface; distally, it continues into the
metatarsal. B, A dorsoplantar radiograph of adult foot in full plantigrade navicular surface. Between the two calcaneal facets, a part of the talar
contact with the ground, during symmetrical standing, in a man aged 24 head, covered with articular cartilage, is in contact with the plantar
years. Key: 1, interphalangeal joint; 2, middle phalanx; 3, head of fifth calcaneonavicular (spring) ligament, which is covered here, superiorly,
metatarsal; 4, shaft of fifth metatarsal; 5, base of fifth metatarsal; 6, lateral by fibrocartilage (see Fig. 84.13B). When the foot is inverted passively,
cuneiform; 7, cuboid; 8, calcaneus; 9, head of distal phalanx; 10, shaft of the dorsolateral aspect of the head is visible and palpable approxi
distal phalanx; 11, base of distal phalanx; 12, head of proximal phalanx; mately 3 cm distal to the tibia; it is hidden by extensor tendons when
13, shaft of proximal phalanx; 14, base of proximal phalanx; 15, first
the toes are dorsiflexed.
metatarsophalangeal joint; 16, lateral (fibular) sesamoid; 17, medial (tibial)
sesamoid; 18, shaft of first metatarsal; 19, first metatarsocuneiform joint; Neck The neck is the narrow, medially inclined region between the
20, medial cuneiform; 21, intermediate cuneiform; 22, tuberosity of
head and body. Its rough surfaces are for ligaments. The medial plantar
navicular; 23, talar head. (Courtesy of New York College of Podiatric
surface has a deep sulcus tali that, when the talus and calcaneus are
Medicine, New York, NY.)
articulated, forms a roof to the tarsal sinus, which is occupied by inter
osseous talocalcaneal and cervical ligaments.
the talus and the cuneiforms. Laterally, the calcaneus articulates with The long axis of the neck, inclined downwards, distally and medially,
the cuboid. makes an angle of approximately 150° with that of the body; it is
The tarsus and metatarsus are arranged to form intersecting longitu smaller (130–140°) at birth, accounting in part for the inverted foot in
dinal and transverse arches. Hence, thrust and weight are not transmit young children. The dorsal talonavicular ligament and ankle articular
ted from the tibia to the ground (or vice versa) directly through the capsule are attached distally to the dorsal surface of the talus. Thus, the
tarsus, but are distributed through the tarsals and metatarsals to the proximal part of this surface lies within the capsule of the ankle joint. | 1,946 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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In a hypermobile flat foot undergoing pronation, the talar head is
unsupported medially by the sustentaculum tali. The resulting lack of
support results in a visible medial protrusion of the talar head as the
foot adducts and plantar flexes towards the ground (Michaud 2011).
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The medial articular facet of the talar body and part of the trochlear The middle third of the talar body, other than its most superior aspect,
surface may extend on to the neck. The anterior talofibular ligament is and the lateral third, other than its posterior aspect, are supplied mainly
attached on the lateral aspect of the neck, spreading along the adjacent by the anastomotic arcade in the tarsal canal. The medial third of the
anterior border of the lateral surface. The interosseous talocalcaneal and body of the talus is supplied by the branch of the artery of the tarsal
cervical ligaments are attached to the inferior surface of the neck. A canal to the deltoid ligament.
dorsolateral, socalled ‘squatting facet’ is commonly present on the talar
neck in those individuals who habitually adopt the squatting position; Innervation The talus is innervated by branches from the deep fibular,
it articulates with the anterior tibial margin in extreme dorsiflexion and tibial, saphenous and sural nerves.
may be doubled.
Ossification A single ossification centre appears prenatally at 6
Body The body is cuboidal, covered dorsally by a trochlear surface months (see Fig. 84.7). The posterolateral process sometimes fuses with
articulating with the distal end of the tibia. It is anteroposteriorly an accessory bone called the os trigonum.
convex, gently concave transversely, widest anteriorly and, therefore,
sellar in shape. The triangular lateral surface is smooth and vertically Talar fractures Since 70% of the surface of the talus is covered by
concave for articulation with the lateral malleolus. Superiorly, it is articular cartilage, displaced talar neck fractures, where the blood supply
continuous with the trochlear surface; inferiorly, its apex is a lateral to the talar body is interrupted, may result in avascular necrosis and
process. Proximally, the medial surface is (posterosuperiorly) covered nonunion. Transchondral fractures of the superior aspect of the talus
by a commashaped facet, which is deeper in front and articulates with are frequently overlooked on initial radiographs of patients with ankle
the medial malleolus. Distally, this surface is rough and contains complaints (Trepal et al 1986). A systematic review by Halvorson et al
numerous vascular foramina. The small posterior surface features a (2012) reported that approximately 33% of talar neck fractures progress
rough projection termed the posterior process. The process is marked to avascular necrosis, 20% progress to malunions and 5% progress to
by an oblique groove between two tubercles. The lateral tubercle is nonunions. In general, these complications do not occur in non
usually larger; the medial is less prominent and lies immediately behind displaced fractures. If a subchondral lucency is seen in the talus on
the sustentaculum tali. The plantar surface articulates with the middle radiographs at 8 weeks after fracture of the talar neck (Hawkins sign),
third of the dorsal calcaneal surface by an oval concave facet, its long it may be assumed that vascularity to the talar body is intact and that
axis directed distolaterally at an angle of approximately 45° with the the fracture is likely to heal satisfactorily.
median plane. The medial edge of the trochlear surface is straight, but
Calcaneus
its lateral edge inclines medially in its posterior part and is often broad
ened into a small, elongated triangular area, which is in contact with The calcaneus is the largest of the tarsal bones and projects posterior
the posterior tibiofibular ligament in dorsiflexion. to the tibia and fibula as a short lever for muscles of the calf attached
The posterior talofibular ligament is attached to the lateral tubercle to its posterior surface. It is irregularly cuboidal, its long axis being
of the posterior process (posterolateral tubercle). Its attachment extends inclined distally upwards and laterally (see Fig. 84.8A,B). It has a rela
up to the groove, or depression, between the process and posterior tively thin cortex (Daftary et al 2005). The superior or proximal surface
trochlear border. The posterior talocalcaneal ligament is attached to the is divisible into three areas. The posterior third is rough and concavo
plantar border of the posterior process. The groove between the tuber convex; the convexity is transverse and supports fibroadipose tissue
cles of the process contains the tendon of flexor hallucis longus and (Kager’s fat pad) between the calcaneal tendon and ankle joint. The
continues distally into the groove on the plantar aspect of the susten middle third carries the posterior talar facet, which is oval and convex
taculum tali. The medial talocalcaneal ligament is attached below to anteroposteriorly. The anterior third is partly articular; distal (anterior)
the medial tubercle, whereas the most posterior superficial fibres of to the posterior articular facet, a rough depression, the calcaneal sulcus,
the deltoid ligament are attached above the tubercle. The deep fibres narrows into a groove on the medial side and completes the tarsal sinus
of the deltoid ligament are attached more superiorly to the rough area with the talus (see Fig. 84.8B). (The tarsal sinus is a conical hollow
immediately below the commashaped articular facet on the medial bounded by the talus medially, superiorly and laterally, with the supe
surface. rior surface of the calcaneus below. Its medial end is narrow and tunnel
shaped, and is often referred to as the tarsal canal.) Distal and medial
Ligamentous attachments No muscles are attached to the talus. to this groove, an elongated articular area covers the sustentaculum tali
However, many ligaments are attached to the bone, and these confer (talar shelf) and extends distolaterally on the body of the bone. This
stability to the talocrural, subtalar and talocalcaneonavicular joints. facet is often divided into middle and anterior talar facets by a non
articular interval at the anterior limit of the sustentaculum tali (the
Vascular supply The talar blood supply is rather tenuous because incidence of this subdivision varies with sex, race and occupation).
of the lack of muscle attachments. The first comprehensive account of Rarely, all three facets on the upper surface of the calcaneus are fused
talar blood supply was provided by Wildenauer in 1950. The extraos into one irregular area.
seous blood supply is via the posterior tibial, dorsalis pedis and fibular The anterior surface is the smallest, and is an obliquely set concavo
arteries (Fig. 84.9). The ‘artery of the tarsal canal’ arises from the pos convex articular facet for the cuboid. The posterior surface is divided
terior tibial artery approximately 1 cm proximal to the origin of the into three regions: a smooth proximal (superior) area separated from
medial and lateral plantar arteries (Fig. 84.10) and passes anteriorly the calcaneal tendon by a bursa and adipose tissue; a middle area,
between the sheaths of flexor digitorum longus and flexor hallucis which is the largest, limited above by a groove and below by a rough
longus to enter the tarsal canal, in which it lies anteriorly, close to the ridge for the calcaneal tendon; and a distal (inferior) area, vertically
talus. (The ‘tarsal canal’ is the term that is commonly used to describe striated and inclined downwards and forwards, which is the subcutan
the tunnelshaped medial end of the tarsal sinus.) Branches from the eous weightbearing surface.
arterial network in the tarsal canal enter the talus. The artery continues The plantar surface is rough, especially proximally as the calcaneal
through the tarsal canal into the lateral part of the tarsal sinus, where tuberosity, the lateral and medial processes of which extend distally,
it anastomoses with the artery of the tarsal sinus, forming a vascular separated by a notch. The medial process is longer and broader (see Fig.
sling under the talar neck. A branch of the artery of the tarsal canal 84.8B). Further distally, an anterior tubercle marks the distal limit of
known as the deltoid branch passes deep to the deltoid ligament and the attachment of the long plantar ligament.
supplies part of the medial aspect of the talar body. Sometimes, it arises The lateral surface is almost flat. It is proximally deeper and palpable
from the posterior tibial artery; rarely, it arises from the medial plantar on the lateral aspect of the heel distal to the lateral malleolus. Distally,
artery; it may be the only remaining arterial supply to the talus when it presents the fibular trochlea (see Fig. 84.8A,B), which is exceedingly
this bone is fractured. The dorsalis pedis artery supplies branches to the variable in size and palpable 2 cm distal to the lateral malleolus when
superior aspect of the talar neck and also gives off the artery of the tarsal well developed. It bears an oblique groove for the tendon of fibularis
sinus. This large vessel is always present and anastomoses with the longus and a shallower proximal groove for the tendon of fibularis
artery of the tarsal canal. The artery of the tarsal sinus receives a contri brevis. About 1 cm or more behind and above the fibular trochlea, a
bution from the anterior perforating branch of the fibular artery and second elevation may exist for attachment of the calcaneofibular part
supplies direct branches to the talus. The fibular artery provides small of the lateral ligament.
branches, which form a plexus of vessels posteriorly with branches of The medial surface is vertically concave, and its concavity is accentu
the posterior tibial artery; however, the contribution that the fibular ated by the sustentaculum tali, which projects medially from the distal
artery makes to the talar blood supply is thought to be insignificant. part of its upper border (see Fig. 84.8B). Superiorly, the process bears
The intraosseous blood supply of the talar head arises medially from the middle talar facets and inferiorly a groove, which is continuous with
branches of the dorsalis pedis and laterally via vessels that arise from that on the talar posterior surface for the tendon of flexor hallucis
the anastomosis between the arteries of the tarsal canal and tarsal sinus. longus (see Fig. 84.8A,B). The medial aspect of the sustentaculum tali | 1,948 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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This accessory bone is occasionally found and arises from a separate
ossification centre that appears between 8 and 11 years of age. When
the os trigonum fuses to the posterolateral process of the talus it is
called the trigonal process (Stieda’s process). Another accessory bone
(although rare) of the foot is the os supratalare, which lies on the dorsal
aspect of the talus; it rarely measures more than 4 mm in length.
A detailed analysis of patterns of anterior talar articular facets in a
series of 401 Indian calcanei revealed four types. Type I (67%) showed
one continuous facet on the sustentaculum extending to the disto
medial calcaneal corner; type II (26%) presented two facets, one sus
tentacular and one distal calcaneal; type III (5%) possessed only a single
sustentacular facet; and type IV (2%) showed confluent anterior and
posterior facets (Gupta et al 1977).
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A Foot bones Talus
Medial aspect Navicular
Intermediate cuneiform
Medial cuneiform
Calcaneus
Metatarsals
Proximal
phalanges
Middle
phalanges
Groove for tendon of Distal
flexor hallucis longus phalanges
Talus
Lateral aspect Navicular
Intermediate cuneiform
Lateral cuneiform
Calcaneus
Metatarsals
Phalanges
Fibular trochlea
Cuboid
B Calcaneus For cuboid
Anterior articular
surface for talus
Anterior tubercle
Middle articular
Sustentaculum tali
surface for talus
Groove for tendon Fibular trochlea
of flexor hallucis Calcaneal sulcus
longus
Posterior articular
surface for talus
Medial process
Lateral process
Calcaneal tuberosity
Inferior aspect Superior aspect
Sustentaculum tali Calcaneal sulcus
Posterior articular
surface for talus Middle articular Posterior articular
surface for talus surface for talus
Anterior articular
For calcaneofibular
surface for talus
ligament
Posterior surface
Fibular trochlea
Lateral process of
Anterior tubercle calcaneal tuberosity
Medial aspect Lateral aspect
For navicular
C Talus For anterior
calcaneal surface
For calcaneonavicular
ligament For medial malleolus
For lateral malleolus
For distal end
Sulcus tali of tibia
Posterior
calcaneal surface
Inferior aspect Superior aspect
For distal end of tibia
Neck
For lateral malleolus
For medial malleolus
Head
For navicular Posterior calcaneal
surface
Medial aspect Lateral aspect
Fig. 84.8 The skeleton of the foot. A, Foot bones. B, Calcaneus. C, Talus. (With permission from Drake RL, Vogl AW, Mitchell A, et al (eds), Gray’s Atlas
of Anatomy, Elsevier, Churchill Livingstone. Copyright 2008.) | 1,950 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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noITCES
to the tubercle and the area distal to it. The lateral tendinous head of
Fibular artery Posterior tibial
artery flexor accessorius is attached distal to the lateral process near the lateral
Anterior tibial artery margin of the long plantar ligament. Plantaris is attached to the poste
Perforating branch
rior surface near the medial side of the calcaneal tendon. The anterior
Anterior medial malleolar artery of fibular artery part of the lateral surface is crossed by the fibular tendons but is largely
subcutaneous. The calcaneofibular ligament is attached 1–2 cm proxi
Anterior lateral malleolar artery Communicating
mal to the fibular trochlea, usually to a low, rounded elevation.
branch
Lateral tarsal artery The dorsal surface of the sustentaculum tali is part of the talocalca
Dorsalis pedis artery neonavicular joint; its plantar surface is grooved by the tendon of flexor
Posterior medial hallucis longus, and margins of the groove give attachment to the deep
malleolar branch
of posterior tibial part of the flexor retinaculum. The plantar calcaneonavicular ligament
artery is attached distally to the medial margin of the sustentaculum, which
is narrow, rough and convex. A slip from the tendon of tibialis posterior,
Medial plantar
artery and superficial fibres of the deltoid ligament and medial talocalcaneal
ligaments are attached proximally. Distal to the attachment of the
Lateral plantar deltoid ligament, the tendon of flexor digitorum longus is related to
artery the margin of the sustentaculum tali and may groove it. The large
medial head of flexor accessorius is attached distal to the groove for
flexor hallucis longus.
Vascular supply The calcaneus receives its arterial supply from the
medial and lateral calcaneal arteries (arising from the posterior tibial
and fibular arteries, respectively), fibular artery, posterior calcaneal
Arcuate artery anastomosis (formed from the posterior tibial and fibular arteries),
medial and lateral plantar arteries, artery of the tarsal sinus and tarsal
Calcaneal branches of canal, branches of the lateral tarsal artery and perforating fibular
fibular artery arteries.
Calcaneal branches of posterior
tibial and lateral plantar arteries
Innervation The calcaneus is innervated by branches of the tibial,
Fig. 84.9 The arterial anastomoses of the ankle, tarsus and metatarsus. sural and deep fibular nerves.
Ossification The calcaneus is the only tarsal bone that always has
two ossification centres (see Fig. 84.7). In addition to the main ossifica
tion centre, there is a scalelike posterior apophysis that covers most of
the posterior, and part of the plantar, surfaces. The main centre appears
prenatally in the third month, whereas the posterior apophysis appears
in the sixth year in females and the eighth year in males, fusing in the
Calcaneal tendon fourteenth and sixteenth years, respectively.
Tendon of tibialis posterior
An os calcaneus secundarius, an accessory bone rather than a sec
ondary ossification centre, occasionally occurs. When present, it is
located on the socalled anterior process of the calcaneus, from which
Posterior tibial artery Tendon of flexor digitorum longus
the bifurcate ligament arises, in an interval between the anteromedial
aspect of the calcaneus, the proximal ends of the cuboid and navicular,
Artery of the tarsal canal and the head of the talus. Other rare accessory bones of the calcaneus
Tendon of flexor include the calcaneus accessorius in the region of the fibular trochlea;
hallucis longus the os sustentaculi on the posterior aspect of the sustentaculum tali; the
os subcalcis on the plantar aspect of the calcaneus slightly posterior to
the origin of the plantar aponeurosis; and the os aponeurosis plantaris,
which lies within the plantar aponeurosis in close proximity to the
Calcaneal
branches medial process of the calcaneal tuberosity.
Navicular
The navicular articulates with the talar head proximally and with the
cuneiform bones distally (see Fig. 84.8A; Fig. 84.11). In convex pes
planovalgus (vertical talus), the navicular is subluxed dorsally and
Fig. 84.10 Branches of the posterior tibial artery, posteromedial view of
the ankle. articulates instead with the talar neck. The downward displacement of
the talar head creates a characteristic convex ‘rockerbottom foot’. The
distal surface of the navicular is transversely convex and divided into
three facets (the medial being the largest) for articulation with the
can be felt immediately distal to the tip of the medial malleolus; occa cuneiforms. The proximal surface is oval and concave, and articulates
sionally, it is also grooved by the tendon of flexor digitorum longus. with the talar head. The dorsal surface is rough and convex. The medial
surface is also rough and projects proximally as a prominent tuberosity,
Muscle and ligamentous attachments The interosseous talo palpable approximately 2.5 cm distal and plantar to the medial malleo
calcaneal and cervical ligaments and the medial root of the inferior lus. The plantar surface, rough and concave, is separated from the
extensor retinaculum are attached in the calcaneal sulcus. The non tuberosity medially by a groove for the tendon of tibialis posterior. The
articular area distal to the posterior talar facet is the site of attachment lateral surface is rough and irregular, and often bears a facet for articula
of extensor digitorum brevis (in part), the principal band of the inferior tion with the cuboid.
extensor retinaculum and the stem of the bifurcate ligament. The facet for articulation with the medial cuneiform is roughly tri
Abductor hallucis and the superficial part of the flexor retinaculum angular, its rounded apex is medial and its ‘base’, facing laterally, is
and, distally, the plantar aponeurosis and flexor digitorum brevis are often markedly curved; the articular facets for the intermediate and
all attached to the medial process (medial condyle) of the calcaneal lateral cuneiforms are also triangular, with plantarfacing apices. The
tuberosity at its prominent medial margin. The medial process of the facet for the lateral cuneiform may appear as a wide crescent or a semi
calcaneal tuberosity is the primary weightbearing portion of the cal circle rather than a triangle. Dorsal talonavicular, cuneonavicular and
caneus. Clinically, pain over the medial tuberosity is often associated cubonavicular ligaments are attached to the dorsal navicular surface.
with plantar fasciitis (Yi et al 2011). Abductor digiti minimi is attached
to the lateral process, extending medially to the medial process. The Muscle and ligamentous attachments The navicular tuberosity
long plantar ligament is attached to the rough region between the pro is the main attachment of tibialis posterior, and a groove lateral to it
cesses proximally, and extends to the anterior tubercle distally. The transmits part of the tendon distally to the cuneiforms and middle three
plantar calcaneocuboid ligament (short plantar ligament) is attached metatarsal bases. The plantar calcaneonavicular ligament is attached to | 1,951 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Calcaneal apophysitis (Sever’s disease) is a selflimiting inflamma
tory condition seen in some child athletes, boys more commonly than
girls. It is not a true apophysitis and the use of imaging for its initial
diagnosis is a subject of controversy (Kose 2010, Rachel et al 2011).
Calcaneal apophysitis is often treated with stretching, therapeutic heel
lifts, icing and nonsteroidal antiinflammatory drugs (Micheli and
Ireland 1987).
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Second metatarsal Fig. 84.11 The skeleton
Third metatarsal of the tarsals and
metatarsals, dorsal
aspect. (With permission
from Waschke J, Paulsen
Fourth metatarsal F (eds), Sobotta Atlas of
Human Anatomy, 15th ed,
Elsevier, Urban & Fischer.
First metatarsal
Copyright 2013.)
I
II
III
Head
IV
Tuberosity of first metatarsal
V
Fifth metatarsal Shaft Medial cuneiform
Intermediate cuneiform
Base
Tuberosity Lateral cuneiform
Groove for tendon
of fibularis longus Navicular
Tuberosity
Cuboid Tuberosity
metatarsal part
Calcaneal articular facet
a slight projection lateral to the groove and adjacent to the proximal Cuboid
surface. The calcaneonavicular part of the bifurcate ligament is attached
The cuboid, the most lateral bone in the distal tarsal row, lies between
to the rough part of the lateral surface (see Fig. 84.5B).
the calcaneus proximally and the fourth and fifth metatarsals distally
(see Figs 84.8A, 84.11). Its dorsolateral surface is rough for the attach
Vascular supply The dorsal aspect of the navicular is supplied either
ment of ligaments. The plantar surface is crossed distally by an
from a branch of, or directly from, the dorsalis pedis artery. The medial
oblique groove for the tendon of fibularis longus and bounded proxi
plantar artery supplies its plantar aspect, and the tuberosity is supplied
mally by a ridge that ends laterally in the tuberosity of the cuboid,
by an anastomosis between the dorsalis pedis and medial plantar
the lateral aspect of which is faceted for a sesamoid bone or cartilage
arteries.
that is frequently found in the tendon of fibularis longus. Proximal to
its ridge, the rough plantar surface extends proximally and medially
Innervation The navicular is innervated by the deep fibular and
because of the obliquity of the calcaneocuboid joint, making its
medial plantar nerves.
medial border much longer than the lateral. The lateral surface is
rough; the groove for fibularis longus extends from a deep notch on
Ossification The navicular ossification centre appears during the
its plantar edge. The medial surface, which is much more extensive
third year (see Fig. 84.7). It is sometimes affected by avascular necrosis
and partly nonarticular, bears an oval facet for articulation with the
between the ages of 4 and 7 years (Köhler’s disease). An accessory
lateral cuneiform, and proximal to this another facet (sometimes
navicular bone, which is considered an anatomical variant, occasionally
absent) for articulation with the navicular; the two form a continuous
occurs. It arises from a separate ossification centre in the region of the
surface separated by a smooth vertical ridge. The distal surface is
posteromedial aspect of the navicular tuberosity. There are three distinct
divided vertically into a medial quadrilateral articular area for the
types of accessory navicular. Type I is probably a sesamoid bone within
base of the fourth metatarsal and a lateral triangular area, its apex
the plantar aspect of the tendon of tibialis posterior at the level of the
lateral, for the base of the fifth metatarsal. The proximal surface, trian
inferior calcaneonavicular ligament. In type II, the accessory bone is
gular and concavoconvex, articulates with the distal calcaneal surface;
separated from the body of the navicular by a synchondrosis. These
its medial plantar angle projects proximally and inferiorly to the
types are sometimes known as os tibiale externum or naviculare
distal end of the calcaneus.
secundarium. Type III is commonly called the cornuate navicular or
gorilloid navicular (Barnes 2003), where the accessory bone is united
Muscle and ligamentous attachments The dorsal calcaneo
to the navicular by a bony ridge, and may represent the possible end
cuboid, cubonavicular, cuneocuboid and cubometatarsal ligaments are
stage of type II. An accessory navicular may be the source of pain in
attached to the dorsal surface. Deep fibres of the long plantar ligament
athletes. Type II is the most commonly symptomatic variant; it has been
are attached to the proximal edge of the plantar ridge. Slips from the
suggested that the pull of the tendon of tibialis posterior, the degree of
tendons of tibialis posterior and flexor hallucis brevis are attached to
foot pronation, and the location of the accessory bone in relation to
the projecting proximomedial part of the plantar surface. Interosseous,
the undersurface of the navicular may produce tension, shear and/or
cuneocuboid and cubonavicular ligaments are attached to the rough
compression forces on the synchondrosis. An accessory navicular is one
part of the medial cuboidal surface. Proximally, the medial calcane
aetiology of posterior tibial tendon dysfunction (PTTD). The altered
ocuboid ligament, which is the lateral limb of the bifurcate ligament,
mechanics cause abnormal stresses, leading to tendon degeneration,
is also attached to this surface. The placement and trapezoidal shape of
decreased strength and possible tendon rupture.
the cuboid give it the ability to act as the ‘keystone’ of the lateral lon Rarely, the navicular is bipartite and it arises from two distinct
gitudinal arch of the foot. During locomotion, the tension of the cal
centres of ossification. This can lead to premature degeneration within
caneocuboid joint helps ‘lock’ the midtarsal joint and acts as a major
the talocalcaneonavicular joint (Müller–Weiss disease). Occasionally, a
stabilizer of the foot.
small bone is found within the talocalcaneonavicular joint on its dorsal
aspect. Referred to as an os talonaviculare dorsale, it represents either a
separate accessory bone or a fractured osteophyte of the proximal dorsal Vascular supply The cuboid is supplied by deep branches of the
aspect of the navicular. A bipartite navicular is sometimes found with medial and lateral plantar arteries and by branches from the dorsal
cuneonavicular coalitions. arterial network. | 1,953 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Innervation The cuboid is innervated by branches from the lateral Muscle attachments Part of the tendon of tibialis posterior is
plantar, sural and deep fibular nerves. attached to the intermediate cuneiform.
Ossification The cuboid frequently begins to ossify before birth, the Vascular supply The intermediate cuneiform is supplied via its
primary ossification centre appearing just before birth (see Fig. 84.7). dorsal, medial and lateral surfaces, mainly from the dorsal arterial
An os cuboides secundarium is a rare accessory bone situated on the network.
plantar aspect of the cuboid and is sometimes involved in the infre
quently reported cubonavicular coalitions. Innervation The intermediate cuneiform is innervated by the deep
fibular and medial plantar nerves.
Cuneiforms
Ossification The ossification centre appears during the third year of
The wedgelike cuneiform bones articulate with the navicular proxi life (see Fig. 84.7). The os cuneo2 metatarsaleII dorsale, a rare acces
mally and with the bases of the first to third metatarsals distally; the sory bone, lies on the dorsal aspect of the joint between the intermedi
medial cuneiform is the largest, the intermediate the smallest. The ate cuneiform and the second metatarsal. It is wedgeshaped with its
dorsal surfaces of the intermediate and lateral cuneiforms form the base base orientated dorsally.
of the wedge. The wedge is reversed in the medial cuneiform, which is
Lateral cuneiform
a prime factor in shaping the transverse arch. The proximal surfaces of
all three form a concavity for the distal surface of the navicular. The The lateral cuneiform lies between the intermediate cuneiform and
medial and lateral cuneiforms project distally beyond the intermediate cuboid, and also articulates with the navicular and, distally, with the
cuneiform and so form a recess (mortise) for the second metatarsal third metatarsal base (see Figs 84.5A, 84.11). Like the intermediate
base. cuneiform, its dorsal surface, which is rough and almost rectangular, is
the base of a wedge. The plantar surface is narrow and receives a slip
Medial cuneiform from tibialis posterior and sometimes part of flexor hallucis brevis. The
The medial cuneiform (see Figs 84.5, 84.8A, 84.11) articulates with the distal surface is a triangular articular facet for the third metatarsal base.
navicular and base of the first metatarsal. It has a rough, narrow dorsal The proximal surface is rough on its plantar aspect, but its dorsal two
surface. The distal surface is a kidneyshaped facet for the first metatarsal thirds articulate with the navicular by a triangular facet. The medial
base, its ‘hilum’ being lateral. The proximal surface bears a piriform surface is partly nonarticular and has a vertical segment, indented by
facet for the navicular, which is concave vertically and dorsally nar the intermediate cuneiform, on its proximal margin; on its distal
rowed. The medial surface, rough and subcutaneous, is vertically convex; margin, a narrower strip (often two small facets) articulates with the
its distal plantar angle carries a large impression, which receives the lateral side of the second metatarsal base. The lateral surface, also partly
principal attachment of the tendon of tibialis anterior (see Fig. 84.5B). nonarticular, bears a triangular or oval proximal facet for the cuboid;
The lateral surface is partly nonarticular; there is a smooth rightangled a semilunar facet on its dorsal and distal margin articulates with the
strip along its proximal and dorsal margins for the intermediate cunei dorsal part of the medial side of the fourth metatarsal base. Non
form. Its distal dorsal area is separated by a vertical ridge from a small, articular areas of the medial and lateral surfaces receive intercuneiform
almost square, facet for articulation with the dorsal part of the medial and cuneocuboid ligaments, respectively, which are important in the
surface of the second metatarsal base. Plantar to this, the medial cunei maintenance of the transverse arch of the foot.
form is attached to the medial side of the second metatarsal base by a
strong ligament (Lisfranc’s ligament). Proximally, an intercuneiform Muscle attachments The plantar surface of the lateral cuneiform
interosseous ligament connects this surface to the intermediate cunei receives a slip from the tendon of tibialis posterior and, occasionally,
form. The distal and plantar areas of the surface are roughened by part of flexor hallucis brevis.
attachment of part of the tendon of fibularis longus.
Vascular supply The lateral cuneiform is supplied via its dor
Muscle attachments The plantar surface receives a slip from the sal, medial and lateral surfaces, mainly from the dorsal arterial
tendon of tibialis posterior, in addition to part of the insertion of the network.
tendon of fibularis longus. The medial surface receives the attachment
of most of the tendon of tibialis anterior. Innervation The lateral cuneiform is innervated by branches of the
deep fibular and lateral plantar nerves.
Vascular supply The medial cuneiform is supplied via its dorsal,
medial and lateral surfaces, mainly from the dorsal arterial network. Ossification The lateral cuneiform ossifies during the first year of life
(see Fig. 84.7).
Innervation The medial cuneiform is supplied by the deep fibular and
Tarsal coalition
medial plantar nerves.
Tarsal coalition is a hereditary condition in which there is a fibrous,
Ossification The medial cuneiform may have two separate ossific cartilaginous or osseous union of two or more tarsal bones. The
ation centres, which appear during the second year of life (see Fig. aetiology of tarsal coalition is unclear; suggestions include genetic pre
84.7). Very rarely, the medial cuneiform is bipartite and there is a hori disposition, failure of segmentation of primitive mesenchyme, trauma,
zontal cleavage plane between the two parts. arthritic changes, and/or osteochondroses of the tarsal bones (e.g.
The os cuneo1 metatarsaleI plantare is a rare accessory bone that Köhler’s disease) (Gregersen 1977, Zaw and Calder 2010, Lemley et al
occurs on the plantar aspect of the foot at the base of the first metatarsal 2006, Harris 1965, Varner and Michelson 2000).
and articulates with the plantar base of the first metatarsal and the
medial cuneiform.
METATARSUS
Intermediate cuneiform
The intermediate (middle) cuneiform articulates proximally with the The five metatarsals lie in the distal half of the foot and connect the
navicular and distally with the second metatarsal base (see Figs 84.5A, tarsus with the phalanges. Like the metacarpals, they are miniature long
84.11). It has a narrow plantar surface that receives a slip from the bones and have a shaft, proximal base and distal head. Except for the
tendon of tibialis posterior. The distal and proximal surfaces are both first and fifth, the shafts are long and slender, longitudinally convex
triangular articular facets. The medial surface is partly articular; it articu dorsally, and concave on their plantar aspects. Prismatic in section, they
lates via a smooth, angled region that is occasionally double with the taper distally. Their bases articulate with the distal tarsal row and with
medial cuneiform along its proximal and dorsal margins. The lateral adjacent metatarsal bases. The line of each tarsometatarsal joint, except
surface is also partly articular; along its proximal margin a vertical the first, inclines proximally and laterally with the metatarsal bases
segment, usually indented, abuts the lateral cuneiform. Strong interos being oblique relative to their shafts. The heads articulate with the
seous ligaments connect the nonarticular parts of both surfaces to the proximal phalanges, each by a convex surface that passes farther on to
adjacent cuneiforms. An intricate arrangement of dorsal and plantar its plantar aspect, where it ends on the summits of two eminences. The
ligaments spans the tarsometatarsal joint, connecting the most distal sides of the heads are flat, with a depression surmounted by a dorsal
row of tarsals to their respective metatarsals. However, the plantar liga tubercle for a collateral ligament of the metatarsophalangeal joint.
ment between the intermediate cuneiform and the base of the second On occasion, an os intermetatarseum is encountered between the
metatarsal is uniquely absent (Castro et al 2010, Chaney 2010, de Palma medial cuneiform and the bases of the first and second metatarsals and
et al 1997, Blouet et al 1983). represents a rare accessory bone in this region. | 1,954 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Ankle and foot
Harris and Beath (1948) were the first to recognize an association
between tarsal coalitions and ‘peroneal (fibular) spastic flat foot’. The
two most common examples are talocalcaneal and calcaneonavicular
coalitions, which usually present with symptoms early in the second
decade of life. They are often, but not invariably, associated with flat
feet (pes planus). A talonavicular coalition is rare (Brennan et al 2012),
but when present, it is often associated with a ‘ballandsocket’ ankle
joint. Surgical resection of tarsal coalitions may eradicate associated
pain but seldom improves the range of movement.
1428.e1 | 1,955 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Individual metatarsals metatarsal head starts between the third and fourth years; fusion occurs
between the seventeenth and twentieth years.
First metatarsal Third metatarsal
The first metatarsal (see Figs 84.5, 84.11) is the shortest and thickest, The third metatarsal (see Figs 84.5, 84.11) has a flat triangular base,
and has a strong shaft, of marked prismatic form. The base sometimes articulating proximally with the lateral cuneiform, medially with the
has a lateral facet or illdefined smooth area as a result of contact with second metatarsal, via dorsal and plantar facets, and laterally, via a
the second metatarsal. Its large proximal surface, usually indented on single facet, with the dorsal angle of the fourth metatarsal. The medial
the medial and lateral margins, articulates with the medial cuneiform. plantar facet is frequently absent. The third tarsometatarsal joint is
Its circumference is grooved for tarsometatarsal ligaments and, medi relatively immobile and predisposes the third metatarsal to stress
ally, part of the tendon of tibialis anterior is attached; its plantar angle fracture.
has a rough, oval, lateral prominence for the tendon of fibularis longus.
The medial head of the first dorsal interosseous is attached to the flat Muscle attachments The lateral heads of the second dorsal interos
lateral surface of the shaft. The large head has a plantar elevation, the seous and first plantar interosseous are attached to the medial surface
crista, which separates two grooved facets (of which the medial is of the shaft. The medial head of the third dorsal interosseous is attached
larger), on which sesamoid bones glide. The most common joint to its lateral surface.
deformity related to the first metatarsal is hallux valgus.
Vascular supply The blood supply of the third metatarsal is the same
Muscle attachments The first metatarsal receives attachments from as that of the second metatarsal, described above.
the tendon of tibialis anterior medially, and the tendon of fibularis
longus on its plantar aspect. It gives origin to the medial head of the Innervation The third metatarsal is innervated by the deep fibular and
first dorsal interosseus on the proximal aspect of the lateral surface. lateral plantar nerves.
Vascular supply The first metatarsal is supplied by the first dorsal Ossification There are two centres of ossification, one in the shaft
and first plantar metatarsal arteries and a superficial branch of the and one distally in the metatarsal head (see Fig. 84.7). Ossification of
medial plantar artery, which together form a periosteal arterial network. the shaft starts during the ninth prenatal week and ossification of the
A nutrient artery enters the lateral surface of the middiaphysis. The metatarsal head starts between the third and fourth years; fusion occurs
head receives a medial, lateral and plantar supply from these arteries. between the seventeenth and twentieth years.
Fourth metatarsal
Innervation The first metatarsal is innervated by the deep fibular and
The fourth metatarsal is smaller than the third (see Figs 84.5, 84.11).
medial plantar nerves.
Its base has, proximally, an oblique quadrilateral facet for articulation
Ossification The first metatarsal has two centres of ossification, one with the cuboid; laterally, a single facet for the fifth metatarsal; and
medially, an oval facet for the third metatarsal. The latter is sometimes
in the shaft and the other in the base (unlike the other metatarsals, in
divided by a ridge, in which case the proximal part articulates with the
which the secondary ossification centre is distal). They appear during
lateral cuneiform.
the tenth week of prenatal life and the third year of life, respectively
(see Fig. 84.7,) and fuse between the seventeenth and twentieth years.
Muscle attachments The lateral head of the third dorsal and
There may be a third centre in the first metatarsal head.
second plantar interossei are attached to the medial surface. The medial
Second metatarsal head of the fourth dorsal interosseous is attached to the lateral surface.
The second metatarsal is the longest (see Figs 84.5, 84.11). Its cuneiform Vascular supply The blood supply of the fourth metatarsal is the
base bears four articular facets. The proximal one, concave and triangu
same as that of the second and third metatarsals, described above.
lar, is for the intermediate cuneiform. The dorsomedial one, for the
medial cuneiform, is variable in size and usually continuous with that Innervation The fourth metatarsal is innervated by the deep fibular
for the intermediate cuneiform. Two lateral facets, dorsal and plantar,
and lateral plantar nerves.
are separated by nonarticular bone, each divided by a ridge into distal
demifacets, which articulate with the third metatarsal base, and a proxi Ossification There are two centres of ossification, one in the shaft
mal pair (sometimes continuous) for the lateral cuneiform. The areas and one distally in the metatarsal head (see Fig. 84.7). Ossification of
of these facets vary, particularly the plantar facet, which may be absent. the shaft starts during the ninth prenatal week and ossification of the
An oval pressure facet, caused by contact with the first metatarsal, may metatarsal head commences between the third and fourth years; fusion
appear on the medial side of the base, plantar to that for the medial occurs between the seventeenth and twentieth years.
cuneiform. Because of its length, its steep inclination, and the position
of its base recessed in the tarsometatarsal joint, it is at risk of stress Fifth metatarsal
overload; perhaps this is why it is a common site for stress fractures The fifth metatarsal has a tuberosity on the lateral side of its base (see
(particularly in athletes) and an avascular phenomenon in its head Figs 84.5, 84.11). The base articulates proximally with the cuboid by a
(Freiberg’s infraction). The second metatarsal head is affected in 68% triangular, oblique surface, and medially with the fourth metatarsal. The
of cases, the third metatarsal head in 27% of cases, and the fourth tuberosity can be seen and palpated midway along the lateral border
metatarsal head in 3% of cases. Freiberg’s disease is the only osteochon of the foot; in acute inversion it may be fractured. The metaphysial–
drosis more common in females and occurs at a ratio of 5 : 1 with peak diaphysial junction of the fifth metatarsal base is prone to traumatic or
age of onset between 11 and 17 years (Carmont et al 2009, Cerrato stress fractures. It is believed that fractures at this level damage the
2011). nutrient artery and the extraosseous arterial plexus, resulting in com
promised vascularity of the fracture site, consequent poor fracture
Muscle attachments The lateral head of the first dorsal interos healing and nonunion that often requires surgical fixation.
seous and the medial head of the second are attached to the medial
and lateral surfaces of the shaft, respectively. Muscle attachments The tendon of fibularis tertius is attached to
the medial part of the dorsal surface and medial border of the shaft,
Vascular supply The blood supply of the second, third and fourth and that of fibularis brevis to the dorsal surface of the tuberosity. A
metatarsals follows the same pattern as that described for the first meta strong band of the plantar aponeurosis, sometimes containing muscle,
tarsal, i.e. the bones are all supplied by branches of the dorsal and connects the apex of the tuberosity to the lateral process of the calcaneal
plantar metatarsal arteries. The nutrient artery enters the diaphysis on tuberosity. It is this attachment, and not that of fibularis brevis, that is
its lateral side near the metatarsal base. A constant plantar vessel sup responsible for avulsion fractures of the tuberosity. The tendon of
plies the heads of the metatarsals. abductor digiti minimi grooves the plantar surface of the base and flexor
digiti minimi brevis is attached here. The lateral heads of the fourth
Innervation The second metatarsal is innervated by branches of the dorsal and the third plantar interossei are attached to the medial side
deep fibular and branches of the medial plantar nerve. of the shaft.
Ossification There are two centres of ossification, one in the shaft Vascular supply The fifth metatarsal is supplied by dorsal and
and one distally in the metatarsal head (see Fig. 84.7). Ossification of plantar metatarsal arteries and an inconstant fibular marginal artery.
the shaft starts during the ninth prenatal week and ossification of the The nutrient artery enters the diaphysis proximally and medially. | 1,956 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Innervation The fifth metatarsal is innervated by branches from the 84.5). On occasion, there are only two phalanges in the little toe and,
sural, superficial fibular and lateral plantar nerves. rarely, this is the case with the other toes. The phalanges of the toes are
much shorter than their counterparts in the hand, and their shafts,
Ossification There are three centres of ossification, one at the base especially those of the proximal set, are compressed from side to side.
in the region of the tuberosity (an apophysis), one in the shaft and one In the proximal phalanges, the compressed shaft is convex dorsally,
distally in the metatarsal head. Ossification of the shaft starts during with a plantar concavity. The base is concave for articulation with a
the tenth prenatal week and ossification of the metatarsal head starts metatarsal head, and the head is a trochlea for the middle phalanx.
between the third and fourth years (see Fig. 84.7). Fusion of the distal Middle phalanges are small and short, but broader than their proximal
and shaft centres occurs between the seventeenth and twentieth years; counterparts. Distal phalanges resemble those in the fingers, but are
the proximal apophysis fuses earlier. An os vesalianum pedis is a smaller and flatter. Each has a broad base for articulation with a middle
rare variant that should not be confused with the basal apophysis phalanx and an expanded distal end. A rough tuberosity on the plantar
(Fig. 84.12). aspect of the latter supports the pulp of the toe and provides a weight
bearing area.
PHALANGES OF THE FOOT
Muscle attachments Tendons of the long digital flexors and exten
sors are attached to the plantar and dorsal aspects of the bases of the
In general, the phalanges of the foot resemble those of the hand; there
distal phalanges of the lateral four toes. Flexor hallucis longus and
are two in the great toe, and three in each of the other toes (see Fig.
extensor hallucis longus are similarly attached to the great toe. The
bases of the middle phalanges receive the tendons of flexor digitorum
A Os intercuneiforme brevis and extensor digitorum brevis. The proximal phalanges of the
Os talonaviculare dorsale second, third, fourth and fifth toes each receive a lumbrical on their
medial side; those of the second, third and fourth toes also receive an
Os trigonum
interosseous muscle on both sides. For further details of muscular,
capsular and ligamentous arrangements in the toes, refer to Figure 84.5.
The terminal phalanx of the great toe normally shows a small degree
of abduction, as may the proximal phalanx. This is presumed to be
unrelated to footwear because this degree of deviation has also been
observed in fetal specimens.
Vascular supply The proximal phalanges receive most of their blood
Os sustentaculi Pars peronea metatarsalis I supply from the dorsal digital arteries. The middle phalanges are sup
Os tibiale externum Medial sesamoid plied by plantar and dorsal digital arteries. The distal phalanges receive
their supply mainly from plantar digital arteries.
Interphalangeal sesamoid
Innervation The phalanges are innervated by the plantar and dorsal
B Os talonaviculare dorsale Os calcaneus secundarius digital nerves.
Os intercuneiforme Os trigonum Ossification Phalanges are ossified from a primary centre for the
shaft and a basal epiphysis (see Fig. 84.7). Primary centres for the distal
Os intermetatarsalis I
phalanges appear between the ninth and twelfth prenatal weeks, and
somewhat later in the fifth digit. Primary centres for the proximal
phalanges appear between the eleventh and fifteenth weeks, and later
for the middle phalanges, but there is wide variation. Basal centres
appear between the second and eighth years (usually second or third
in the great toe), and union with the shaft occurs by the eighteenth year.
There is considerable variation in ossification and fusion dates.
Os vesalianum pedis Os peroneum
SESAMOID BONES
Most sesamoid bones are only a few millimetres in diameter and their
C Second toe sesamoids Third toe sesamoids
shape is variable. Some have a predictable location (see below), but
many others vary in terms of location and frequency of occurrence (see
Fourth toe sesamoid
Fig. 84.12). Some sesamoid bones ossify, whereas others remain carti
Interphalangeal sesamoid
laginous. Most sesamoid bones are embedded in tendons in close
Lateral (fibular) sesamoid proximity to joints. Their precise role is not understood; it is believed
that they may alter the direction of muscle pull, decrease friction and
Medial (tibial) sesamoid
Fifth toe sesamoids modify pressure.
Medial and lateral sesamoid bones of the
first metatarsophalangeal joint
The two constant sesamoid bones within the foot are those of the first
Pars peronea metatarsalis I metatarsophalangeal articulation. The medial (tibial) sesamoid bone is
generally larger than the lateral (fibular) sesamoid bone and lies slightly
Sesamoid of tibialis posterior more distally. During dorsiflexion of the great toe, the sesamoid bones
Os vesalianum pedis
Os tibiale externum lie below the first metatarsal head, offering protection to the otherwise
(Os naviculare accessorium) Os peroneum exposed plantar aspect of the first metatarsal head. The medial sesamoid
is approximately 10 mm wide and 14 mm long, and the lateral sesam
Os cuboides secundarius oid is usually smaller (approximately 8 mm wide and 10 mm long);
the overall sizes of the sesamoid bones vary considerably.
The sesamoid bones are embedded within the double tendon of
flexor hallucis brevis and articulate on their dorsal surfaces with the
plantar facets of the first metatarsal head. They are separated by the
crista or intersesamoidal ridge, which provides stability to the sesamoid
Sesamoid bones
bone complex. (This ridge can be eroded to the point of obliteration
Accessory bones in severe cases of hallux valgus.) The sesamoid bones are connected to
the plantar base of the proximal phalanx through the plantar plate,
Fig. 84.12 Sites of sesamoid and accessory bones found in the left foot. which is an extension of the tendon of flexor hallucis brevis. A thin
A, Medial aspect. B, Lateral aspect. C, Plantar aspect. layer of the tendon of flexor hallucis brevis covers the plantar surface | 1,957 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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of each sesamoid, whereas the dorsal or superior surface is covered by Articulating surfaces Articular surfaces are covered by hyaline car
hyaline cartilage. The sesamoid bones are suspended by a slinglike tilage. The talar trochlear surface, which is convex sagittally and gently
mechanism made up of the collateral ligaments of the first metatarso concave transversely, is wider anteriorly; the distal tibial articular surface
phalangeal joint and the sesamoid ligaments on either side of the is reciprocally curved. The talar articular surface for the medial malleo
joint. The plantar aponeurosis also has an attachment to the sesamoid lus is a proximal area on the medial talar surface, and is fairly flat,
bones. commashaped and deeper anteriorly. The larger lateral talar articular
Approximately 30% of these sesamoid bones are bipartite. The me surface is triangular and vertically concave, while the articular surface
dial is much more commonly affected and may have two, three or four on the lateral malleolus is reciprocally curved. Posteriorly, the edge
parts, but the fibular sesamoid rarely has more than two. The condition between the trochlear and fibular articular surfaces of the talus is bevel
may be bilateral. The sesamoid bones may be congenitally absent. led to a narrow, flat triangular area that articulates with the inferior
transverse tibiofibular ligament (Fig. 84.13A); all surfaces are contigu
Muscle attachments The medial sesamoid bone receives an attach ous. The bones are held together by a fibrous capsule, and by medial
ment from abductor hallucis, which medially stabilizes the sesamoid collateral (deltoid), anterior and posterior talofibular and calcaneofibu
complex. The lateral sesamoid receives some fibres from the tendon of lar ligaments.
adductor hallucis and this provides lateral stabilization. The medial and
lateral sesamoid bones are connected by the intersesamoid ligament,
Fibrous capsule Around the joint, the fibrous capsule is thin in front
which forms the floor of the tendinous canal for the tendon of flexor
and behind. It is attached proximally to the borders of the tibial and
hallucis longus.
malleolar articular surfaces, and distally to the talus near the margins
Vascular supply There are three patterns of blood supply to the of its trochlear surface, except anteriorly where it reaches the dorsum
of the talar neck. The capsule is strengthened by strong collateral liga
sesamoid bones. In 50% of cases, the arterial supply is derived from the
ments. Its posterior part consists mainly of transverse fibres. It blends
medial plantar artery and the deep plantar arch; in 25% of cases, it is
with the inferior transverse ligament and is thickened laterally where it
predominantly from the deep plantar arch; and in 25% of cases, it is
reaches the fibular malleolar fossa.
from the medial plantar artery alone. The major arterial blood supply
to the sesamoid bones enters from the proximal and plantar aspects,
and only a minor contribution enters through their distal poles. Ligaments The ligaments of the ankle joint are the medial and lateral
collateral ligaments.
Innervation The medial and lateral sesamoid bones are innervated by
the plantar digital nerves. Medial collateral ligament (deltoid ligament) The medial collateral
ligament (deltoid ligament) is a strong, triangular band, attached to the
Ossification The ossification centres of the sesamoid bones can be apex and the anterior and posterior borders of the medial malleolus
multiple or single. (Panchani et al 2014; Fig. 84.13B). Of its superficial fibres, anterior
Other sesamoid and accessory bones (tibionavicular) fibres pass anteriorly to the navicular tuberosity, behind
which they blend with the medial margin of the plantar calcaneona
Accessory or inconstant sesamoid bones may occur under any weight
vicular ligament; intermediate (tibiocalcaneal) fibres descend almost
bearing surface of the foot but are most common under the second to
vertically to the entire length of the sustentaculum tali; posterior (super
fifth metatarsal heads. They are extremely variable in size and their
ficial posterior tibiotalar) fibres pass posterolaterally to the medial side
incidence is difficult to determine.
of the talus and its medial tubercle; and additional fibres posterior to
A true sesamoid bone occasionally occurs in the tendon of tibialis
the sustentaculum tali have been reported (Panchani et al 2014). Of its
posterior. It lies on the plantar aspect of the navicular tuberosity within
deep fibres, anterior (anterior tibiotalar) fibres pass from the medial
the tendon at the level of the inferior border of the calcaneonavicular
malleolus to the nonarticular part of the medial talar surface; interme
ligament (see above, accessory naviculars). Very rarely, a sesamoid bone
diate fibres deep to the tibiocalcaneal ligament descend almost verti
is found within the tendon of tibialis anterior near its insertion at the
cally to the entire length of the sustentaculum tali; posterior (deep
level of the anteroinferior corner of the medial cuneiform, where there
posterior tibiotalar) fibres pass posterolaterally to the medial side of the
is an articular facet. An os peroneum is a sesamoid bone within the
talus and its medial tubercle; and additional fibres may pass to the
tendon of fibularis longus that articulates with the lateral surface of the
spring ligament (Pankovich and Shivaram 1979, Milner and Soames
calcaneus, the calcaneocuboid joint or, more frequently, the plantar
1998, Boss and Hintermann 2002). The tendons of tibialis posterior
aspect of the cuboid where there is an articular facet. The bone is situ
and flexor digitorum longus cross the ligament. The medial collateral
ated where the tendon of fibularis longus angles around the plantar
ligament of the ankle is rarely injured alone: tears are commonly associ
aspect of the lateral border of the cuboid and is usually cartilaginous.
ated with a fracture of the distal fibula. Chronic instability is rare.
The frequency of the os peroneum has been reported to be as low as
4.7% and as high as 90% (Coskun et al 2009, Oyedele et al 2006,
Lateral collateral ligament The lateral collateral ligament has three
Muehleman et al 2009).
discrete parts. The anterior talofibular ligament extends anteromedially
from the anterior margin of the lateral malleolus to the talus, attached
JOINTS anterior to its lateral articular facet and to the lateral aspect of its neck
(Fig. 84.13C). The posterior talofibular ligament runs almost horizon
ANKLE (TALOCRURAL) JOINT tally from the distal part of the lateral malleolar fossa to the lateral
tubercle of the posterior talar process (see Fig. 84.13A); a ‘tibial slip’ of
fibres, also known as transverse fibres of the posterior talofibular liga
The ankle joint is a hinge joint, approximately uniaxial. The lower end
ment, connects it to the medial malleolus. The calcaneofibular liga
of the tibia and its medial malleolus, together with the lateral malleolus
ment, a long cord, runs from a depression anterior to the apex of the
of the fibula and inferior transverse tibiofibular ligament, form a deep
lateral malleolus to a tubercle on the lateral calcaneal surface and is
recess (‘mortise’) for the body of the talus. Although it appears to be a
crossed by the tendons of fibularis longus and brevis (see Fig. 84.13A,C).
simple hinge, its axis of rotation is dynamic, shifting during dorsiflexion
The lateral ligament complex – more specifically, the anterior talofibular
and plantar flexion. Starting from the plantigrade position, the normal
ligament – is injured most commonly with inversion sprains; the pos
range of dorsiflexion is 10° when the knee is straight, and 30° with the
terior talofibular ligament is almost always spared. Although the result
knee flexed (when the calcaneal tendon will be relaxed). The range of
ing increased laxity is tolerated in most cases, some require surgical
normal plantar flexion is 30°. (The values of these ranges are all approx
reconstruction.
imate.) Dorsiflexion results in the joint adopting the ‘closepacked’
position, with maximal congruence and ligamentous tension; from this
position, all major thrusting movements are exerted, in walking, Synovial membrane The joint is lined by a synovial membrane,
running and jumping. The malleoli grip the talus, and even in relaxa which projects into the inferior tibiofibular joint.
tion, no appreciable lateral movement can occur without stretch of the
inferior tibiofibular syndesmosis. The superior talar surface is broader Vascular supply and lymphatic drainage The ankle joint is
in front, and in dorsiflexion, the malleolar gap is increased by slight supplied by malleolar branches of the anterior and posterior tibial and
lateral rotation of the fibula, by ‘give’ at the inferior tibiofibular syn fibular arteries. Lymphatic drainage is via vessels accompanying the
desmosis and gliding at the superior tibiofibular joint. Normal ankles arteries and via the long and small saphenous veins, superficially.
show valgus inclination at birth. The morphology changes in the first
few years of life and the ankle reaches the adult position by the age of Innervation The ankle joint is innervated by branches from the
three years (Nakai et al 2000). deep fibular, saphenous, sural and tibial nerves (or medial and lateral | 1,958 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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A
Posterior tibiofibular Tibial slip of posterior talofibular ligament
ligament
Groove for tibialis posterior
Inferior transverse
tibiofibular ligament
Medial malleolus
C Anterior tibiofibular ligament
Posterior tibiotalar
Parts of
Lateral malleolus deltoid ligament Posterior tibiofibular
Tibiocalcaneal
ligament
Posterior Anterior talofibular ligament
talofibular ligament Posterior process of talus
Talonavicular ligament
Posterior talofibular
Groove for flexor ligament
Calcaneofibular ligament hallucis longus Dorsal cuneonavicular
ligaments
Dorsal cuneocuboid Calcaneofibular
ligament ligament
Dorsal tarsometatarsal
ligaments
Dorsal intermetatarsal
ligaments
B
Posterior
tibiotalar Dorsal tarsometatarsal Bifurcate Cervical ligament
Sup de er lf ti oc ii da l lip ga ar mts e o nf t Tibio- Talonavicular ligament ligaments ligament Long plantar ligament
calcaneal
Dorsal cuneonavicular ligaments Dorsal cuboidonavicular ligament
Tibio-
navicular
Sustentaculum tali
Dorsal
Ligaments of first
tarsometatarsal joint
Plantar
First metatarsal
Plantar calcaneonavicular Long plantar Tuberosity of navicular
(spring) ligament ligament
Fig. 84.13 The left ankle and tarsal joints. A, Posterior aspect. B, Medial aspect. C, Lateral aspect.
plantar nerves, depending on the level of division of the tibial nerve). Factors maintaining stability Passive stability is conferred upon
Occasionally, the superficial fibular nerve also supplies the ankle the ankle mainly by the medial and lateral ligament complexes, the
joint. distal tibiofibular ligaments, the tendons crossing the joint, the bony
For a comprehensive account of the innervation of the ankle joint contours and the capsular attachments. Gravity, muscle action and
(and other foot joints), see Gardner and Gray (1968) and Sarrafian ground reaction forces provide dynamic stability. Stability requires the
(2011). continuous action of soleus assisted by gastrocnemius; it increases
when leaning forwards, and decreases when leaning backwards. If back
Relations Anteriorly, from medial to lateral, are tibialis anterior, ward sway takes the projection of the centre of gravity (‘weight line’)
extensor hallucis longus, the anterior tibial vessels, deep fibular nerve, posterior to the transverse axes of the ankle joints, the muscles that
extensor digitorum longus and fibularis tertius; posteromedially, from plantar flex and dorsiflex relax and contract, respectively.
medial to lateral, are tibialis posterior, flexor digitorum longus, the Failure of the fibular muscles can lead progressively to varus instabil
posterior tibial vessels, tibial nerve and flexor hallucis longus; in the ity of the ankle, whereas longstanding failure of the tendon of tibialis
groove behind the lateral malleolus are the tendons of fibularis longus posterior, posterior tibial tendon dysfunction, can result in valgus insta
and brevis. The tendon of fibularis brevis lies anterior to the tendon of bility of the ankle and particularly a planovalgus foot deformity com
fibularis longus at this level (Fig. 84.14). The long saphenous vein and monly referred to as adult acquired flatfoot deformity.
saphenous nerve cross the ankle joint medial to the tendon of tibialis
anterior and anterior to the medial malleolus, the nerve lying posterior Posterior tibial tendon dysfunction
to the vein.
All of the above structures are at risk during surgery on the ankle; Available with the Gray’s Anatomy e-book
the main structures at risk are the neurovascular structures located
anteriorly and posteromedially. Branches of the superficial fibular nerve Muscles producing movement Dorsiflexion is produced by tibi
are at risk of injury on the anterolateral aspect of the ankle, particularly alis anterior, assisted by extensors digitorum longus and hallucis longus,
during ankle arthroscopy. and fibularis tertius. Plantar flexion is produced by gastrocnemius and | 1,959 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Ankle and foot
The aetiology of posterior tibial tendon dysfunction is complex. The
incidence is greater in obese, middleaged women. There are multiple
contributory factors such as diabetes mellitus and hypertension, which
are further complicated by steroid exposure or previous trauma or
surgery in the region of the tendon of tibialis posterior. There is often
a progressive disruption not only of this tendon, but also of multiple
ligamentous complexes such as the spring ligament and those support
ing the naviculocuneiform and tarsometatarsal ligaments. This leads to
a marked collapse of the medial longitudinal arch, which can be staged
using the original Johnson and Strom (1989) classification system and
that of Myerson (1997). Along with the varying methods used to diag
nose posterior tibial tendon dysfunction, a clinically important test is
the single heelrise test used in the initial stages of adult acquired flat
foot deformity (Deland 2008, Gluck et al 2010, Durrant et al 2011).
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Superficial fibular nerves Dorsalis pedis artery Extensor hallucis longus inferior transverse ligament, a thick band of yellow fibres, which crosses
from the proximal end of the lateral malleolar fossa to the posterior
Tibialis anterior
Extensor digitorum longus and border of the tibial articular surface almost to the medial malleolus.
fibularis tertius in fibrous loop of Long saphenous The ligament projects distal to the bones, in contact with the talus. Its
inferior extensor retinaculum vein colour reflects its content of yellow elastic fibres.
Deep fibular nerve
Saphenous Synovial membrane The synovial membrane of the ankle joint
nerve projects into the distal 4 mm or so of the inferior tibiofibular joint.
Talus
Vascular supply and lymphatic drainage The inferior tibiofibu
lar joint is supplied by the perforating branch of the fibular artery and
Medial lateral malleolar branches of the anterior and posterior tibial arteries.
Lateral malleolus
Lymphatic drainage is via vessels corresponding to the arteries, and via
malleolus
vessels that accompany the great and small saphenous veins.
Posterior
talofibular Tibialis posterior Innervation The inferior tibiofibular joint is innervated by branches
ligament from the deep fibular and sural nerves.
Flexor digitorum
Fibularis longus longus
and fibularis brevis Tibial nerve Relations No significant structures pass anterior to the anterior aspect
of the inferior tibiofibular joint but the superficial fibular nerve is at
Sural nerve Posterior tibial artery risk during surgery to this area. Posteriorly, the fibular artery passes over
Small saphenous vein the posterior tibiofibular ligament and is at risk in the posterolateral
approach to the fibula.
Flexor hallucis longus
Fat
Factors maintaining stability Stability is maintained in part by
the bone contours, but mainly by the dense anterior and posterior
tibiofibular and the interosseous ligaments.
Calcaneal tendon
Muscles producing movement No muscles act on the inferior
tibiofibular joint, which moves only slightly. Because of the varying
slope of the lateral surface of the body of the talus, the fibula undergoes
Fig. 84.14 A transverse section through the lower part of the left ankle a small degree of lateral rotation during dorsiflexion at the ankle, and
joint, superior aspect. this results in slight widening of the interval between the bones. Testing
for a significant disruption of this joint is usually carried out with the
soleus, assisted by plantaris, tibialis posterior, flexor hallucis longus and patient under anaesthesia and involves applying a lateral rotation and
flexor digitorum longus. abduction force, looking for abnormal widening of the syndesmosis.
Another helpful clinical test for evaluating a syndesmotic injury is the
Ankle fractures Ankle fractures are common and of importance Hopkinson squeeze test. This test is carried out by compressing the
because failure to achieve accurate anatomical alignment in the treat fibula to the tibia at the midpoint of the leg. An injured syndesmosis
ment of ankle fractures often results in significant longterm morbidity. will result in pain in the area of the inferior tibiofibular joint (Scheyerer
Except for very simple and nondisplaced fractures, most ankle fractures et al 2011, Hopkinson et al 1990). Excessive anterior/posterior glide of
are associated with a ligamentous injury. The direction and nature of the fibula relative to the tibia also indicates a disruption of the joint.
forces applied to the ankle correlate with the fracture pattern and con
comitant ligament injury.
TARSAL JOINTS
INFERIOR TIBIOFIBULAR JOINT Talocalcaneal joint
The inferior tibiofibular joint is usually considered a syndesmosis. It
Anterior and posterior articulations between the calcaneus and talus
consists of the anterior and posterior tibiofibular and interosseous
form a functional unit termed the talocalcaneal or subtalar joint (see
ligaments.
Fig. 84.16). The posterior articulation is referred to as the talocalcaneal
Articulating surfaces The distal tibiofibular joint is between the joint and the anterior articulation is regarded as part of the talocalca
neonavicular joint. The talocalcaneal joint is a modified multiaxial joint
rough, medial convex surface on the distal end of the fibula and the
and its permitted movements are considered together with those at
rough concave surface of the fibular notch of the tibia. These surfaces
other tarsal joints. The bones are connected by a fibrous capsule, and
are separated distally for approximately 4 mm by a synovial prolon
by lateral, medial, interosseous talocalcaneal and cervical ligaments.
gation from the ankle joint, and may be covered by articular cartilage
in their lowest parts.
Articulating surfaces The subtalar joint proper involves the concave
Fibrous capsule The inferior tibiofibular joint does not have a posterior calcaneal facet on the posterior part of the inferior surface of
the talus and the convex posterior facet on the superior surface of the
capsule.
calcaneus (Fig. 84.15).
Ligaments The ligaments of the inferior tibiofibular joint are the
anterior, interosseous and posterior ligaments. Fibrous capsule The fibrous capsule envelops the joint; its fibres are
short and attached to its articular margins.
Anterior tibiofibular ligament The anterior tibiofibular ligament is a
flat band, which descends laterally between the adjacent margins of the Ligaments The ligaments of the talocalcaneal joint are the lateral,
tibia and fibula, anterior to the syndesmosis (see Fig. 84.13C). Bassett’s medial and interosseous talocalcaneal ligaments and the cervical
ligament is a variant that presents as a lowlying slip of the ligament, ligament.
which is inserted so far distally on the fibula that it may cause irritation
of the lateral aspect of the talus; it is amenable to arthroscopic removal Lateral talocalcaneal ligament The lateral talocalcaneal ligament is a
(Subhas et al 2008). short flat fasciculus that descends obliquely and runs inferoposteriorly
from the lateral process of the talus to the lateral calcaneal surface and
Interosseous tibiofibular ligament The interosseous tibiofibular liga is attached anterosuperior to the calcaneofibular ligament.
ment is continuous with the interosseous membrane and contains
many short bands between the rough adjacent tibial and fibular sur Medial talocalcaneal ligament The medial talocalcaneal ligament con
faces; it is the strongest union between the bones. nects the medial tubercle of the talus to the posterior aspect of the
sustentaculum tali and adjacent medial surface of the calcaneus. Its
Posterior tibiofibular ligament The posterior tibiofibular ligament is fibres blend with the medial (deltoid) ligament of the ankle joint; the
stronger than the anterior, and is placed similarly on the posterior most posterior fibres line the groove for flexor hallucis longus between
aspect of the syndesmosis (see Fig. 84.13A). Its distal, deep part is the the talus and calcaneus. | 1,961 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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A Dorsal tarsometatarsal ligaments
First metatarsal
Second metatarsal
Fourth metatarsal
Fifth metatarsal
Dorsal intercuneiform
ligaments
Tuberosity of fifth metatarsal Dorsal cuneonavicular
ligaments
Dorsal cuneocuboid ligament
Cuboid
Calcaneonavicular
ligament Navicular
Bifurcate ligament
Calcaneocuboid
Plantar calcaneonavicular
ligament
ligament
Tendon of fibularis brevis
Middle talar articular surface B Anterior talofibular
ligament
Anterior talar articular surface Interosseus talocalcaneal
ligament Interosseous
Posterior talar articular talocalcaneal
surface ligament
Calcaneus
Deltoid
ligament
Calcaneofibular
ligament
Calcaneal tuberosity
Fig. 84.15 A, Disarticulated talocalcaneal and talocalcaneonavicular joints, seen from above. B, A disarticulated talus (seen from below). (With
permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
Fig. 84.16 A coronal section through the
Tibia left ankle and talocalcaneal joint (seen
Ankle joint from behind). (With permission from
Tibiofibular syndesmosis Tibia, medial malleolus Waschke J, Paulsen F (eds), Sobotta Atlas
(inferior tibiofibular joint) of Human Anatomy, 15th ed, Elsevier,
Urban & Fischer. Copyright 2013.)
Medial collateral ligament
(deltoid ligament),
Talus, body tibiocalcaneal part
Fibula, lateral malleolus
Tendon of tibialis posterior
Tendon of flexor digitorum longus
Calcaneofibular ligament
Subtalar joint (talocalcaneal joint) Flexor retinaculum
Subtalar joint (talocalcaneal joint)
Tendon of fibularis brevis Interosseus talocalcaneal ligament
Medial plantar nerve and vessels
Tendon of fibularis longus
Abductor hallucis
Calcaneus Flexor accessorius
Abductor digiti minimi Lateral plantar nerve
Plantar aponeurosis
Flexor digitorum brevis
Interosseous talocalcaneal ligament The interosseous talocalcaneal medial to the attachment of extensor digitorum brevis, from where it
ligament is a broad, flat, bilaminar transverse band in the tarsal sinus ascends medially to an inferolateral tubercle on the talar neck (Barclay
(see Fig. 84.15A; Fig. 84.16). It descends obliquely and laterally from Smith 1896). It is considered to be taut in inversion of the foot.
the sulcus tali to the calcaneal sulcus. The posterior lamina of the liga
ment is associated with the talocalcaneal joint, and the anterior lamina Synovial membrane The synovial cavity of the talocalcaneal joint
with the talocalcaneonavicular joint. Its medial fibres are taut in ever is usually quite separate and does not communicate with those of other
sion of the foot. tarsal joints. However, direct communication with the ankle joint has
been observed in rare instances.
Posterior talocalcaneal ligament The posterior talocalcaneal ligament
is attached to the plantar border of the posterior process (posterolateral Innervation The talocalcaneal joint is innervated by branches of the
tubercle) of the body of the talus. tibial, medial plantar and sural nerves.
Cervical ligament The cervical ligament is just lateral to the tarsal sinus Relations Posteromedially, in the region of the posterior aspect of
and attached to the superior calcaneal surface (see Fig. 84.13C). It is the talocalcaneal joint, and viewed from anterior to posterior, veins on | 1,962 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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either side of the posterior tibial artery, the tibial nerve and the tendon
of flexor hallucis longus are seen. These neurovascular structures are at
risk in posteromedial approaches to the ankle and talocalcaneal joints.
On the lateral side, the tendon of fibularis brevis lies anterior to the
tendon of fibularis longus, both passing behind the lateral malleolus
in proximity to the talocalcaneal joint. The sural nerve lies just posterior
to the tendons of the fibularis longus and brevis.
Factors maintaining stability Stability is conferred by the bony
Collateral ligaments
contours of the hindfoot plus the abovementioned ligaments; it is not
Plantar ligaments
known which ligaments provide the most stability. An additional liga
mentous restraint is provided by the calcaneofibular component of the
lateral ligament complex. The tendons crossing the articulation also add
stability. Deep transverse
metatarsal ligaments
Muscles producing movement Heel inversion is controlled by
tibialis anterior, tibialis posterior and the gastrocnemius–soleus First metatarsal, base
complex via the calcaneal tendon; the extrinsic flexors of the toes also
Plantar tarsometatarsal
contribute. Eversion of the foot results from the pull of fibularis longus, ligaments
brevis and tertius in addition to the extrinsic muscles that extend the
toes. Medial cuneiform
Plantar cuneonavicular Tuberosity of
Talocalcaneonavicular joint ligaments fifth metatarsal
Plantar cuboideonavicular
BarclaySmith provided an eloquent account of the talocalcaneonavicu ligament Groove for tendon
of fibularis longus
lar joint in 1896; for more recent studies, see Bonnel et al (2011) and
Bonnel et al (2013). In terms of function, and in clinical practice, it is Navicular, tuberosity Long plantar ligament
helpful to regard this complex joint as comprising two articulations, i.e. Plantar calcaneocuboid
the anterior part of the ‘subtalar’ joint and the talonavicular joint. It is Plantar calcaneonavicular ligament
a compound, multiaxial articulation. ligament
Calcaneofibular
ligament
Articulating surfaces The ovoid talar head is continuous with the Sustentaculum tali
Long plantar ligament
triplefaceted anterior area of its inferior surface. This part fits the con
cavity formed collectively by the posterior surface of the navicular, the
Medial collateral ligament
middle and anterior talar facets of the calcaneus, and the superior tibiocalcaneal part
fibrocartilaginous surface of the plantar calcaneonavicular ligament
(spring ligament). The bones are connected by a fibrous capsule and by Groove for tendon of
Calcaneal tuberosity
the talonavicular and plantar calcaneonavicular ligaments, and the cal flexor hallucis longus
caneonavicular part of the bifurcate ligament. Fig. 84.17 Ligaments on the plantar aspect of the left foot. (With
permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human
Fibrous capsule The fibrous capsule is poorly developed, except Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
posteriorly, where it is thick and blends with the anterior part of the
interosseous ligament filling the tarsal sinus.
Synovial membrane The talocalcaneonavicular joint is a synovial
Ligaments The ligaments of the talocalcaneonavicular joint are the joint whose cavity sometimes communicates with that of the talocalca
talonavicular and plantar calcaneonavicular (spring) ligaments. neal joint.
Talonavicular ligament The talonavicular ligament is a broad, thin Innervation The talocalcaneonavicular joint is innervated by the deep
band (see Fig. 84.13B,C). It connects the dorsal surfaces of the neck of fibular and medial plantar nerves.
the talus and the navicular, and is covered by extensor tendons. The
plantar calcaneonavicular ligament and the calcaneonavicular part of Relations On the medial side, from dorsal to plantar, lie the tendon
the bifurcate ligament (see Fig. 84.13C) are the plantar and lateral liga of tibialis posterior and the tendon of flexor digitorum longus above
ments of the joint, respectively. Although the calcaneus and navicular the sustentaculum tali, and the flexor hallucis longus tendon below. At
do not articulate directly, they are connected by the calcaneonavicular this point, flexor hallucis longus lies deep to the medial and lateral
part of the bifurcate ligament and the plantar calcaneonavicular plantar branches of the posterior tibial artery and tibial nerve. The latter
ligament. structures are at risk during medial approaches to the joint, e.g. resec
tion of talocalcaneal coalition. Dorsally from medial to lateral, lie the
Plantar calcaneonavicular (spring) ligament The plantar calcaneo tendons of tibialis anterior and extensor hallucis longus, the deep
navicular (spring) ligament is a broad, thick band connecting the ant fibular nerve and the dorsalis pedis artery, the muscle belly of extensor
erior margin of the sustentaculum tali to the plantar surface of the hallucis brevis passing medially and deep to the tendons of extensor
navicular (see Figs 84.13B, 84.15A; Fig. 84.17). It ties the calcaneus to digitorum longus and fibularis tertius. Structures at risk during the
the navicular below the head of the talus as part of its articular cavity dorsal approach to the talonavicular joint include the branches of the
and it maintains the medial longitudinal arch of the foot. According to superficial fibular nerve superficially and the dorsalis pedis artery and
Davis et al (1996), the spring ligament is made up of two distinct deep fibular nerve deep to the inferior extensor retinaculum.
structures: the superomedial calcaneonavicular portion and the inferior
calcaneonavicular portion. Factors maintaining stability Stability of the joint is due to a
The dorsal surface of the superomedial calcaneonavicular portion combination of factors: bony contours, the strong plantar calcaneo
has a triangular fibrocartilaginous facet on which part of the talar head navicular (spring) ligament, and the calcaneonavicular component of
rests (see Fig. 84.15A). Its plantar surface is supported medially by the the bifurcate ligament.
tendon of tibialis posterior and laterally by the tendons of flexors hal
lucis longus and digitorum longus; its medial border is blended with Muscles producing movement The muscles producing move
the anterior superficial fibres of the medial (deltoid) ligament. Jennings ment are as described above for the talocalcaneal joint.
and Christensen (2008) showed that transection of the spring ligament
leads to instability of the hindfoot, including talar head plantar flexion Calcaneocuboid joint
and adduction, consistent with pes planovalgus (adult acquired flat
foot) deformity. The inferior calcaneonavicular portion can become The calcaneocuboid joint is at the same level as the talonavicular joint
attenuated in adult acquired flatfoot deformity, and may require surgi and together they represent the transverse tarsal joint. It is a saddle
cal correction. (sellar) or biaxial joint with concavoconvex surfaces. | 1,963 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Ankle and foot
The superomedial portion is the larger of the two, and originates
from the superomedial aspect of the sustentaculum tali and the anterior
edge of the anterior facet of the calcaneus. The inferior calcaneonavicu
lar portion originates from between the middle and anterior calcaneal
facets at the anterior portion of the sustentaculum tali. Both portions
insert on the inferior surface of the midnavicular, with the supero
medial portion inserting medial to the inferior portion.
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Articulating surfaces The articular surfaces of the calcaneocuboid Relations Fibularis longus and abductor digiti minimi pass in prox
joint, which is 2 cm proximal to the tubercle on the fifth metatarsal imity to the joint, and the lateral plantar nerve passes medially. Extensor
base, are between the anterior (distal) surface of the calcaneus and the digitorum brevis overlies the lateral aspect of the joint. The sural nerve
posterior (proximal) surface of the cuboid. and the tendon of fibularis longus are at risk during approaches to an
os peroneum.
Fibrous capsule The fibrous capsule is thickened dorsally as the
dorsal calcaneocuboid ligament. The synovial cavity of this joint is Factors maintaining stability The calcaneocuboid joint only
separate, and does not communicate with those of other tarsal permits a small amount of movement; its stability reflects the bony
articulations. contours and strong ligaments described above.
Ligaments The ligaments of the calcaneocuboid joint are the bifur
Muscles producing movement Gliding occurs between the cal
cate, long plantar and plantar calcaneocuboid ligaments.
caneus and cuboid, with conjunct rotation on each other during inver
sion and eversion of the entire foot. The same muscles that act on the
Bifurcate ligament The bifurcate ligament (Chopart’s ligament) is a
talocalcaneal and talocalcaneonavicular joints bring about these
strong Yshaped band (see Fig. 84.13C). It is attached by its stem proxi
movements.
mally to the anterior part of the upper calcaneal surface, and distally it
divides into calcaneocuboid and calcaneonavicular parts. A separate
Naviculocuneiform joint
ligament, the lateral calcaneocuboid ligament, extends to the dorso
medial aspect of the cuboid, forming a main bond between the two
rows of tarsal bones; the (medial) calcaneonavicular ligament is The naviculocuneiform joint is a compound joint, often described as a
attached to the dorsolateral aspect of the navicular. plane joint.
Long plantar ligament The long plantar ligament is the longest liga Articulating surfaces The navicular articulates distally with the
ment associated with the tarsus (see Figs 84.13C, 84.17; Fig. 84.18). It cuneiform bones where the distal navicular surface is transversely
extends from the plantar surface of the calcaneus (anterior to the pro convex and divided into three facets by low ridges that are adapted to
cesses of its tuberosity) and from its anterior tubercle, to the ridge and the proximal, slightly curved surfaces of the cuneiforms.
tuberosity on the plantar surface of the cuboid. Deep fibres are attached
to the cuboid and more superficial fibres continue to the bases of the Fibrous capsule The fibrous capsule is continuous with those of the
second to fourth, and sometimes fifth, metatarsals. This ligament,
intercuneiform and cuneocuboid joints, and it is also connected to the
together with the groove on the plantar surface of the cuboid, makes a
second and third cuneometatarsal joints and intermetatarsal joints
tunnel for the tendon of fibularis longus. It is a most powerful factor
between the second to fourth metatarsals.
limiting depression of the lateral longitudinal arch.
Ligaments The ligaments of the naviculocuneiform joint are the
Plantar calcaneocuboid ligament This short ligament (see Fig. 84.17)
dorsal and plantar ligaments.
is deeper than the long plantar ligament, from which it is separated by
areolar tissue. It is a short, wide and strong band stretching from the
anterior calcaneal tubercle and the depression anterior to it, to the Dorsal and plantar ligaments The dorsal and plantar ligaments
adjoining part of the plantar surface of the cuboid; it also supports connect the navicular to each cuneiform; of the three dorsal ligaments,
the lateral longitudinal arch. one is attached to each cuneiform. The fasciculus from the navicular to
the medial cuneiform is continued as the capsule of the joint around
Synovial membrane A synovial membrane lines the calcaneocuboid its medial aspect, and then blends medially with the plantar ligament.
joint. Plantar ligaments have similar attachments and receive slips from the
tendon of tibialis posterior.
Innervation The calcaneocuboid joint is innervated on its plantar
aspect by the lateral plantar nerve, and dorsally by the sural and deep Synovial membrane The synovial membrane lines the fibrous
fibular nerves. capsule in the manner outlined above.
Tibia
Flexor hallucis longus
Extensor hallucis longus
Ankle joint Calcaneal tendon
Subtalar joint (talocalcaneal joint)
Talotarsal joint
Talocalcaneonavicular joint
Navicular Talus
Intermediate cuneiform
Tarsometatarsal joint
Tendon of fibularis longus Talocalcaneal interosseous ligament
Second metatarsal
First dorsal interosseous
Calcaneus
Calcaneal tuberosity
Proximal phalanx, base Calcaneal fat pad
Metatarsophalangeal joint
(second toe) Adductor hallucis, oblique head Long plantar ligament Plantar aponeurosis
Flexor accessorius Flexor digitorum brevis
Fig. 84.18 A sagittal section of the foot showing ankle and tarsal joints. (With permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human
Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.) | 1,965 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Innervation The naviculocuneiform joint is innervated dorsally by the tubercle of the fifth metatarsal to the tarsometatarsal joint of the
branches from the deep fibular nerve. The medial plantar nerve inner great toe, except for that between the second metatarsal and intermedi
vates the medial and intermediate naviculocuneiform joints, and the ate cuneiform, which is 2–3 mm proximal to this line (see Figs 84.5A,
lateral plantar nerve innervates the lateral naviculocuneiform joint. 84.11). Ryan et al (2012) reported that the average joint depths for the
first, second and third metatarsal–cuneiform joints were 32.3, 26.9, and
Relations The tendon of tibialis posterior sends fibres to the medial 23.6 mm, respectively.
cuneiform and crosses the joint on its medial side; it is vulnerable to
injury when a medial surgical approach is used, as are the dorsal venous Fibrous capsule The tarsometatarsal joint of the great toe has its
arch and the saphenous nerve. The tendon of tibialis anterior passes own capsule. The articular capsules and cavities of the second and third
over the dorsomedial aspect of the joint and the tendon of extensor toes are continuous with those of the intercuneiform and naviculo
hallucis longus is lateral. Running over the intermediate cuneiform, cuneiform joints, but are separated from the fourth and fifth joints by
from medial to lateral, are the deep fibular nerve, the dorsalis pedis an interosseous ligament between the lateral cuneiform and fourth
artery and extensor hallucis brevis, all of which are vulnerable during metatarsal base.
dorsal exposure of the joint. On the lateral aspect of the joint, the
superficial structures at risk are the superficial fibular nerve and the Ligaments The bones are connected by dorsal and plantar tarsometa
dorsal venous arch of the foot. tarsal and cuneometatarsal interosseous ligaments.
Muscles producing movement Movements at the naviculocunei Dorsal ligaments The dorsal ligaments are strong and flat. The first
form, cuboideonavicular, intercuneiform and cuneocuboid joints are metatarsal is joined to the medial cuneiform by an articular capsule,
slight and subtle gliding and rotational movements that occur during and the other tarsometatarsal capsules blend with the dorsal and
pronation or supination of the foot; when alterations occur in a loaded plantar ligaments. The second metatarsal receives a band from each
foot in contact with the ground, they increase suppleness when the cuneiform, the third from the lateral cuneiform, the fourth from the
forefoot is stressed, e.g. in the initial thrust of running and jumping. lateral cuneiform and the cuboid, and the fifth from the cuboid alone.
The muscles responsible for these slight movements are tibialis anterior,
tibialis posterior, fibularis longus and brevis, and the long flexors and Plantar ligaments The plantar ligaments are longitudinal and oblique
extensors of the toes. bands, and are less regular than the dorsal ligaments. Those for the first
and second metatarsals are strongest. The second and third metatarsals
Cuboideonavicular joint are joined by oblique bands to the medial cuneiform, and the fourth
and fifth metatarsals by a few fibres to the cuboid.
The cuboideonavicular joint is usually a fibrous joint, the bones being
connected by dorsal, plantar and interosseous ligaments. This syn Cuneometatarsal interosseous ligaments There are three cuneometa
desmosis is often a synovial joint that is almost plane; its articular tarsal interosseous ligaments. One (the strongest) passes from the
capsule and synovial lining are continuous with that of the naviculo lateral surface of the medial cuneiform to the adjacent angle of the
cuneiform joint. The dorsal ligament extends distolaterally, and the second metatarsal (see Fig. 84.17). Known as Lisfranc’s ligament, it is
plantar nearly transversely from the cuboid to the navicular. The inter crucial to the stability of the tarsometatarsal joint complex. Disruption
osseous ligament is made of strong transverse fibres and connects non of this ligament can lead to instability and deformity, and subsequent
articular parts of adjacent surfaces to the two bones. degenerative changes. A second ligament connects the lateral cuneiform
to the adjacent angle of the second metatarsal; it does not divide the
Intercuneiform and cuneocuboid joints joint between the second metatarsal and lateral cuneiform, and is
inconstant. A third ligament connects the lateral angle of the lateral
cuneiform to the adjacent fourth metatarsal base.
The intercuneiform and cuneocuboid joints are all synovial and approx
imately plane or slightly curved. Their articular capsules and synovial
Synovial membrane The first tarsometatarsal joint has its own
linings are continuous with those of the naviculocuneiform joints. The
capsule, with a synovial lining. The other joints are similarly arranged,
bones are connected by dorsal, plantar and interosseous ligaments (see
but there is a communication between the second and third and
Figs 84.13B,C, 84.15A).
between the fourth and fifth tarsometatarsal joints.
Ligaments The ligaments of the intercuneiform and cuneocuboid
Innervation The interosseous cuneometatarsal ligaments are inner
joints are the dorsal, plantar and interosseous ligaments.
vated dorsally via the deep fibular nerve. The plantar aspects of the
medial two joints are innervated from the medial plantar nerve, and
Dorsal and plantar ligaments The dorsal and plantar ligaments each
the plantar aspects of the lateral joints are innervated by the lateral
have three transverse bands that pass between the medial and inter
plantar nerve.
mediate cuneiforms, the intermediate and lateral cuneiforms, and the
lateral cuneiform and cuboid. The plantar ligaments receive slips from
Relations From medial to lateral, the following structures cross the
the tendon of tibialis posterior.
dorsal aspect of the tarsometatarsal joints: the saphenous nerve, the
dorsal venous arch, the tendon of extensor hallucis longus, the dorsalis
Interosseous ligaments The interosseous ligaments connect non
pedis artery, the deep fibular nerve, extensor hallucis brevis, the tendons
articular areas of adjacent surfaces and are strong agents in maintaining
of extensor digitorum longus, extensor digitorum brevis, fibularis tertius
the transverse arch.
and fibularis brevis. Branches of the superficial fibular nerve are variable
Innervation The intercuneiform and cuneocuboid joints are inner in location on the dorsum. The sural nerve lies just inferior to the
vated dorsally via the deep fibular nerve. The plantar aspect of the tendon of fibularis brevis in the subcutaneous tissues. Surgery involving
medial two joints is innervated from the medial plantar nerve, and the the tarsometatarsal joints is performed through a dorsal approach, and
plantar aspect of the lateral joints is innervated from the lateral plantar therefore all of these structures are potentially at risk of injury.
nerve.
Factors maintaining stability The major stabilizers of the tarso
Muscles producing movement The muscles producing move metatarsal joints are the associated ligaments. However, despite the
ment are as described above for the naviculocuneiform joint. strength of the ligaments, this joint complex is vulnerable to injury
because of the lack of ligamentous connection between the first and
second metatarsal bases. The medial interosseous ligament or Lisfranc’s
TARSOMETATARSAL JOINTS ligament is responsible for the telltale avulsion fracture of the second
metatarsal base, which may be the only radiographic indication of
Tarsometatarsal articulations are approximately plane synovial joints. abnormality after injury to this part of the foot. It is a highly significant
injury that is often missed; failure to recognize and treat this injury by
Articulating surfaces The first metatarsal articulates with the surgical reduction and fixation can lead to longterm disability.
medial cuneiform; the second is recessed between the medial and
lateral cuneiforms and articulates with the intermediate cuneiform; the Muscles producing movement Movements between the tarsals
third articulates with the lateral cuneiform; the fourth articulates with and metatarsals are limited to flexion and extension, except in the first
the lateral cuneiform and the cuboid; and the fifth articulates with the tarsometatarsal joint, where some abduction and rotation occur. The
cuboid. The joints are approximately on an imaginary line traced from muscles that produce this motion are tibialis anterior and fibularis | 1,966 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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longus. Flexion and extension are brought about by the long and short ments of adjoining metatarsophalangeal joints. The interossei are
flexors and extensors of the toes. Movement between the medial cunei dorsal to, and the lumbricals, digital vessels and nerves are plantar to,
form and first metatarsal, and between the fourth and fifth metatarsal these ligaments. They resemble the deep transverse metacarpal liga
bases and the cuboid, is moderate and allows the foot to adapt to ments except that, in the foot, there is a deep transverse metatarsal liga
uneven surfaces, whereas movement between the second and third ment between the plantar ligament of the second metatarsophalangeal
metatarsal bases and their corresponding cuneiforms is very limited. joint and that of the first metatarsophalangeal joint (see Fig. 84.17).
Collateral ligaments The collateral ligaments are strong cords flanking
INTERMETATARSAL JOINTS each joint. They are attached to the dorsal tubercles on the metatarsal
heads and the corresponding side of the phalangeal bases, and they
The intermetatarsal ligaments are very strong and are present between slope inferodistally. The first metatarsophalangeal joint also contains
all the lateral four metatarsals; they are absent between the first and metatarsosesamoid ligaments. On either side, the ligaments arise from
second metatarsals. The base of the second metatarsal is joined to the metatarsal head with a narrow origin and then fan out to insert on
the first tarsometatarsal joint by the cuneometatarsal interosseous the border of the proximal phalanx and the plantar plate. Each collat
ligament. eral ligament consists of the phalangeal collateral ligament, which
inserts into the base of the proximal phalanx, and the accessory col
Ligaments The ligaments of the intermetatarsal joints include the lateral ligament, which inserts into the plantar plate.
dorsal and plantar intermetatarsal ligaments.
Synovial membrane Each metatarsophalangeal joint is a separate
Dorsal and plantar intermetatarsal ligaments As with their dorsal synovial joint.
counterparts, the plantar intermetatarsal ligaments are longitudinal,
oblique or transverse and they vary considerably in both number and Innervation The main nerve supply of the metatarsophalangeal joints
organization. The plantar ligaments are significantly stronger than the is from the plantar digital nerves, which supply the first, second, third
corresponding dorsal ligaments. The strongest is the second oblique and medial half of the fourth metatarsophalangeal joint on their plantar
plantar ligament, which connects the medial cuneiform to the bases of aspects. Digital branches of the lateral plantar nerve supply the lateral
the second and third metatarsals. half of the fourth joint, and both medial and lateral aspects of the fifth
joint, on their plantar sides. The medial dorsal cutaneous branch of the
Other ligaments All the metatarsal heads are connected indirectly by superficial fibular nerve supplies the dorsomedial side of the hallucal
deep transverse metatarsal ligaments. Dorsal and plantar ligaments pass metatarsophalangeal joint. The deep fibular nerve supplies the dorso
transversely between adjacent bases; interosseous ligaments are strong lateral side of the hallucal metatarsophalangeal joint and the medial
transverse bands that connect nonarticular parts of the adjacent sur side of the metatarsophalangeal joint of the second toe.
faces (see Fig. 84.17).
Relations Dorsally, the tendon of extensor hallucis longus lies medial
to the tendon of extensor hallucis brevis. The same arrangement occurs
METATARSOPHALANGEAL JOINTS in the lateral four toes with the tendons of extensor digitorum longus
and brevis. The interossei are plantarmedial and plantarlateral, dorsal
Metatarsophalangeal articulations are ovoid or ellipsoid joints between to the transverse intermetatarsal ligament, whereas the lumbrical ten
the rounded metatarsal heads and shallow cavities on the proximal dons and the digital artery and nerve are plantar to the transverse
phalangeal bases. They are usually 2.5 cm proximal to the web spaces intermetatarsal ligament. The extrinsic and intrinsic flexors lie on the
of the toes. plantar aspect of the joint in the midline. If approaching the metatar
sophalangeal joint surgically from the plantar surface, it is important
Articulating surfaces Articular surfaces cover the distal and plantar, not to stray from the midline.
but not the dorsal, aspects of the metatarsal heads. The plantar aspect
of the first metatarsal head has two longitudinal grooves separated by Factors maintaining stability The first metatarsophalangeal joint
a ridge (the crista). Each articulates with a sesamoid bone embedded owes its stability to its capsuloligamentous structures, and to flexor and
in the capsule of the joint, formed here by the two tendons of flexor extensor hallucis brevis, with a small contribution from flexor and
hallucis brevis. The sesamoid bones are connected to each other by the extensor hallucis longus or the bony contours. The collateral ligaments
intersesamoid ligament, which forms the floor of the tendinous canal and plantar plates stabilize the metatarsophalangeal joints of the lateral
for the tendon of flexor hallucis longus. The medial sesamoid bone four toes. Rupture of the plantar plate can lead to dislocation of the
receives an attachment from abductor hallucis and the lateral sesamoid metatarsophalangeal joint and, possibly, hammer toe deformity.
bone receives an attachment from adductor hallucis, forming the con
joint tendon. Muscles producing movement The types of movements that
Articular areas on the proximal phalangeal bases are concave. occur at these joints are like those that occur at the corresponding joints
The ligaments are capsular, plantar, deep transverse metatarsal and in the hand, but the range of movement is quite different. In contrast
collateral. to the metacarpophalangeal joints, the range of active extension that
can occur at the metatarsophalangeal joints (50–60°) is greater than
Fibrous capsules Fibrous capsules are attached to their articular that of flexion (30–40°); this is an adaptation to the needs of walking,
margins. They are thin dorsally, and may be separated from the extrinsic and is most marked in the joint of the great toe, where flexion is a few
extensor tendons by small bursae, or they may be replaced by the degrees while extension may reach 90°. When the foot is on the ground,
tendons, but they are inseparable from the plantar and collateral liga metatarsophalangeal joints are already extended to at least 25° because
ments. The plantar aponeurosis blends with the plantar capsule to form the metatarsals incline proximally in the longitudinal arches of the foot
the socalled ‘plantar plate’, which inserts distally into the base of the (see Fig. 84.8A). The range of passive movements in these joints is 90°
proximal phalanx via medial and lateral bundles. Proximally, the plate (extension) and 45° (flexion), according to Kapandji (2011). The fol
is attached to the metatarsal head via a thin synovial fold. It also receives lowing muscles produce movements at the metatarsophalangeal joints:
an attachment from the accessory collateral ligament.
Flexion Flexor digitorum brevis, lumbricals and interossei, assisted by
Ligaments The ligaments of the metatarsophalangeal joints are the flexor digitorum longus and flexor accessorius. In the fifth toe, flexor
plantar, deep transverse metatarsal and collateral ligaments. digiti minimi brevis assists. For the great toe, flexors hallucis longus and
brevis and the oblique head of the adductor hallucis are the only flexors.
Plantar ligaments The plantar ligaments are thick and dense. They lie
between and blend with the collateral ligaments, being loosely attached Extension Extensors digitorum longus and extensor digitorum brevis,
to the metatarsals and firmly attached to the phalangeal bases. Their extensor hallucis longus.
margins blend with the deep transverse metatarsal ligaments. Their
plantar surfaces are grooved for the flexor tendons, the fibrous sheaths Adduction Adductor hallucis; in the third to fifth toes, the first, second
of which connect with the edges of the grooves, and their deep surfaces and third plantar interossei, respectively.
extend the articular areas for metatarsal heads.
Abduction Abductor hallucis; in the second toe, the first and second
Deep transverse metatarsal ligaments The deep transverse metatarsal dorsal interossei; in the third and fourth toes, the corresponding dorsal
ligaments are four short, wide, flat bands that unite the plantar liga interossei; in the fifth toe, abductor digiti minimi. | 1,967 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Note that the line of reference for adduction and abduction is along (Hicks 1954). Dorsiflexion, especially of the great toe, draws the two
the second digit, which has the least mobile metatarsal. The second toe pillars together, thus heightening the arch: the socalled ‘windlass’
may therefore be ‘abducted’ medially and laterally by the first and mechanism. Next in importance is the spring ligament, which supports
second dorsal interossei, respectively. the head of the talus. If this ligament fails, the navicular and calcaneus
separate, allowing the talar head, which is the highest point of the arch,
Hallux valgus Hallux valgus is a common condition, occurring to descend, leading to a flatfoot deformity. The talocalcaneal ligaments
mainly in individuals who have a genetic predisposition. Footwear is and the anterior fibres of the deltoid ligament, from the tibia to the
implicated in the condition, which presumably accounts for the greater navicular, also contribute to the stability of the arch.
incidence in females. Metatarsus primus varus, an adduction deformity Muscles play a role in the maintenance of the medial longitudinal
of the first metatarsal, is commonly associated with hallux valgus. arch. Flexor hallucis longus acts as a bowstring. Flexor digitorum longus,
The more spheroidal the shape of the first metatarsal head, the more abductor hallucis and the medial half of flexor digitorum brevis also
likely it is to be unstable. Conversely, a flat metatarsal head is less likely contribute but to a lesser extent. Tibialis posterior and anterior invert
to be associated with hallux valgus. No muscle inserts into the first and adduct the foot, and so help to raise its medial border. The impor
metatarsal head, and therefore its position is determined by the posi tance of tibialis posterior is manifest by the collapse of the medial
tion of the proximal phalanx. As the proximal phalanx moves laterally longitudinal arch that accompanies failure of its tendon (see below).
on the metatarsal head, it pushes the head medially. This leads to
attenuation of the medial soft tissue structures and contracture of the Lateral longitudinal arch
lateral ones. The sesamoid sling (i.e. plantar plate and flexor hallucis
brevis), which is anchored laterally by adductor hallucis, remains in
The lateral longitudinal arch is a much less pronounced arch than the
place as the head moves medially, displacing the sesamoid bones from
medial one. The bones making up the lateral longitudinal arch are the
beneath the metatarsal head. As this happens, the weakest point of the
calcaneus, the cuboid and the fourth and fifth metatarsals; they con
medial capsule fails, so that abductor hallucis slips under the metatarsal
tribute little to the arch in terms of stability (see Fig. 84.8A). The pillars
head. This leads to failure of the intrinsic muscles to stabilize the joint,
are the calcaneus posteriorly and the lateral two metatarsal heads ant
and the pull of abductor hallucis leads to spinning of the proximal
eriorly. Ligaments play a more important role in stabilizing the arch,
phalanx, which results in a varus deformity. Failure to intervene surgi
especially the lateral part of the plantar aponeurosis and the long and
cally inevitably results in a progressive deformity.
short plantar ligaments. However, the tendon of fibularis longus makes
the most important contribution to the maintenance of the lateral arch.
INTERPHALANGEAL JOINTS The lateral two tendons of flexor digitorum longus (and flexor acces
sorius), the muscles of the first layer (lateral half of flexor digitorum
brevis and abductor digiti minimi), and fibularis brevis and tertius also
Interphalangeal articulations are almost pure hinge joints, in which the
contribute to the maintenance of the lateral longitudinal arch.
trochlear surfaces on the phalangeal heads articulate with reciprocally
curved surfaces on adjacent phalangeal bases. Each has an articular
Transverse arch
capsule and two collateral ligaments, as occurs in the metatarsophalan
geal joints. The plantar surface of the capsule is a thickened fibrous
plate, like the plantar metatarsophalangeal ligaments, and is often The bones involved in the transverse arch are the bases of the five meta
termed the plantar ligament. tarsals, the cuboid and the cuneiforms (see Fig. 84.8A). The intermedi
ate and lateral cuneiforms are wedgeshaped and thus adapted to
Innervation The interphalangeal articulations are innervated by maintenance of the transverse arch. The ligaments, which bind the
branches from the plantar digital nerves. The medial dorsal cutaneous cuneiforms and the metatarsal bases, mainly provide the stability of the
branch of the superficial fibular nerve also supplies the interphalangeal arch, as does the tendon of fibularis longus, which tends to approximate
joint of the great toe. Branches of the deep fibular, intermediate dorsal the medial and lateral borders of the foot. A shallow arch is maintained
cutaneous and sural nerves sometimes supply the joints of the lateral at the metatarsal heads by the deep transverse ligaments, transverse
four toes. fibres that tie together the digital slips of the plantar aponeurosis, and,
to a lesser extent, by the transverse head of adductor hallucis.
Muscles producing movement Movements are flexion and exten
sion, which are greater in amplitude between the proximal and middle Pes planus and pes cavus
phalanges than between the middle and distal. Flexion is marked, but
extension is limited by tension of the flexor muscles and plantar liga The term pes planus denotes an excessively flat foot. There is no precise
ments. Abduction, adduction and rotation occur to a minor extent. The degree of flatness that defines pes planus but it may be either physiologi
following muscles produce movements at the interphalangeal joints: cal or pathological. In physiological pes planus, the feet are flexible and
rarely problematic. There is a high prevalence in children of preschool
Flexion Flexor digitorum longus, flexor digitorum brevis, and flexor age. In the age group 2–6 years, normal arch volumes in the sitting and
hallucis longus. Flexor accessorius assists flexor digitorum longus to standing positions correlate with the height of the navicular (lowest
maintain an extended toe and neutralize the medial pull of flexor digi palpable medial projection of the navicular to the floor (Chang et al
torum longus. 2012)). In marked contrast, pathological pes planus is often associated
with stiffness and pain. The windlass (or ‘Jack’s great toe’) test involves
Extension Extensor digitorum longus, extensor digitorum brevis, exten passively dorsiflexing the great toe at the metatarsophalangeal joint.
sor hallucis longus and extensor hallucis brevis. This tightens the plantar aponeurosis and, in flexible pes planus, results
in accentuation of the medial longitudinal arch. In pathological pes
ARCHES OF THE FOOT planus, no accentuation of the arch is seen. This test can also be carried
out by asking the individual to stand with both feet plantar flexed while
viewing the hindfoot from behind. In flexible flat feet, the calcaneus
Three main arches are recognized in the foot. They are the medial lon swings into a varus position; in pathological pes planus it does not.
gitudinal, the lateral longitudinal and the transverse arches. The roles Causes of pathological pes planus include tarsal coalition, disruption
of the arches of the foot in standing, walking and running are discussed of the tendon of tibialis posterior, rupture of the spring ligament, tar
later in this chapter. sometatarsal arthritis (and subsequent collapse), and hindfoot (talocal
caneal or subtalar joint) degenerative or inflammatory arthritis.
Medial longitudinal arch
Pes cavus denotes an excessively higharched foot. The majority of
cases arise as a result of a neurological disorder (e.g. Charcot–Marie–
The medial margin of the foot arches up between the heel proximally Tooth disease, tethered spinal cord, poliomyelitis). According to the
and the medial three metatarsophalangeal joints to form a visible arch anatomical location of the deformity, pes cavus may be classified into
(see Fig. 84.8A). It is made up of the calcaneus, talar head, navicular, hindfoot, midfoot or forefoot cavus. When pes cavus involves all three
the three cuneiforms and the medial three metatarsals. The posterior parts of the foot, it is called ‘global’ cavus.
and anterior pillars are the posterior part of the inferior calcaneal surface In Charcot–Marie–Tooth disease, an overactive fibularis longus leads
and the three metatarsal heads, respectively. The bones themselves con to plantar hyperflexion of the first metatarsal. To keep the forefoot in
tribute little to the stability of the arch, whereas the ligaments contribute contact with the ground, the patient develops a progressive compens
significantly. The most important ligamentous structure is the plantar atory hindfoot varus. If ignored, the hindfoot varus, which is initially
aponeurosis, which acts as a tie beam between the supporting pillars flexible, becomes fixed. | 1,968 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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section (Ahmed et al 1998, Zantop et al 2003, Chen et al 2009). The
MUSCLES
posterior tibial artery primarily supplies the proximal and distal sec
tions, and the midsection receives a relatively poor blood supply from
The muscles acting on the foot may be divided into extrinsic and intrin the fibular artery (Chen et al 2009). These findings support previous
sic groups. work showing that the hypovascular midsection of the calcaneal
tendon is the area most prone to rupture and also underscore the
importance of avoiding disruption of the vascular supply to the tendon
EXTRINSIC MUSCLES
during percutaneous surgery. The vascularity of the skin overlying the
calcaneal tendon varies according to location: the skin on the medial
The extrinsic muscles are described in Chapter 83. Their tendons cross side of the tendon is supplied by the posterior tibial artery and on the
the ankle, and move and stabilize this joint. Distally, the tendons also lateral side by the fibular artery (Yepes et al 2010). The skin covering
act on the joints of the foot and help to stabilize them. The muscles the posterior aspect of the tendon is the most poorly vascularized;
can be grouped according to their arrangement in the leg. The extensors medial or lateral incisions of the skin surrounding the tendon should
arise in the anterior compartment of the leg and their tendons pass reduce postsurgical healing complications relative to a direct posterior
anterior to the ankle, where they are bound down by the extensor reti approach.
nacula. The lateral group arises in the relatively narrow lateral compart The calcaneal tendon is not the only plantar flexor of the ankle,
ment of the leg and their tendons pass posterior to the lateral malleolus, which is one of the reasons that ruptures of the calcaneal tendon may
bound down by the fibular retinacula. The flexors arise in the posterior not always be clinically apparent. However, it is a frequent site of
compartment of the leg and their tendons pass posterior to the ankle, pathology because of its susceptibility to rupture, degenerative change
where the tendons of the superficial group of flexors are inserted into (tendinosis) and inflammation (paratendinitis); the area of relative
the calcaneus (see below), and the tendons of the deep group of flexors avascularity in the midsubstance of the tendon is where the majority
are bound down by the flexor retinaculum. of problems occur.
Anterior group Relations The calcaneal tendon is subcutaneous. The sural nerve
crosses its lateral border about 10 cm above its insertion; the nerve is
Tibialis anterior, extensor hallucis longus, extensor digitorum longus especially vulnerable here to iatrogenic injury during surgery. Distally,
and fibularis tertius are described on pages 1406–1408. there are bursae superficial and deep to the tendon. The muscle belly
of flexor hallucis longus lies deep to the deep fascia on the anterior
Lateral group surface of the tendon.
Actions The calcaneal tendon produces plantar flexion of the ankle
Fibularis longus and fibularis brevis are described on page 1408.
joint. The tendon fibres spiral laterally through 90° as they descend, so
that the fibres associated with gastrocnemius come to insert on the bone
Posterior group
more laterally, and those associated with soleus more medially.
Superficial group Heel bursae There are three locations about the heel where bursae
Gastrocnemius, soleus and plantaris are described on pages 1409–1410; occur. The most common is the retrocalcaneal bursa, which lies between
the calcaneal tendon is described below. the calcaneal tendon and the posterior surface of the calcaneus. An
almost constant finding, it has an anterior bursal wall composed of
Calcaneal (Achilles) tendon fibrocartilage and a thin posterior wall, which blends with the thin
The calcaneal tendon is the common tendon of gastrocnemius and epitenon (epitendineum) of the calcaneal tendon. Dorsiflexion of the
soleus. It is the thickest and strongest tendon in the human body (see ankle results in compression of the bursa. Less common are an adventi
Fig. 82.3). Approximately 15 cm long, it begins near the middle of the tious bursa superficial to the calcaneal tendon, and a subcalcaneal bursa
calf; its anterior surface receives muscle fibres from soleus almost to its between the inferior surface of the calcaneus and the origin of the
inferior end. It gradually becomes more rounded until approximately plantar aponeurosis. A prominent superolateral calcaneal tuberosity
4 cm above the calcaneus; below this level, it expands and becomes may impinge on the deep aspect of the calcaneal tendon where it inserts
attached to the midpoint of the posterior surface of the calcaneus. Age on to the calcaneus (Haglund’s disease). It is often associated with a
dependent variability in the terminal insertion site of the calcaneal retrocalcaneal bursa, and symptoms are exacerbated by dorsiflexion of
tendon (Snow et al 1995, Kim et al 2010, Kim et al 2011) may explain the ankle because this movement increases the pressure within the
why calcaneal tendinopathy is infrequently found in children and adol bursa and causes impingement of calcaneus against the tendon
escents. It also has implications for the appropriate siting of surgical insertion.
entry portals about the calcaneal tendon insertion in order to reduce
the risk of iatrogenic injury to the tendon (Lohrer et al 2008). The fibres Plantaris
of the calcaneal tendon are not aligned strictly vertically and they Plantaris is described on page 1410.
display a variable degree of spiralization (Cummins and Anson 1946).
Deep group
The tendon fibres spiral laterally through 90° as they descend, so
that the fibres associated with gastrocnemius come to insert on the The deep muscles of the calf include popliteus, which acts on the knee
calcaneus more laterally, and those associated with soleus more medi joint, and flexor hallucis longus, flexor digitorum longus and tibialis
ally. The fibres in the tendon of plantaris (described in Ch. 83) exhibit posterior, which all act on the ankle joint and joints of the foot.
varying degrees of blending with the fibres of the calcaneal tendon,
sometimes blending entirely at its insertion or inserting into the plantar flexor hallucis longus
aponeurosis. Flexor hallucis longus is described on page 1411. The tendon of flexor
hallucis longus is described below.
Tensile properties The estimated tensile breaking load of a fetal
calcaneal tendon increases from 2 kg at 6 months post fertilization to flexor digitorum longus
18 kg at full term (Yamada 1970). In adults, the average estimated Flexor digitorum longus is described on page 1410.
tensile breaking load of the calcaneal tendon is 192 kg, decreasing to
160 kg in the eighth decade (Takigawa 1953), which may explain why Tibialis posterior
calcaneal tendon ruptures are infrequently encountered in youth Tibialis posterior is described on page 1412.
(Yamada 1970).
Vascular supply The blood supply to the calcaneal tendon is poor; INTRINSIC MUSCLES
the predominant artery is a recurrent branch of the posterior tibial
artery, which mainly supplies peritendinous tissues (Salmon et al The intrinsic muscles, i.e. those contained entirely within the foot,
1994). There is an additional supply from the paratenon (Carr and follow the primitive limb pattern of plantar flexors and dorsal
Norris 1989, Chen et al 2009), as well as a supply proximally from extensors.
intramuscular arterial branches and distally from the calcaneus. Micro The plantar muscles may be divided into medial, lateral and inter
dissection and angiographic studies have identified three main vascular mediate groups. The medial and lateral groups consist of the intrinsic
territories: a proximal section, a hypovascular midsection and a distal muscles of the great and fifth toes, respectively, and the central or | 1,969 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Ankle and foot
1 17
14
2 16
1
3 15
4 13
5 12 2
11
6
14
3
A
4
13
7 8 9 10 5
12
6
1 11
16
15 7
10
2
14
9
13
8
12 B
3
11
10
4
9
5
8
C
6 7
Fig. 84.19 Turbo spin-echo, T1-weighted magnetic resonance (MR) images of the left ankle of a woman aged 26. A, A coronal turbo spin-echo,
T1-weighted MR image of the forefoot through a metatarsal. Key: 1, extensor hallucis longus tendon; 2, first metatarsal; 3, adductor hallucis, oblique
head; 4, flexor hallucis (medial head); 5, flexor hallucis (lateral head); 6, flexor hallucis longus tendon; 7, flexor digitorum longus tendons; 8, third
metatarsal; 9, fourth metatarsal; 10, flexor digiti minimi brevis; 11, abductor digiti minimi; 12, fifth metatarsal; 13, dorsal interossei; 14, second metatarsal.
B, An axial turbo spin-echo, T1-weighted MR image of the ankle. Key: 1, deep fibular nerve; 2, tibia; 3, tendon of tibialis posterior; 4, tendon of flexor
digitorum longus; 5, posterior tibial artery; 6, tibial nerve (early medial and lateral plantar branching); 7, tendon of flexor hallucis longus; 8, calcaneal
tendon; 9, soleus; 10, sural nerve; 11, flexor hallucis longus; 12, fibularis brevis; 13, tendon of fibularis longus; 14, fibula; 15, extensor digitorum longus;
16, extensor hallucis longus; 17, tendon of anterior tibialis. C, A sagittal turbo spin-echo, T1-weighted MR image of the ankle and hindfoot. Key: 1, flexor
digitorum longus; 2, soleus; 3, talocalcaneal (subtalar) joint; 4, calcaneal tendon; 5, calcaneus; 6, flexor digitorum brevis; 7, flexor accessorius; 8, cuboid;
9, lateral cuneiform; 10, intermediate cuneiform; 11, navicular; 12, talocalcaneal interosseous ligament; 13, talus; 14, talocrural joint; 15, tibia; 16, tibialis
anterior. (Courtesy of Robert J. Ward, MD, Tufts University School of Medicine, Boston, MA.)
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A B
Tendon of flexor
hallucis longus
Tendinous Cruciform Tendinous sheath of
sheath of part toes
Anular
great toe
part
Tendinous
sheath of toes
Tendon of flexor Tendons of flexor
hallucis longus digitorum longus
Tendons of
First to fourth
Flexor hallucis Adductor hallucis, flexor digitorum
lumbricals
brevis transverse head brevis
Adductor hallucis,
transverse head
First to fourth
Flexor hallucis brevis
lumbricals
Third plantar
Flexor digiti
interosseus Tendon of
minimi brevis
flexor digitorum longus
Abductor digiti
Abductor digiti minimi
minimi
Plantar tendinous sheath of
Abductor hallucis
Flexor digiti minimi brevis fibularis longus
Fourth dorsal interosseus
Tendon of
Flexor digitorum brevis flexor hallucis longus
Tendon of
fibularis longus
Plantar aponeurosis Abductor hallucis
Flexor accessorius
Abductor digiti minimi
Flexor digitorum brevis
Calcaneal tuberosity
Calcaneal tuberosity
Fig. 84.20 Muscles of the sole of the foot. A, First layer. B, Second layer. (With permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human
Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
intermediate group includes the lumbricals, interossei and intrinsic Clinical anatomy Abductor hallucis fascia is strong and can be used
digital flexors. It is customary to group the muscles in four layers in soft tissue augmentation following correction of hallux valgus
because this is the order in which they are encountered during dissec deformity. Rarely, persistent, exaggerated tonus in the muscle may be a
tion. In clinical practice and in terms of function, however, the former cause of varus deformity of the foot, necessitating surgical intervention.
grouping is often more useful. The vascular supply and innervation of An abductor hallucis flap is sometimes used for provision of soft tissue
the intrinsic muscles of the foot are given at the end of this section. coverage.
Plantar muscles of the foot: first layer Flexor digitorum brevis
Attachments Flexor digitorum brevis arises by a narrow tendon from
This superficial layer includes abductor hallucis, abductor digiti minimi the medial process of the calcaneal tuberosity, from the central part of
and flexor digitorum brevis (Fig. 84.20). All three extend from the the plantar aponeurosis, and from the intermuscular septa between it
calcaneal tuberosity to the toes, and all assist in maintaining the concav and adjacent muscles (see Fig. 84.20A). It divides into four tendons,
ity of the foot. which pass to the lateral four toes; the tendons enter digital tendinous
sheaths accompanied by the tendons of flexor digitorum longus, which
Abductor hallucis
lie deep to them. At the bases of the proximal phalanges, each tendon
Attachments Abductor hallucis arises principally from the flexor divides around the corresponding tendon of flexor digitorum longus;
retinaculum, but also from the medial process of the calcaneal tuberos the two slips then reunite and partially decussate, forming a tunnel
ity, the plantar aponeurosis, and the intermuscular septum between this through which the tendon of flexor digitorum longus passes to the
muscle and flexor digitorum brevis. The muscle fibres end in a tendon distal phalanx. The tendon of flexor digitorum brevis divides again and
that is attached, together with the medial tendon of flexor hallucis attaches to both sides of the shaft of the middle phalanx. The way in
brevis, to the medial side of the base of the proximal phalanx of the which the tendon of flexor digitorum brevis divides and attaches to the
great toe. Frequently, some fibres are attached more proximally to the phalanges is identical to that of the tendons of flexor digitorum super
medial sesamoid bone of this toe. The muscle may also send some ficialis in the hand. The slip to a given toe may be absent, or it may be
fibres to the dermis along the medial border of the foot. replaced by a small muscular slip from the extrinsic flexor tendons or
from flexor accessorius. Conversely, the slip may be joined by a second,
Relations Abductor hallucis lies along the medial border of the foot supernumerary slip.
and covers the origins of the plantar vessels and nerves (Fig. 84.21).
The space created for the plantar nerves and vessels by abductor hallucis Relations Flexor digitorum brevis lies immediately deep to the central
and its relationship to the calcaneus is called the porta pedis. part of the plantar aponeurosis (see Fig. 84.20A). Its deep surface is
separated from the lateral plantar vessels and nerves by a thin layer of
Actions Abductor hallucis produces abduction of the great toe relative fascia.
to the longitudinal axis of the foot at the shaft of the second metatarsal.
Actions Flexor digitorum brevis flexes the lateral four toes at the
Testing Abductor hallucis is tested clinically by instructing the subject proximal interphalangeal joint, with equal effect in any position of the
to resist a forcibly applied lateral deviation of the proximal phalanx. ankle joint. | 1,971 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Flexor tendinous sheaths
The terminations of the tendons of the extrinsic and intrinsic flexor
muscles are contained in osseoaponeurotic canals similar to those that
occur in the fingers. These canals are bounded above by the phalanges
Tendons of and below by fibrous bands, the digital fibrous sheaths, which arch
Proper plantar digital flexor digitorum brevis across the tendons and attach on either side to the margins of the
arteries phalanges (see Fig. 84.20A). Along the proximal and middle phalanges,
the fibrous bands are strong and the fibres are transverse (anular part);
Common plantar
digital arteries opposite the joints they are much thinner and the fibres decussate
Tendon of flexor (cruciform part). Each osseoaponeurotic canal has a synovial lining,
hallucis longus which is reflected around its tendon; within this sheath, vincula tendi
Flexor hallucis Common plantar num are arranged as they are in the fingers.
brevis digital nerves
Flexor accessorius (quadratus plantae)
Tendons of flexor Attachments Flexor accessorius (quadratus plantae) arises by two
digitorum longus heads, with the long plantar ligament situated deeply in the interval
between the two heads (see Figs 84.20B, 84.19C). The medial head is
Superficial
Lateral larger and is attached to the medial concave surface of the calcaneus,
branch
plantar
below the groove for the tendon of flexor hallucis longus. The lateral
nerve
Deep branch head is flat and tendinous, and is attached to the calcaneus distal to the
Abductor hallucis
lateral process of the tuberosity, and to the long plantar ligament. The
muscle belly inserts into the tendon of flexor digitorum longus at the
Flexor accessorius point where it is bound by a fibrous slip to the tendon of flexor hallucis
longus and where it divides into its four tendons.
Cutaneous branch
Lateral plantar artery The muscle is sometimes absent altogether. Its distal attachment to
the tendons of flexor digitorum longus may vary, which means that the
Medial plantar nerve
Abductor digiti minimi fourth and fifth long flexor tendons may, at times, fail to receive slips
Flexor retinaculum from the flexor accessorius.
Plantar aponeurosis
Muscular branch
Flexor digitorum brevis Relations The medial plantar nerve passes medial to and the lateral
Posterior tibial artery plantar nerve passes superficial to flexor accessorius.
Lateral plantar nerve Actions By pulling on the tendons of flexor digitorum longus, flexor
accessorius provides a means of flexing the lateral four toes in any posi
tion of the ankle joint.
Abductor hallucis Calcaneal anastomosis
Lumbrical muscles
Attachments The lumbrical muscles are four small muscles (num
Fig. 84.21 Plantar nerves and vessels in relation to muscle layers. (With bered from the medial side of the foot) that are accessory to the tendons
permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human of flexor digitorum longus (see Fig. 84.20). They arise from these
Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.) tendons as far back as their angles of separation, each springing from
the sides of two adjacent tendons, except for the first lumbrical, which
arises only from the medial border of the first tendon. The muscles end
in tendons that pass distally on the medial sides of the four lateral toes
Testing To test the action of flexor digitorum brevis, the examiner
and are attached to the dorsal digital expansions on their proximal
passively extends the distal interphalangeal joint and asks the subject
phalanges.
to flex the toes at the proximal interphalangeal joint. Contracture of the
tendons of flexor digitorum brevis can lead to toe deformities, and
Relations The lumbricals are intimately related to the tendons of
release or lengthening procedures may be required. The muscle belly is
flexor digitorum longus before the latter enter their corresponding
sometimes excised as a flap to cover a soft tissue defect.
fibrous flexor sheaths. The lumbricals remain outside the fibrous flexor
Abductor digiti minimi sheaths and cross the plantar aspects of the deep transverse metatarsal
Attachments Abductor digiti minimi arises from both processes of ligaments before reaching the dorsal digital expansions.
the calcaneal tuberosity, from the plantar surface of the bone between
them, from the plantar aponeurosis and from the intermuscular septum Actions The lumbricals help to maintain extension of the interphalan
between the muscle and flexor digitorum brevis. Its tendon glides in a geal joints of the toes. In injuries of the tibial nerve, and in conditions
smooth groove on the plantar surface of the base of the fifth metatarsal such as the hereditary motor–sensory neuropathies (e.g. Charcot–
and is attached, with flexor digiti minimi brevis, to the lateral side of Marie–Tooth disease), lumbrical dysfunction contributes to clawing of
the base of the proximal phalanx of the fifth toe; hence it is more a the toes.
flexor than an abductor. Some of the fibres arising from the lateral
calcaneal process usually reach the tip of the tuberosity of the fifth Plantar muscles of the foot: third layer
metatarsal (see Fig. 84.5B) and may form a separate muscle: abductor
ossis metatarsi digiti quinti. An accessory slip from the base of the fifth The third layer of the foot contains the shorter intrinsic muscles of the
metatarsal is not infrequent. toes, i.e. flexor hallucis brevis, adductor hallucis and flexor digiti minimi
brevis (Fig. 84.22).
Relations Abductor digiti minimi lies along the lateral border of the
foot, and its medial margin is related to the lateral plantar vessels and Flexor hallucis brevis
nerve (see Fig. 84.21). Attachments Flexor hallucis brevis has a bifurcate tendon of origin
(see Figs 84.20, 84.22). The lateral limb arises from the medial part of
Actions Despite its name, abductor digiti minimi is more a flexor than
the plantar surface of the cuboid, posterior to the groove for the tendon
an abductor of the metatarsophalangeal joint of the fifth toe.
of fibularis longus, and from the adjacent part of the lateral cuneiform.
The medial limb has a deep attachment directly continuous with the
Plantar muscles of the foot: second layer
lateral division of the tendon of tibialis posterior, and a more superficial
attachment to the middle band of the medial intermuscular septum.
The second layer consists of flexor accessorius and the four lumbrical The belly of the muscle divides into medial and lateral parts, the twin
muscles. The tendons of flexor hallucis longus and flexor digitorum tendons of which are attached to the sides of the base of the proximal
longus run in the same plane as the muscles of the second layer (see phalanx of the great toe. The medial part blends with the tendon of
Fig. 84.20B); flexor hallucis longus and flexor digitorum longus are abductor hallucis, and the lateral with that of adductor hallucis, as they
described on pages 1410–1412. reach their terminations. | 1,972 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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is no phalangeal attachment for the transverse part of the muscle; fibres
that fail to reach the lateral sesamoid bone are attached with the oblique
Tendons of part.
flexor digitorum longus The transverse part of adductor hallucis is sometimes absent; part of
the muscle may be attached to the first metatarsal, constituting an
Tendon of opponens hallucis; a slip may also extend to the proximal phalanx of
flexor hallucis longus the second toe.
Tendons of Relations Adductor hallucis lies plantar to the metatarsal shafts and
flexor digitorum brevis interossei and the long and short toe flexors. The medial and lateral
plantar arteries and nerves are superficial, and flexor hallucis brevis is
proximal and medial.
Lumbricals Actions Adductor hallucis partly flexes the proximal phalanx of the
great toe, but also stabilizes the metatarsal heads.
Transverse
Adductor head Third dorsal
hallucis Oblique head interosseus Clinical anatomy Adductor hallucis is one of the deforming forces
Second and third in hallux valgus and needs to be released during a distal soft tissue
plantar interossei release when there is a fixed deformity.
Flexor hallucis brevis Fourth dorsal interosseus
Opponens digiti Flexor digiti minimi brevis
minimi Attachments Flexor digiti minimi brevis arises from the medial part
Abductor hallucis Flexor digiti
minimi brevis of the plantar surface of the base of the fifth metatarsal, and from the
Tendon of sheath of fibularis longus (see Figs 84.20B, 84.22 and 84.19A). It has
Abductor digiti minimi
flexor hallucis longus a distal tendon that inserts into the lateral side of the base of the proxi
Tendon of fibularis longus
Tendon of mal phalanx of the fifth toe; this tendon usually blends laterally with
flexor digitorum that of abductor digiti minimi. Occasionally, some of its deeper fibres
longus Flexor accessorius extend to the lateral part of the distal half of the fifth metatarsal, con
Tendon of tibialis posterior stituting what may be described as a distinct muscle: opponens digiti
Flexor retinaculum Long plantar ligament minimi.
Tendon of
flexor hallucis longus Abductor digiti minimi Relations The fifth metatarsal shaft lies on the deep surface of flexor
Plantar aponeurosis digiti minimi brevis, the interossei lie medially and abductor digiti
Abductor hallucis
minimi is lateral. The most lateral branch of the lateral plantar nerve
Flexor digitorum brevis lies superficially and just medial to flexor digiti minimi brevis.
Actions Flexor digiti minimi brevis flexes the metatarsophalangeal
joint of the fifth toe.
Fig. 84.22 Muscles of the sole of the foot, third layer. (With permission
from Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th Plantar muscles of the foot: fourth layer
ed, Elsevier, Urban & Fischer. Copyright 2013.)
The fourth layer of muscles of the foot consists of the plantar and dorsal
interossei and the tendons of tibialis posterior and fibularis longus
A sesamoid bone usually occurs in each tendon near its attachment. (tibialis posterior and fibularis longus are described in Ch. 83). The
Clinical problems with flexor hallucis brevis are usually related to the interossei resemble their counterparts in the hand except that, when
associated sesamoid bones. However, excision of both sesamoid bones describing adduction and abduction of the toes, the axis of reference is
leads to disruption of both tendons and a subsequent extension deform a longitudinal axis corresponding to the shaft of the second metatarsal
ity at the first metatarsophalangeal joint; such surgery is, therefore, not (unlike in the hand, where reference is made to the long axis of the
recommended. third metacarpal).
Accessory slips may arise proximally from the calcaneus or long
Dorsal interossei
plantar ligament. A tendinous slip may extend to the proximal phalanx
of the second toe. Attachments The dorsal interossei (Fig. 84.23A; see Fig. 84.19A) are
situated between the metatarsals. They consist of four bipennate
Relations Flexor hallucis brevis lies on the underside of the first muscles, each arising by two heads from the sides of the adjacent meta
metatarsal shaft; abductor hallucis lies medially. The medial digital tarsals. Their tendons are attached to the bases of the proximal phalanges
nerve to the great toe and the tendon of flexor hallucis longus pass to and to the dorsal digital expansions. The first inserts into the medial
the great toe on its plantar surface. The medial plantar nerve lies more side of the second toe; the other three pass to the lateral sides of the
superficially on its lateral side. second, third and fourth toes.
Actions Flexor hallucis brevis flexes the proximal phalanx of the great Relations Between the heads of each of the three lateral muscles, there
toe. is an angular space through which a perforating artery passes to the
dorsum of the foot. Between the heads of the first muscle, the corres
Testing The individual is asked to flex the first metatarsophalangeal ponding space transmits the terminal part of the dorsalis pedis artery
joint with the interphalangeal joint extended, thereby eliminating the to the sole (see Fig. 84.1).
action of flexor hallucis longus.
Actions Dorsal interossei abduct the toes relative to the longitudinal
Adductor hallucis
axis of the second metatarsal. They also flex the metatarsophalangeal
Attachments Adductor hallucis arises by oblique and transverse joints and extend the interphalangeal joints of the lateral four toes. The
heads (see Figs 84.20B, 84.22 and 84.19A). The oblique head arises great and fifth toes have their own abductors.
from the bases of the second, third and fourth metatarsals, and from
the fibrous sheath of the tendon of fibularis longus. The transverse head Clinical anatomy Denervation of the interossei leads to clawtoe
– a narrow, flat fasciculus – arises from the plantar metatarsophalangeal deformities. Development of clawed toes should alert the clinician to
ligaments of the third, fourth and fifth toes (sometimes only from the the possibility of a neuropathic process (e.g. Charcot–Marie–Tooth
third and fourth), and from the deep transverse metatarsal ligaments disease, tethered spinal cord).
between them. The oblique head has medial and lateral parts. The
medial part blends with the lateral part of flexor hallucis brevis and is Plantar interossei
attached to the lateral sesamoid bone of the great toe. The lateral part There are three plantar interossei (see Fig. 84.23B). They lie below,
joins the transverse head and is also attached to the lateral sesamoid rather than between, the metatarsals, and each is connected to only one
bone and directly to the base of the first phalanx of the great toe. There metatarsal. They are unipennate, unlike the dorsal interossei; they arise | 1,973 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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The muscle belly and tendon of extensor hallucis brevis serve as guides
A B to the location of the dorsalis pedis artery and deep fibular nerve. The
tendon of extensor hallucis brevis can be used as a local graft.
Vascular supply to the intrinsic muscles of the foot
Abductor hallucis is supplied by the medial malleolar network, medial
calcaneal branches of the lateral plantar artery (see Fig. 84.9), the
medial plantar artery (directly and via superficial and deep branches),
the first plantar metatarsal artery and perforators from the plantar art
erial arch. Flexor digitorum brevis is supplied by the lateral and medial
plantar arteries, the plantar metatarsal arteries and the plantar digital
arteries to the lateral four toes. Abductor digiti minimi is supplied by
the medial and lateral plantar arteries (see Figs 84.21, 84.25A), the
plantar digital artery to the lateral side of this muscle, branches from
1st the deep plantar arch, the fourth plantar metatarsal artery, and end
twigs from the arcuate and lateral tarsal arteries (see Fig. 84.9). Flexor
2nd 1st
2nd accessorius is supplied by the stem of the medial plantar artery (to the
3rd
3rd medial head), the lateral plantar artery and the deep plantar arch. The
4th lumbricals are supplied by the lateral plantar artery and deep plantar
arch and by four plantar metatarsal arteries (four distal perforating
arteries joined by three proximal perforating arteries). Their tendons are
supplied by twigs from the dorsal digital arteries (and their parent
dorsal metatarsal arteries) to the lateral four toes. Flexor hallucis brevis
is supplied by branches of the medial plantar artery, the first plantar
metatarsal artery, the lateral plantar artery and the deep plantar arch.
Fig. 84.23 The interossei of the left foot. A, The dorsal interossei viewed
Adductor hallucis is supplied by branches of the medial and lateral
from the dorsal aspect. B, The plantar interossei viewed from the plantar
plantar arteries, the deep plantar arch and the first to fourth plantar
aspect. The axis to which the movements of abduction and adduction are
metatarsal arteries. Flexor digiti minimi brevis is supplied by end twigs
referred is indicated.
of the arcuate and lateral tarsal arteries, and the lateral plantar artery
and its digital (plantar) branch to the lateral side of the fifth toe. Dorsal
interossei are supplied by the arcuate artery, lateral and medial tarsal
from the bases and medial sides of the third, fourth and fifth metatar
arteries, the first to fourth plantar arteries and the first to fourth dorsal
sals, and insert into the medial sides of the bases of the proximal
metatarsal arteries (receiving proximal and distal perforating arteries),
phalanges of the numerically corresponding toes, and into their dorsal
and by the dorsal digital arteries of the lateral four toes. Plantar inter
digital expansions.
ossei are supplied by the lateral plantar artery, the deep plantar arch,
Relations The plantar interossei lie plantar to the dorsal interossei the second to fourth plantar metatarsal arteries and the dorsal digital
and deep to the muscles of the third layer. arteries of the lateral three toes. Extensor digitorum brevis is supplied
by the anterior perforating branch of the fibular artery, the anterior
Actions Plantar interossei adduct the third, fourth and fifth toes, flex lateral malleolar artery, lateral tarsal arteries, dorsalis pedis artery,
the metatarsophalangeal joints and extend the interphalangeal joints. arcuate artery, the first, second and third dorsal metatarsal arteries,
proximal and distal perforating arteries, and the dorsal digital arteries
Clinical anatomy The clinical anatomy of the plantar interossei is to the medial four toes (including the great toe).
similar to that of the dorsal interossei.
Innervation of the intrinsic muscles of the foot Abductor
Extensor muscles of the foot hallucis is innervated by the medial plantar nerve, S1 and S2. Contrac
tion of the muscle confirms an intact medial plantar nerve when the
Extensor digitorum brevis and extensor integrity of this nerve is in question.
Flexor digitorum brevis is innervated by the medial plantar nerve,
hallucis brevis
S1 and S2. Abductor digiti minimi and flexor accessorius are innervated
Attachments Extensor digitorum brevis (see Fig. 84.2A) is a thin
by the lateral plantar nerve, S1, S2 and S3. The first lumbrical is supplied
muscle that arises from the distal part of the superolateral surface of
by the medial plantar nerve; the other lumbricals are supplied by the
the calcaneus in front of the shallow lateral groove for fibularis brevis,
deep branch of the lateral plantar nerve, S2 and S3. Flexor hallucis
from the interosseous talocalcaneal ligament, and from the deep surface
brevis is supplied by the medial plantar nerve, S1 and S2. Adductor
of the stem of the inferior extensor retinaculum. It slants distally and
hallucis is innervated by the deep branch of the lateral plantar nerve,
medially across the dorsum of the foot and ends in four tendons. The
S2 and S3. Flexor digiti minimi brevis is innervated by the superficial
medial part of the muscle is usually a more or less distinct slip, ending
branch of the lateral plantar nerve, S2 and S3. Dorsal interossei are
in a tendon that crosses the dorsalis pedis artery superficially to insert
supplied by the deep branch of the lateral plantar nerve (S2 and S3),
into the dorsal aspect of the base of the proximal phalanx of the great
except that of the fourth intermetatarsal space, which is supplied by the
toe; this slip is termed extensor hallucis brevis. The other three tendons
superficial branch of the lateral plantar nerve. Plantar interossei are
attach to the lateral sides of the tendons of extensor digitorum longus
supplied by the deep branch of the lateral plantar nerve (S2 and S3),
for the second, third and fourth toes.
except that of the fourth intermetatarsal space, which is supplied by the
The muscle is subject to much variation, e.g. accessory slips from the
superficial branch of the lateral plantar nerve. Extensor digitorum brevis
talus and navicular, an extra tendon to the fifth digit, or an absence of
is supplied by the lateral terminal branch of the deep fibular nerve, L5
one or more tendons. It may be connected to the adjacent dorsal
and S1.
interossei.
Relations The most medial tendon, that of extensor hallucis brevis, VASCULAR SUPPLY
courses dorsomedially and passes superficial to the dorsalis pedis artery
and the deep fibular nerve. The remaining three tendons pass obliquely ARTERIES
deep to the corresponding tendons of extensor digitorum longus.
Dorsalis pedis artery
Actions The muscle assists in extending the phalanges of the middle
three toes via the tendons of extensor digitorum longus; for the great
toe, it assists in extension of the metatarsophalangeal joint. The dorsalis pedis artery (see Fig. 84.1; Fig. 84.24) is usually the con
tinuation of the anterior tibial artery distal to the ankle. It passes to the
Clinical anatomy Laceration of extensor digitorum brevis leads to proximal end of the first intermetatarsal space, where it turns into
little in the way of functional impairment because the long extensors the sole between the heads of the first dorsal interosseous to complete
can compensate for the loss of the muscle. The proximal part of the the deep plantar arch, and provides the first plantar metatarsal artery.
muscle can be used as interposition material to prevent bone fusion The artery may be larger than normal, to compensate for a small
after resection of a calcaneonavicular bar (a common tarsal coalition). lateral plantar artery. It may be absent, in which event it is replaced by | 1,974 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Vascular supply
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First dorsal metatarsal artery The first dorsal metatarsal artery
(see Fig. 84.24) arises just before the dorsalis pedis artery enters the
sole. It runs distally on the first dorsal interosseous and divides at the
Anterior tibial artery
cleft between the first and second toes. One branch passes under
the tendon of extensor hallucis longus and supplies the medial side of
the great toe; the other bifurcates to supply the adjoining sides of the
great and second toes.
Anterior medial Perforating branch of Cutaneous vessels from the dorsalis pedis artery The dor
malleolar artery fibular artery salis pedis artery and its first dorsal metatarsal branch give rise to small
Anterior lateral direct cutaneous branches that supply the dorsal foot skin between the
malleolar artery extensor retinaculum and the first web space. This vessel provides the
Dorsalis pedis artery Lateral basis for a fasciocutaneous flap raised from this region, and which may
tarsal artery be used to cover superficial defects elsewhere.
Deep plantar arch
Medial tarsal arteries
Arcuate artery The deep plantar arch (Fig. 84.25B) is deeply situated, extending from
the fifth metatarsal base to the proximal end of the first intermetatarsal
space. Convex distally, it is plantar to the bases of the second to fourth
metatarsals and corresponding interossei, but dorsal to the oblique part
of adductor hallucis.
Branches
Dorsal metatarsal
arteries The deep plantar arch gives rise to three perforating and four plantar
metatarsal branches, and numerous branches that supply the skin,
fasciae and muscles in the sole. Three perforating branches ascend
through the proximal ends of the second to fourth intermetatarsal
spaces, between the heads of dorsal interossei, and anastomose with the
dorsal metatarsal arteries. Four plantar metatarsal arteries extend distally
between the metatarsals in contact with the interossei (Fig. 84.25). Each
divides into two plantar digital arteries, supplying the adjacent digital
aspects. Near its division, each plantar metatarsal artery sends a distal
Dorsal digital
perforating branch dorsally to join a dorsal metatarsal artery. The first
arteries
plantar metatarsal artery springs from the junction between the lateral
plantar and dorsalis pedis arteries, and sends a digital branch to the
Fig. 84.24 The dorsal arteries of the foot. medial side of the great toe. The lateral digital branch for the fifth toe
arises directly from the lateral plantar artery near the fifth metatarsal
base. Haemorrhage from the deep plantar arch is difficult to control
because of the depth of the vessel and its important close relations.
a large perforating branch of the fibular artery. It often diverges laterally
from its usual route. Surface anatomy
The lateral plantar artery begins between the heel and medial malleolus,
Relations
and crosses obliquely to a point 2.5 cm medial to the tuberosity of the
The dorsalis pedis artery crosses, successively, the talocrural articular
fifth metatarsal. With a slight distal convexity, it reaches the proximal
capsule, talus, navicular and intermediate cuneiform and their liga
end of the first intermetatarsal space.
ments; superficial to it are the skin, fasciae, inferior extensor retinacu
lum and, near its termination, extensor hallucis brevis. Medial to it is Posterior tibial artery
the tendon of extensor hallucis longus and lateral to it are the medial
tendon of extensor digitorum longus and medial terminal branch of
Before the posterior tibial artery divides into its two main terminal
the deep fibular nerve. The tendons are useful landmarks in the plan
branches, it gives off a communicating branch that runs posteriorly
ning of safe anatomical approaches in surgery of the ankle and foot.
across the tibia approximately 5 cm above its distal end, deep to flexor
Branches hallucis longus, and joins a communicating branch of the fibular artery;
calcaneal branches, which arise just proximal to the termination of the
The dorsalis pedis artery gives rise to the tarsal, arcuate and first dorsal
posterior tibial artery, pierce the flexor retinaculum and supply the skin
metatarsal arteries (see Figs 84.1, 84.9, 84.24).
and fat behind the calcaneal tendon; and the artery of the tarsal canal.
Tarsal arteries There are two tarsal arteries, lateral and medial (see The terminal branches of the posterior tibial artery are the medial and
lateral plantar arteries.
Fig. 84.24). They arise as the dorsalis pedis artery crosses the navicular.
The lateral runs laterally under extensor digitorum brevis; it supplies Branches
this muscle and the tarsal articulations, and anastomoses with branches Medial plantar artery The medial plantar artery is the smaller ter
of the arcuate, anterior lateral malleolar and lateral plantar arteries, and
minal branch of the posterior tibial artery (see Fig. 84.25). It arises
the perforating branch of the fibular artery. Two or three medial tarsal
midway between the medial malleolus and the medial calcaneal tuber
arteries ramify on the medial border of the foot and join the medial
cle, and passes distally along the medial side of the foot, with the medial
malleolar arterial network.
plantar nerve lateral to it. At first deep to abductor hallucis, it runs dis
tally between abductor hallucis and flexor digitorum brevis, supplying
Arcuate artery The arcuate artery (see Fig. 84.24) arises near the
both. Near the first metatarsal base, when its calibre is already dimin
medial cuneiform, passes laterally over the metatarsal bases, deep to
ished as a result of supplying numerous muscular branches, it is further
the tendons of the digital extensors, and anastomoses with the lateral
diminished by a superficial stem. It passes to the medial border of the
tarsal and plantar arteries. It supplies the second to fourth dorsal meta
great toe, where it anastomoses with a branch of the first plantar meta
tarsal arteries, running distally superficial to the corresponding dorsal
tarsal artery. Its superficial stem then trifurcates and supplies three super
interossei, and divides into two dorsal digital branches for the adjoining
ficial digital branches that accompany the digital branches of the medial
toes in the interdigital clefts. Proximally, these branches receive proxi
plantar nerve and join the first to third plantar metatarsal arteries.
mal perforating branches from the deep plantar arch. Distally, they are
joined by distal perforating branches from the plantar metatarsal arter Lateral plantar artery The lateral plantar artery is the larger termi
ies. The fourth dorsal metatarsal artery sends a branch to the lateral side nal branch of the posterior tibial artery (see Fig. 84.25). It passes distally
of the fifth toe. and laterally to the fifth metatarsal base; the lateral plantar nerve is
The frequency of the arcuate artery has been reported to range from medial. The plantar nerves lie between the plantar arteries. Turning
10% to 67%, depending on the precise definition of the artery (DiLan medially, with the deep branch of the nerve, it gains the interval between
dro et al 2001). the first and second metatarsal bases, and unites with the dorsalis pedis | 1,975 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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A B
Plantar digital arteries
Adductor hallucis, tendon of Plantar digital arteries
oblique head
Abductor hallucis
Tendon of flexor hallucis brevis,
lateral part Adductor hallucis,
transverse head
Dorsalis pedis artery, junction
with deep plantar arch Plantar metatarsal arteries
Digital branch to fifth toe
Flexor hallucis brevis
Deep plantar arch
Superficial digital branch
Medial plantar artery
Lateral plantar artery Medial plantar artery Adductor hallucis,
oblique head
Flexor digitorum brevis
Cutaneous branch
Lateral plantar artery
Abductor digiti minimi
Flexor accessorius
Abductor hallucis
Abductor digiti minimi
Calcaneal branches
Flexor digitorum brevis
Plantar aponeurosis Abductor hallucis
Fig. 84.25 The plantar arteries of the left foot. A, Superficial dissection. B, Deep dissection.
artery to complete the deep plantar arch. As it passes laterally, it is first The principal named superficial veins are the long and short saphen
between the calcaneus and abductor hallucis, then between flexor digi ous. Their numerous tributaries are mostly (but not wholly) unnamed;
torum brevis and flexor accessorius. Running distally to the fifth meta named vessels will be noted (see Fig. 78.9). As in the upper limb, the
tarsal base, it passes between flexor digitorum brevis and abductor digiti vessels will be described centripetally from peripheral to major drainage
minimi, and is covered by the plantar aponeurosis, superficial fascia channels.
and skin. Dorsal digital veins receive rami from the plantar digital veins in the
Muscular branches supply the adjoining muscles. Superficial clefts between the toes and then join to form dorsal metatarsal veins,
branches emerge along the intermuscular septum to supply the skin which are united across the proximal parts of the metatarsals in a dorsal
and subcutaneous tissue over the lateral part of the sole. Anastomotic venous arch. Proximal to this arch, an irregular dorsal venous network
branches run to the lateral border and join branches of the lateral tarsal receives tributaries from deep veins and is continuous proximally with
and arcuate arteries. Sometimes, a calcaneal branch pierces abductor a venous network in the leg. At each side of the foot, this network con
hallucis to supply the skin of the heel. Anastomosis between the medial nects with medial and lateral marginal veins, which are both formed
and lateral plantar arteries superficial to the flexor digitorum brevis is mainly by veins from more superficial parts of the sole. In the sole,
sometimes present and is termed the superficial plantar arch. superficial veins form a plantar cutaneous arch across the roots of the
toes and also drain into the medial and lateral marginal veins. Proximal
Perforator flaps in the ankle and foot region to the deep plantar arch there is a plantar cutaneous venous plexus,
especially dense in the fat of the heel. It connects with the plantar
cutaneous venous arch and other deep veins, but drains mainly into the
The arteries around the ankle and in the foot are the medial and lateral
marginal veins. The veins of the sole are an important part of the lower
calcaneal arteries, medial and lateral plantar arteries and the dorsalis
limb ‘venous pump’ system aiding propulsion of blood up the limb
pedis artery (see Fig. 78.7). In the foot, the two plantar arteries with
(Broderick et al 2008). Intermittent foot compression devices are avail
communicating arteries from the dorsalis pedis artery give rise to mul
able to enhance this flow and so reduce the risk of deep vein thrombosis
tiple small perfor ators. In the sole of the foot, the perforators emerge
during periods of increased risk, e.g. after surgery.
on either side of the plantar aponeurosis, and also pass through it, to
supply the skin. ‘Island flaps’ from these perforators may be advanced
to reconstruct small defects in the weightbearing area. The skin of the INNERVATION
sole of the foot is highly specialized and therefore, ideally, defects in
this region should be reconstructed using local skin.
Superficial fibular nerve
DEEP AND SUPERFICIAL VENOUS SYSTEMS The superficial fibular nerve is described on page 1416.
IN THE FOOT
Deep fibular nerve
Plantar digital veins arise from plexuses in the plantar regions of the
toes. They connect with dorsal digital veins to form four plantar meta The deep fibular nerve is described on page 1416.
tarsal veins, which run proximally in the intermetatarsal spaces and
Tibial nerve
connect via perforating veins with dorsal veins, then continue to form
the deep plantar venous arch, which is situated alongside the deep
plantar arterial arch. From this venous arch, medial and lateral plantar The branches of the tibial nerve that innervate structures in the ankle
veins run near the corresponding arteries and, after communicating and foot are articular, muscular, sural, medial calcaneal and medial and
with the long and short saphenous veins, form the posterior tibial veins lateral plantar nerves. The course and distribution of the tibial nerve in
behind the medial malleolus. the calf are described on page 1415. | 1,976 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Biomechanics of standing, walking and running
1447
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Medial calcaneal nerve Proper plantar digital arteries
The medial calcaneal nerve arises from the tibial nerve and perforates Proper plantar digital nerves
the flexor retinaculum to supply the skin of the heel and medial side
of the sole.
Medial plantar nerve
The medial plantar nerve is the larger terminal division of the tibial
nerve, and lies lateral to the medial plantar artery. From its origin under
the flexor retinaculum, it passes deep to abductor hallucis, then appears
between it and flexor digitorum brevis, gives off a medial proper digital Common plantar
nerve to the great toe, and divides near the metatarsal bases into three digital nerves
common plantar digital nerves (Fig. 84.26; see Fig. 84.21). Plantar metatarsal
Cutaneous branches pierce the plantar aponeurosis between abduc arteries
tor hallucis and flexor digitorum brevis to supply the skin of the sole
of the foot. Muscular branches supply abductor hallucis, flexor digit
orum brevis, flexor hallucis brevis and the first lumbrical. The first two
arise near the origin of the nerve and enter the deep surfaces of the Lateral plantar nerve,
muscles. The branch to flexor hallucis brevis is from the hallucal medial Medial plantar nerve superficial branch
digital nerve, and that to the first lumbrical from the first common
plantar digital nerve. Articular branches supply the joints of the tarsus
and metatarsus.
Three common plantar digital nerves pass between the slips of the
plantar aponeurosis, each dividing into two proper digital branches.
The first supplies adjacent sides of the great and second toes; the second Plantar aponeurosis
supplies adjacent sides of the second and third toes; and the third sup
plies adjacent sides of the third and fourth toes, and also connects with
the lateral plantar nerve. The first gives a branch to the first lumbrical.
Each proper digital nerve has cutaneous and articular branches: near
the distal phalanges, a dorsal branch supplies structures around the Flexor retinaculum
nail. Abductor hallucis, flexor hallucis brevis and the first lumbrical are
Medial calcaneal branches
all supplied by the medial plantar nerve. (tibial nerve)
Medial plantar nerve
Lateral plantar nerve
Posterior tibial artery
The lateral plantar nerve supplies the skin of the fifth toe, the lateral Lateral plantar nerve
half of the fourth toe, and most of the deep muscles of the foot (see
Fig. 84.21). It is located medial to the lateral plantar artery and courses
anteriorly towards the tubercle of the fifth metatarsal. Next, it passes Fig. 84.26 The plantar digital nerves. (With permission from Waschke J,
Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier,
between flexor digitorum brevis and flexor accessorius, and ends
Urban & Fischer. Copyright 2013.)
between flexor digiti minimi brevis and abductor digiti minimi by
dividing into superficial and deep branches. Before division, it supplies
flexor accessorius and abductor digiti minimi, and gives rise to small
branches that pierce the plantar aponeurosis to supply the skin of the nerve can be damaged in severe inversion injuries of the ankle, and the
lateral part of the sole (see Fig. 84.26). The superficial branch splits into deep fibular nerve is sometimes compressed by osteophytes in the
two common plantar digital nerves: the lateral supplies the lateral side region of the second tarsometatarsal joint. Sural nerve entrapment is
of the fifth toe, flexor digiti minimi brevis and the two interossei in the usually not due to compression by fascial elements. Entrapment of the
fourth intermetatarsal space; the medial connects with the third third common digital nerve as it passes deep to the intermetatarsal liga
common plantar digital branch of the medial plantar nerve and divides ment of the third (or less commonly the second) web space can result
into two to supply the adjoining sides of the fourth and fifth toes. The in a Morton’s neuroma, which is probably the most common form of
deep branch accompanies the lateral plantar artery deep to the flexor nerve entrapment in the foot.
tendons and adductor hallucis, and supplies the second to fourth lum
bricals, adductor hallucis and all the interossei (except those of the
fourth intermetatarsal space). Branches to the second and third lumbri ANATOMY OF THE TOENAILS
cals pass distally deep to the transverse head of adductor hallucis, and
travel around its distal border to reach them. See Video 84.1. NAIL STRUCTURE
Nerve entrapment syndromes in the foot A toenail consists of a nail plate and unit (Dykyj 1989; pages 151–152).
The toenail is commonly a site of several pathologies, including ony
All nerves of the foot can be affected by entrapment, leading classically chomycosis and onychocryptosis (Jules 1989, Eekhof et al 2012).
to a burning sensation in the distribution of that nerve. Tarsal tunnel
syndrome is much less common than carpal tunnel syndrome. The BIOMECHANICS OF STANDING, WALKING
flexor retinaculum may compress the tibial nerve or either of its
AND RUNNING
branches (medial and lateral plantar nerves); entrapment at this level
is most commonly due to a spaceoccupying lesion, e.g. a ganglion, or
to compression by either a leash of vessels or the deep fascia associated PLANES OF MOTION
with abductor hallucis. Compression of the first branch of the lateral
plantar nerve (Baxter’s nerve) by the deep fascia that covers abductor Much confusion surrounds the descriptive terms for movement in the
hallucis has been implicated as a possible cause of chronic heel pain foot and ankle. Plantar flexion and dorsiflexion refer to movement in
and of plantar fasciitis. (Plantar fasciitis, often caused by repetitive high the sagittal plane and occur principally, but not exclusively, at the ankle,
impact injury to the foot, may be associated with pain, especially over metatarsophalangeal and interphalangeal joints. Inversion is tilting of
the medial calcaneal process, which may be exacerbated by passive the plantar surface of the foot towards the midline, and eversion is
ankle or great toe flexion.) The medial plantar nerve can be compressed tilting away from the midline. This is motion in the coronal plane and
at the ‘knot of Henry’, which is the point where the tendon of flexor takes place principally in the talocalcaneal and transverse tarsal joints.
hallucis longus crosses deep to the tendon of flexor digitorum longus, Adduction is movement of the foot towards the midline in the trans
to reach its medial side in the sole of the foot. The superficial fibular verse plane; abduction is movement away from the midline. This | 1,977 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Ankle and foot
Patients with Morton’s neuroma usually present with a main com
plaint of metatarsalgia. While there is no pathognomonic clinical test,
diagnostic imaging coupled with clinical tests can provide convergent
validity to help with diagnosis (Owens et al 2011). Two commonly used
clinical tests are webspace tenderness and forefoot squeeze tests. The
webspace tenderness test is performed by placing the side of the thumb
into the third web space and pressing down. The forefoot squeeze test
is performed by squeezing the forefoot from side to side while concur
rently performing the webspace test.
1447.e1 | 1,978 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
AnklE And fooT
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movement occurs at the transverse tarsal joints and, to a limited degree, force fluctuations have to be larger at higher speeds, to give the same
the first tarsometatarsal and metatarsophalangeal joints. vertical movement in less time.
Supination describes a threedimensional movement and is a com
Development of walking
bination of adduction, inversion and plantar flexion. Pronation is the
opposite motion, i.e. a combination of abduction, eversion and dorsi The average child sits at 6 months, crawls at 9 months, walks with
flexion. Pronation and supination are usually better terms than eversion support at 12 months, and walks without support at 18 months. The
and inversion, as the latter rarely occur in isolation and the former characteristic early gait matures rapidly and is similar to that of the
describe the ‘compound’ motion that usually occurs. adult by 3 years. Some minor changes occur up to 7 years, which are
Active movements occur at the ankle, talocalcaneonavicular and sub largely a reflection of neurological development but are also related to
talar joints. Movements at the ankle joint are almost entirely restricted stature (Thomson & Volpe 2001). Early gait is jerky, unsteady and wide
to dorsiflexion and plantar flexion, but slight rotation may occur in based. Initial ground contact varies, and heel–toe, whole foot and toe–
plantar flexion. The ranges of movement at the talocalcaneonavicular heel are all possible. Generally, a plantar flexed posture is adopted,
and subtalar joints are greater; inversion and eversion mainly occur which contrasts with the adult pattern. In adults, heel strike is accom
here. panied by a straight knee, which then flexes. A child strikes the ground
with a flexed knee, which is then extended in response to weight
bearing, and a short time is spent in singleleg stance (Fig. 84.28).
STANDING Maturation is associated with diminution of base width and increase
in step length and velocity. The earliest changes are development of
heelstrike, knee flexion during stance, and reciprocal upper limb swing.
Humans are bipedal: we stand and walk with an erect trunk and knees
that are almost straight. Moreover, we are plantigrade, i.e. we set the
Running
whole length of the foot down on the ground, whereas most medium
to large mammals are digitigrade, i.e. they stand and walk on their toes,
and ungulates stand on hooves on the tips of their toes. In the sagittal Walking involves dualsupport phases, but in running each foot is on
plane, body weight acts along a line that passes a few centimetres ant the ground for 40% (jogging) to 27% (sprinting) of the stride, so there
erior to the tibiotalar joint, exerting a moment that must be balanced is an aerial phase – the ‘doublefloat’ phase – when neither foot is on
by the plantar flexor muscles. the ground. The faster the subject runs, the shorter the stance phase;
worldclass sprinters spend approximately 22% of the gait cycle in
stance. During each aerial phase, the body rises and then falls under
PROPULSION gravity, which means that its height and potential energy are maximal
in the middle of this phase and minimal at midstance, when, in
marked contrast to walking, the knee of the supporting leg bends. The
The contraction of tibialis posterior, gastrocnemius and soleus is the
changes in muscle belly lengths are relatively slight during running. The
chief factor responsible for propulsion in walking, running and
muscles are acting as tensioners of the tendons; indeed, most of the
jumping. The propulsive action of these calf muscles is enhanced by
change of length is produced by the stretch and recoil of the tendons.
arching of the foot and flexion of the toes. In walking, the weight on
It has been estimated that, of the kinetic and potential energy lost and
the foot is taken successively on the heel, lateral border and the first
regained in each stance phase, 35% is stored temporarily as elastic strain
metatarsophalangeal joint. The last part of the foot to leave the ground
energy in the calcaneal tendon, and 17% in the ligaments of the arch
is the anterior pillar of the medial longitudinal arch and the medial
of the foot. Together, these springs approximately halve the work
three toes. In the act of sprinting, the heel does not touch the ground,
required from the muscles.
but the point of takeoff is still the anterior pillar of the medial longi
The calcaneal tendon is the most important ‘spring’ in the leg. Most
tudinal arch. As the heel leaves the ground, the toes gradually extend.
runners strike the ground first with the heel, and the centre of pressure
Extension, of the great toe particularly, tightens the plantar aponeurosis
moves rapidly forwards to the distal heads of the metatarsals, where it
and thus heightens the arch. At the same time, flexor hallucis longus
remains for most of the stance phase.
and flexor digitorum longus elongate, which increases their subsequent
As in walking, the ground force acts more or less in line with the
contraction. The extrinsic and intrinsic toe flexors increase the force of
leg, so the body is decelerated and reaccelerated during each stance
takeoff by exerting force on the ground. The most important muscle
phase. The stance phase starts with deceleration and absorption of
in this respect is flexor hallucis longus, which is strongly assisted by the
energy. Power is generated after stance phase reversal as the limb pushes
intrinsic toe flexors. The lumbricals provide a balancing action to the
up with the knee extending and foot plantar flexed, and this continues
extrinsic flexors and prevent buckling of the toes during the toeoff
in the swing phase as the limb is accelerated forwards. Once the limb
phase of gait.
is ahead of the trunk, the final phase of swingphase absorption is initi
ated, during which the limb is decelerated.
Walking
The ground force acts upwards on the metatarsal heads, and the
calcaneal tendon pulls upwards on the calcaneus. The necessary balan
In walking, each foot is on the ground (stance phase) for approximately cing reaction occurs at the ankle, where the tibia presses downwards on
60% of the stride, and off the ground (swing phase) for approximately the talus. Together, these three forces flatten the longitudinal arch of
40% (Fig. 84.27). Thus, singlesupport phases (one foot on the ground) the foot, forcing the ankle 10 mm nearer to the ground than it would
alternate with doublesupport phases (two feet on the ground). The be if the foot were rigid. Mechanical tests on amputated feet have shown
knee is straight at heel strike and remains nearly straight (10–30°) for that the foot is a reasonably good spring, giving an energy return of
most of the stance phase of that leg, bending more only immediately nearly 80%. The plantar aponeurosis, long and short plantar ligaments
before toeoff. During the swing phase, the knee flexes to a maximum and the plantar calcaneonavicular ligament are all involved in the
of 60° at midswing. spring action; they are predominantly collagenous but presumably have
Stance phase starts with ‘heel strike’. With the foot still planted in elastic properties similar to those of tendon.
front of the body, ‘foot flat’ is reached, and becomes ‘midstance’ when
the body comes to be directly above the planted foot. The heel then
rises as the contralateral foot makes contact with the ground (the MOVEMENTS OF THE FOOT
‘double stance’ phase). The last event of stance is ‘toeoff’ when the
‘swing phase’ starts. Early in the stance phase, while it is ‘foot flat’ in With the foot on the ground, body weight causes some supination
front of the trunk, the foot pushes downwards and forwards on the (used here to imply uneven distribution of weight to the lateral side of
ground, decelerating the body as well as supporting it. Later, when the the foot) and flattening of the longitudinal arches; about onethird of
foot is behind the trunk, it pushes downwards and backwards, the weight borne by the forefoot is taken by the head of the first meta
reaccelerating the body (see Fig. 84.27). tarsal (McDonald and Tavener 1999). When a resting position becomes
The height of the centre of gravity, and therefore the potential energy active, as occurs on starting to walk, the foot is pronated (used here to
of the body, also fluctuates. This is inevitable if the knee is kept nearly imply uneven distribution of weight to the medial side of the foot) by
fully extended, making the hip move in a nearcircular arc about the muscular effort, and the first metatarsal is depressed (the second less
ankle of the supporting foot. The vertical component of the total force so), which accentuates the longitudinal arch to its maximum height
exerted by both feet on the ground in the doublesupport phase is (Hicks 1954). Similar changes can be imposed on a weightbearing foot
greater than body weight, giving the body an upward acceleration. The by active lateral rotation, which is transmitted through the tibia to the
vertical component of the ground force during the singlesupport phase talus and entails passive supination of the foot. Medial rotation has an
is less than body weight, giving the body a downward acceleration. The opposite effect. When the foot is grounded and immobile, muscles that | 1,979 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Biomechanics of standing, walking and running
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Phase of gait Stance phase Swing phase
Double Double
support Single-limb support support Single-limb support
(opposite side)
Pressure Heel strike Foot flat Mid-stance Heel-off Toe-off Mid-swing Heel strike
distribution
Hip
Joint angle
(extension = 0º) 45º 40º 30º 20º 5º 0º 20º 40º 50º 45º
Flexor mm
Extensor mm
Abductor mm
Adductor mm
Knee
Joint angle
(extension = 0º) 5º 10º 15º 10º 5º 10º 65º 55º 30º 5º
Flexor mm
Extensor mm
Ankle foot
Joint angle 5º 10º 0º 5º 5º 0º 5º 0º 5º 5º
(neutral = 0º) plantar- plantar- dorsi- dorsi- plantar- plantar- plantar-
Dorsiflexor mm
Plantar flexor mm
Inverter mm
Everter mm
Intrinsic mm
Ground reaction force
% Body
weight
100
Vertical force
15 Deceleration
0
Acceleration
–15
Sagittal force
% Gait cycle 0 10 20 30 40 50 60 70 80 90 100
Fig. 84.27 The events that occur during the different phases of a normal gait cycle. Depicted are: distribution of pressure on the plantar surface of the
foot; changes in the angles of hip, knee and ankle joints, together with activity in the corresponding muscle groups; and vertical and horizontal (sagittal
plane) components of the ground reaction force during stance phase. (Chart collated from various sources by Michael Gunther, Department of Human
Anatomy and Cell Biology, University of Liverpool.) | 1,980 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
AnklE And fooT
1450
9
noITCES
A
A
B
B
C
C
Fig. 84.29 The concept of the foot skeleton as a twisted plate that may
be untwisted (supination) or further twisted (pronation) during the
maintenance of a plantigrade stance in various positions of the foot.
A, The foot skeleton in supination, as in standing with the feet widely
separated. Note the marked medial tilting of the talus and, to a lesser
Fig. 84.28 Development of a mature gait. A, A 1-year-old. Note the flexed
degree, of the calcaneus and the depression of the medial longitudinal
elbows and lack of arm swing. The foot is plantar flexed at contact. B, A
arch. B, Relative pronation of the foot, as in standing with the feet close
3-year-old. Arm swing is now present, as is heel strike. C, A 6-year-old.
together. C, Supination of the foot when standing on an inclined surface;
There is now an adult-type gait. (With permission from Benson MKD,
if the position of the wedge had been reversed, the foot skeleton would,
Fixsen JA, MacNicol MF (eds) 2001 Development of a mature gait. In:
of course, approach maximal pronation. (Based on MacConaill MA 1945
Children’s Orthopaedics and Fractures, 2nd edn. Edinburgh: Churchill
The postural mechanism of the human foot. Proc Roy Irish Acad
Livingstone.)
50:265–278.)
move it when it is freely suspended may exert effects on the leg, e.g. the
dorsiflexors can then pull the leg forwards at the ankle joint. (though this varies with the position of the feet (Fig. 84.29), the devel
The foot has two major functions: to support the body in standing opment of associated soft tissues, and the nature of the surface). In any
and progression, and to lever it forwards and absorb shock in walking, activity, as soon as the heel rises, the toes are extended and muscular
running and jumping (Alexander 1992). To fulfil the first function, the structures (including the plantar aponeurosis) tighten up in the sole,
pedal platform must be able to spread the stresses of standing and accentuating the longitudinal arches. It has been suggested that tension
moving, and be pliable enough to accommodate walking or running diminishes in the deeper plantar ligaments in this phase.
over uneven and sloping surfaces. To fulfil the second function, the foot The sole is transversely concave, both in skeletal form and usually
must be transformable into a strong, adjustable lever in order to resist in external appearance, and serial transverse arches are most developed
inertia and powerful thrust; a segmented lever can best meet such inferior to the metatarsus and adjoining tarsus. Transmission of force
stresses if it is arched. occurs at the metatarsal heads, to some degree along the lateral border
In infants and young children, fatty connective tissue on the plantar of the foot, and through subjacent soft tissues.
aspect may give the foot a flat appearance and soft tissues modify its In standing, with only body weight to support, both the intrinsic
appearance to varying degrees at all ages. The thickness of the medial and extrinsic muscles appear to relax (Perry 2010). If the longitudinal
midfoot plantar fat pad ranges from 3.1 to 4.9 mm (RiddifordHarland arches are allowed to sink as a result of muscular relaxation, the plantar
et al 2007). However, the skeleton of the human foot is normally ligaments tie the bones into an arched form. The medial arch is more
arched, and the sole of the foot is usually visibly concave. These arches elevated when the feet are together than when they are apart, i.e. inver
vary individually in height, especially the longitudinal in its medial sion with supination increases as the feet are separated. This medial sag
part. Since they are dynamic, their heights also differ in different phases can be countered by voluntary contraction of muscles such as tibialis
of activity. anterior. Pronation and supination ensure that in standing, whatever
The medial longitudinal arch contains the calcaneus, talus, navicular, the position of the feet, a maximal weightbearing area is grounded,
cuneiform and medial three metatarsals. Its summit, at the superior from the metatarsal heads along the lateral border of the foot to the
talar articular surface, takes the full thrust from the tibia and passes it calcaneus. The twist of the ligamentous skeleton of the foot imparted
backwards to the calcaneus, and forwards through the navicular and by pronation (which is partly undone in supination) prompts the liken
cuneiforms to the metatarsals. When the foot is grounded, these forces ing of the foot to a twisted but resilient plate (see Fig. 84.29), where
are transmitted through the three metatarsal heads and calcaneus (espe adequate ground contact was ensured whatever the angle between the
cially its tuberosity). The medial arch is higher, and more mobile and foot and leg, and adaptable resilience was imparted in standing and
resilient than the lateral arch; its flattening progressively tightens the progression.
plantar calcaneonavicular ligament and plantar aponeurosis. The lateral
arch is adapted to transmit weight and thrust rather than to absorb such
Bonus e-book images and video
forces; the long plantar and plantar calcaneocuboid ligaments tighten
as it flattens.
The lateral arch makes contact with the ground more extensively
than the medial arch. As the foot flattens, an increasing fraction of load Fig. 84.19 Turbo spin-echo, T1-weighted magnetic resonance (MR)
traverses soft tissues, which are inferior to the entire arch. The whole images of the left ankle of a woman aged 26.
lateral border usually touches the ground, whereas the medial border
does not. However, the medial border is visibly concave, usually even Video 84.1 Ankle block: surface anatomy.
in standing, which explains the familiar outline of human footprints | 1,981 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
1451
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key references
KEY REFERENCES
BarclaySmith EB 1896 Astragalocalcaneonavicular joint. J Anat 30: Eekhof JA, Van Wijk B, Knuistingh Neven A et al 2012 Interventions for
390–412. ingrowing toenails. Cochrane Database Syst Rev 4:CD001541.
The first description of the astragalo-calcaneo-navicular joint and explained A meta-analysis of the efficacy of procedures used to treat ingrown toenails.
the importance of the joint complex in terms of hindfoot motion.
Jones FW 1949 Structure and Function as Seen in the Foot, 2nd ed. London:
Chen TM, Rozen WM, Pan WR et al 2009 The arterial anatomy of the Achil Baillière, Tindall & Cox.
les tendon: anatomical study and clinical implications. Clin Anat 22: Remains one of the classic texts on the foot.
377–85.
Kim PJ, Richey JM, Wissman LR et al 2010 The variability of the Achilles
A demonstration that the calcaneal tendon has three main territories of
tendon insertion: a cadaveric examination. J Foot Ankle Surg 49:
vascularity: a proximal section, mid-section and distal section. The
417–20.
mid-section had the poorest blood supply of all three territories.
A description of the variability in the terminal insertion site of the calcaneal
DiLandro AC, Lilja EC, Lepore FL et al 2001 The prevalence of the arcuate tendon that may be dependent on age.
artery: a cadaveric study of 72 feet. J Am Podiatr Med Assoc 91:
Wildenauer E 1950 Die Blutversorgung des Talus. Zeitschrift für Anatomie
300–5.
und Entwicklungsgeschichte 115:32–6.
A large cadaveric study in which the authors found that the arcuate artery
The first comprehensive account of talar blood supply and the identification
was present in only 16.7% of their sample of feet. They established that the
of the important artery of the tarsal canal.
lateral tarsal artery supplied dorsal metatarsal arteries 2–4 in 47.2% of
their sample, an arrangement that was more frequently found than the
commonly described arcuate artery. | 1,982 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
48
RETPAHC
Ankle and foot
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Achilles tendon. J Orthop Res 16:591–6. Eekhof JA, Van Wijk B, Knuistingh Neven A et al 2012 Interventions for
Alexander R McN 1992 The Human Machine. New York: Columbia Univer ingrowing toenails. Cochrane Database Syst Rev 4:CD001541.
sity Press. A meta-analysis of the efficacy of procedures used to treat ingrown toenails.
BarclaySmith EB 1896 Astragalocalcaneonavicular joint. J Anat 30: Gardner E, Gray DJ 1968 The innervation of the joints of the foot. Anat Rec
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A large cadaveric study in which the authors found that the arcuate artery physitis in children: an overuse syndrome. J Pediatr Orthop 7:34–8.
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lateral tarsal artery supplied dorsal metatarsal arteries 2–4 in 47.2% of ankle joint: anatomical variations. Foot Ankle Int 19:289–92.
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tion: a review. J Am Podiatr Med Assoc 101:176–86. Clin Anat 22:747–54. 1451.e1 | 1,983 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Myerson MS 1997 Adult acquired flatfoot deformity: treatment of dysfunc Scheyerer MJ, Helfet DL, Wirth S 2011 Diagnostics in suspicion of ankle
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Zantop T, Tillmann B, Petersen W 2003 Quantitative assessment of blood
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Muscles of the Extremities and the Trunk: Arterial Anastomotic Path
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COMMENTARY
9.1
Nerve biomechanics
Although assumed postures and movements place physical forces on tive tissue fibres contribute to stiffness (Borschel et al 2003). Endoneur
peripheral nerves, the biomechanical properties of these nerves permit ial fluid and the perineurial sheath that maintains the fluid compartment
continued electrical signalling in the face of reasonable physical also contribute to stiffness. When a nerve is elongated, it undergoes
demands. Consider the sciatic nerve in an individual moving from a transverse contraction (Walbeehm et al 2004): the reduction in cross
standing to a seated posture. Where it crosses the lateral rotators of the sectional area increases endoneurial compartment pressure contribut
femur, the nerve undergoes lengthening, its crosssectional shape ing to nerve stiffness (Millesi et al 1995). As one might predict, nerve
becomes elliptical and narrowed, and endoneurial fluid is forced proxi roots, which lack a perineurial sheath, demonstrate less stiffness than
mally and distally away from the site of shape change. The segment of a peripheral nerve (Beel et al 1986). External features, such as nerve
the sciatic nerve in the thigh glides proximally, converging towards the branching and entering/exiting blood vessels, resist elongation of a
flexing hip joint and diverging away from the flexing knee joint (Topp nerve in its nerve bed, and increase nerve stiffness measured in situ
and Boyd 2006). (Millesi et al 1995).
When a nerve bed is elongated across a moving joint, the nerve
undergoes longitudinal tension. The biomechanical response of that
nerve may be documented in a load–elongation curve, in which load
is measured in Newtons and length in millimetres (Haftek 1970). To
enable comparisons to be made between nerves, it is helpful to measure
their crosssectional areas and starting lengths, and translate the load–
elongation curves into stress–strain curves. Stress is defined as the inten
sity of force per unit crosssectional area, and may be reported in N/m2
or MPa (Pascal). Strain is defined as the ratio of change in length to the
o ler nig gi tn ha
.
l Tl hen reg et h d, isa tn ind
c
ti s
r
eo gf it oen
n
sr e ap reo r st ee ed
n
a s
in
a lop ae drc –e en lt oa ng ge
a
o tif
o
nth e
o
ro sr tig rein ssa –l
Stiffness
s tit ora ni n
o
fc u verv rye s
l
i( tF tli eg l.
o
9 a. d1 . o1 r) .
s
tI rn
e
st sh e
re
i sn ui lt ti sa l
i
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n
r ie fig cio ann
t
o ef
l
oth ne
g
ac tu iorv ne ,
o
a rp sp trl aic ina
.
Slope =
In the ‘linear behaviour’ region, there is a correlation between the
applied tensile load or stress and the elongation or strain. In the ‘plastic’
region of the curve, minimal tensile load or stress results in mechanical Toe region
failure and discontinuity of nerve structures.
Several structural features of peripheral nerves may be related to
segments of the stress–strain curve. Nerve in situ is under tension; the
transition between the ‘toe’ region and the ‘linear behaviour’ region of
the curve corresponds roughly with the in situ strain (Kwan et al 1992).
When severed, a peripheral nerve recoils approximately 10% of its
length. The elasticity observed in the stress–strain curve is due to struc
tures that make up visible, periodic light–dark bands that were initially
described by, and named after, Felix Fontana (Fontana 1781). These
bands vary in their angulation, width, spacing and periodicity; they
have long been assumed to be optical artefacts produced by the char
acteristic zigzag course of individual nerve fibres (i.e. axons, both
myelinated and unmyelinated) lying within the perineurial sheath. A
strong linear relationship between increasing nerve strain and decreas
ing band frequency and axonal undulations has been demonstrated
experimentally in rat sciatic nerve using Fourier analysis (Love et al
2013). In vivo microdissection studies coupled with computer model
ling suggest that the layers of perineurial cells are probably responsible
for the shortwavelength, largeamplitude bands and that wavy spiral
ling nerve fibres in the endoneurium are responsible for the long
wavelength, smallamplitude bands (Merolli et al 2012), the two
patterns merging to form the visible bands of Fontana. Interestingly, a
recent study of Trembler-J mice, a model of Charcot–Marie–Tooth
disease, suggested that the altered bands of Fontana in Trembler-J sciatic
nerve appear to be the result of unusually long, sinuous axons moving
Fig. 9.1.1 Typical load–elongation (A) and stress–strain curves (B) for a
out of phase (Power et al 2015). The zigzag, spiralling nerve fibres are
peripheral nerve. The transition between the toe region and the linear
thought to provide the elasticity evident in the ‘toe’ region of the stress–
region in the stress–strain curve (asterisk) has been shown to correspond
strain curve. Increasing strain in the ‘linear behaviour’ region of the
approximately with the strain in situ. The slope of the stress–strain curve
stress–strain curve causes the bands of Fontana to disappear (Pourmand
is called the modulus of elasticity and represents the stiffness of the
et al 1994).
nerve, as seen in the load–elongation curve. If the slope is steep, then the
Anatomical features have been studied to discern their contribution
nerve has more stiffness and is less compliant to elongation. If the slope
to the ‘linear behaviour’ region of the stress–strain curve. The slope of is less steep, then the nerve has less stiffness and is more compliant to
this region is termed Young’s modulus of elasticity, or in the case of the elongation. Once the nerve has reached ultimate strain, the structural
load–elongation curve, it indicates the stiffness of a nerve. A steep slope integrity of the nerve is overcome and the deformation is termed ‘plastic’
indicates that a nerve is stiff, and significant tensile force results in only or ‘permanent’. (From Topp KS, Boyd BS 2006 Structure and
modest change in length. The modulus of elasticity or stiffness of an biomechanics of peripheral nerves: nerve responses to physical stresses
e80 acellular nerve is similar to that of fresh nerve, indicating that connec and implications for physical therapist practice. Phys Ther 86:92–109.)
)N(
daoL
Plastic region
Ultimate load
12
1 680
Linear
behaviour
region
Ultimate
elongation
4
2
0
0 5 10 15 20
Elongation (mm)
Plastic region
Ultimate stress
12
1 680
Co inrr e ss itp uo sn td ras
i
nw *ith
Linear
behaviour
region
Modulus
of
elasticity
U slt ti rm aa inte
4 Slope
=
2 Toe region
0
0 5 10 15 20 25 30 35 40 45
Strain (%)
)aPM(
ssertS
Kimberly S Topp
A
B | 1,986 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Nerve biomechanics
e81
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YRATNEMMOC
In the ‘plastic’ region of the stress–strain curve, increasing longitu increasing stress along the ‘linear behaviour’ region of the stress–strain
dinal stress causes nonrecoverable elongation and structural integrity curve, long before the ultimate strain is reached.
is lost. The force per unit crosssectional area at the point of mechanical Nerve is best described as a viscoelastic tissue because its biomech
failure is termed ultimate stress and occurs at ultimate strain. At this anical properties are timedependent. In response to fixed tension,
point, a nerve behaves like a viscous material (Haftek 1970). Along the nerve demonstrates creep or elongation over time (Grewal et al 1996).
stress–strain curve, structures within the nerve become impaired in a Slow elongation allows for higher ultimate strain (Haftek 1970, Rydevik
hierarchical fashion. With increasing tensile load, there is first sliding et al 1990). When stretched to a fixed length, nerve exhibits stress
and loss of tenuous connections in the interface between the layer of relaxation or a reduction in tension over time (Wall et al 1991, Driscoll
inner perineurial cells and the sheath of outer perineurial cells and et al 2002).
associated epineurial tissues (Tillett et al 2004, Georgeu et al 2005). Returning to the example of the sciatic nerve, during movement from
With continued load, the core of nerve fibres and inner perineurial cell standing to seated, the nerve bed is elongated posterior to the hip as
layers is disrupted and function is impaired or lost; ultimately, the forward trunk motion causes flexion at the hip joint. The sciatic nerve
sheath of outer perineurial and epineurial tissues ruptures. Given that is exposed to tensile load or stress with resultant elongation or strain.
acellular nerve demonstrates significantly lower tensile strength and Adjusting to these forces, segments of the nerve converge towards the
ultimate strain than fresh nerve (Borschel et al 2003), the perineurial flexing hip joint, with minimal motion in distant segments (Topp and
cell layer should be appreciated for its ability to withstand stress. Boyd 2006). Endoneurial pressure resists transverse contraction. When
Although definitive anatomical studies are lacking, it is likely that the seated posture is assumed and maintained, the nerve undergoes
microscopic disruptions of perineurial cell–cell connections occur with stressrelaxation – until the next postural adjustment.
REFERENCES
Beel JA, Stodieck LS, Luttges MW 1986 Structural properties of spinal nerve Merolli A, Mingarelli L, Rochchi L 2012 A more detailed mechanism to
root: biomechanics. Exp Neurol 91:30–40. explain the ‘Bands of Fontana’ in peripheral nerves. Muscle Nerve 46:
Borschel GH, Kia KF, Kuzon WM et al 2003 Mechanical properties of acel 540–7.
lular peripheral nerve. J Surg Res 114:133–9. Millesi H, Zoch G, Reihsner R 1995 Mechanical properties of peripheral
Driscoll PJ, Glasby MA, Lawson GM 2002 An in vivo study of peripheral nerves. Clin Orthop Relat Res 314:76–83.
nerves in continuity: biomechanical and physiological responses to Pourmand R, Oches S, Jersild RA 1994 The relation of the beading of myeli
elongation. J Orthop Res 20:370–5. nated nerve fibers to the bands of Fontana. Neuroscience 61:373–80.
Fontana F 1781 Traité sur le vénin de la vipere, sur les poisons américains, Power BJ, O’Reilly G, Murphy R et al 2015 Normal nerve striations are
sur le lauriercerise et sur quelques autres poisons végetaux. On y a joint altered in the TremblerJ mouse, a model of Charcot–Marie–Tooth
des observations sur la structure primitive du corps animal. Différentes disease. Muscle Nerve 51:246–52.
experiences sur la reproduction des nerfs et la description d’un nouveau Rydevik BL, Kwan MK, Myers RR et al 1990 An in vitro mechanical and
canal de l’œil, vol. 2. Florence: Nyon L’Ainè. histological study of acute stretching on rabbit tibial nerve. J Orthop Res
Georgeu GA, Walbeehm ET, Tillett R et al 2005 Investigating the mechanical 8:694–701.
shearplane between core and sheath elements. Cell Tissue Res 320: Tillett RL, Afoke A, Hall SM et al 2004 Investigating mechanical behavior at
229–34. a core–sheath interface in peripheral nerve. J Peripheral Nerv Sys 9:
Grewal R, Xu J, Sotereanos DG et al 1996 Biomechanical properties of 255–62.
peripheral nerves. Hand Clin 12:195–204. Topp KS, Boyd BS 2006 Structure and biomechanics of peripheral nerves:
Haftek J 1970 Stretch injury of peripheral nerve. Acute effects of stretching nerve responses to physical stresses and implications for physical thera
on rabbit nerve. J Bone Joint Surg 52:354–65. pist practice. Phys Ther 86:92–109.
Kwan MK, Wall EJ, Massie J et al 1992 Strain, stress and stretch of peripheral Walbeehm ET, Afoke A, de Wit T et al 2004 Mechanical functioning of
nerve. Rabbit experiments in vitro and in vivo. Acta Orthop Scand 63: peripheral nerves: linkage with the ‘mushrooming’ effect. Cell Tissue Res
267–72. 316:115–21.
Love JM, Chuang TH, Lieber RL et al 2013 Nerve strain correlates with Wall EJ, Kwan MK, Rydevik BL et al 1991 Stress relaxation of a peripheral
structural changes quantified by Fourier analysis. Muscle Nerve 48: nerve. J Hand Surg Am 16:859–63.
433–5. | 1,987 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
COMMENTARY
Functional anatomy and biomechanics
9.2
of the pelvis
Andry Vleeming, Frank H Willard
This commentary focuses on the anatomy and biomechanics of the men and women (Vleeming et al 2012). The increase in mobility of the
pelvic girdle and, specifically, the sacroiliac joints. In bipeds, the pelvis pelvic ring seen in the post-pubescent female pelvis is functional in
serves as a basic platform with three large levers acting on it (the spine allowing passage for the child during labour. When the data are com-
and two lower limbs). Movement of the pelvic platform upon the hip bined from published studies employing RSA and appropriate placing
joints relative to the femur, such as flexion and extension (pelvic ante- of markers, the maximum sagittal rotation of the sacroiliac joint never
and retroversion), and rotation and abduction/adduction, strongly exceeds 3.6° and translation of the joint never exceeds 2 mm (Kibsgård
influences lumbar spinal movement. As well as this substantial exter- et al 2012). If these data are amalgamated with the observation that
nal pelvic motion, internal pelvic motion through the sacroiliac joint osteophytosis is rare in women, regardless of age (1.83% of females),
is essential for effectively transferring loads between the spine and and is not very common in men (12.27%; Dar et al 2008), it appears
lower limbs. It has been postulated that the sacroiliac joints act as that small sacroiliac joint movements are present, even at an advanced
important stress relievers in the ‘force–motion’ relationships between age (Vleeming et al 2012).
the trunk and lower limb (Vleeming et al 2007). These joints ensure
that the pelvic girdle is a flexible ring of bone that will not easily frac- Sacroiliac joint stability
ture under the great forces to which it might be subject, either from
trauma or from its many bipedal functions (Lovejoy 1988). Analysis of
To illustrate the importance of both myofascial and ligamentous stabil-
gait mechanics demonstrates that the sacroiliac joints provide suffi-
ity of the sacroiliac joint, the biomechanical principles of form and
cient flexibility for the intrapelvic forces to be transferred effectively to
force closure were introduced (Vleeming et al 1990a, Vleeming et al
and from the lumbar spine and lower extremities (Vleeming et al
1990b). Form closure refers to a theoretical stable situation in a joint
2007).
with closely fitting surfaces, where no extra forces are needed to main-
The sacroiliac joint is a highly specialized joint that lends stable (yet
tain the state of the system. With force closure (leading to joint com-
flexible) support to the upper body. Both the tightness of the well-
pression), both a lateral force and friction are needed to withstand
developed dorsal fibrous apparatus and the specific architecture of the
vertical load. The structural features that contribute to sacroiliac joint
sacroiliac joint result in limited mobility. Numerous researchers have
form closure are complementary ridges and grooves of the articular
tried to model sacroiliac joint function by studying its principal dis-
surfaces; dorsocranial ‘wedging’ of the sacrum into the ilia; a particular
placement characteristics. A common assumption of these studies is
high coefficient of friction in the sacroiliac joint (Vleeming et al 1990a,
that increased loading on the sacrum leads to tilting of the sacrum
Vleeming et al 1990b); and the integrity of the dorsal binding ligaments
ventrally (nutation), a process by which most dorsal sacroiliac joint
in particular, which are among the strongest in the body (Vleeming et al
ligaments are stretched and the dorsal aspects of the iliac bones are
1990a). Both form and force closure are necessary for balancing friction/
drawn together (Solonen 1957, Vleeming et al 1990a, Vleeming et al
compression in the sacroiliac joint. Force closure is the result of altered
1990b). Counternutation normally takes place in unloaded situations,
joint reaction forces by tensing ligaments, fasciae, muscles and ground
such as lying. Nutation implies a forward tilting of the sacrum relative
reaction forces (Vleeming et al 1990a, Vleeming et al 1990b). Force
to a posterior rotation of the ilia, and vice versa in counternutation.
closure ideally generates a perpendicular compressional reaction force
to the sacroiliac joint to overcome the forces of gravity (Vleeming et al
Sacroiliac joint movement
1990b).
Pelvic motion of males and females has been investigated by roentgen Biomechanical considerations and the active
stereophotogrammetric motion analysis (RSA). RSA is a technique for
straight leg raise (ASLR) test in pelvic girdle
measuring small movements and is regarded as the gold standard for
pain (PGP) patients
determining mobility in orthopaedics (Kibsgård et al 2012). Several
studies applied this technique to measure the mean sacroiliac joint
mobility, especially around the sagittal axis, in patients with pelvic PGP patients, who test positively on the functional ASLR test, show an
girdle pain (PGP; Sturesson 2007). The average mobility for men is inability to raise the leg while lying supine. This test can temporarily
about 40% less than for women. However, with age, there was no be normalized by manual anterior compression of the pelvis or the use
detectable decrease in total mobility in either gender (in patients up to of a pelvic belt. This suggests that increased unilateral motion of the
50 years old). In fact, there was a significant increase of mobility with sacroiliac joint could lead to impairment and failure to lift the leg
age for both moving from a ‘supine to sitting position’ and from ‘stand- (Mens et al 1999).
ing to lying prone with hyperextension’ position, particularly in women. Likewise, Sturesson (2007), using RSA, studied the effects of surgical
Likewise, gender differences of symphysial motion were analysed in a application of an anterior external fixation frame for severe PGP
group of 45 asymptomatic individuals. In men, the average frontal patients. This resulted in a mean reduction of movement of the sacro-
plane movement was 1.4 mm, and in nulliparous women 1.6 mm. iliac joint around the helical axis of 59% and around the X-axis of 74%.
However, in multiparous women, motion increased to 3.1 mm (Garras In addition, the ASLR test and other evidence-based PGP tests were
et al 2008). normalized (Vleeming et al 2008). When the frame was tightened, a
The increased sacroiliac joint mobility in females compared to males nutation movement of the sacrum was noticed (Sturesson 2007).
has possible anatomical correlates. The curvature of the sacroiliac joint This and other studies mentioned in this commentary imply that
surfaces is usually less pronounced in women to allow for greater ‘too much movement’ of the sacroiliac joint could be a significant factor
mobility (Vleeming et al 1990a). Also, the pubic angle differs between in the onset of PGP (Vleeming et al 2008).
REFERENCES
Dar G, Khamis S, Peleg S et al 2008 Sacroiliac joint fusion and the Garras DN, Carothers JT, Olson SA 2008 Single-leg-stance (flamingo) radio-
implications for manual therapy diagnosis and treatment. Man Ther 13: graphs to assess pelvic instability: how much motion is normal? J Bone
e82 155–8. Joint Surg Am 90:2114–18. | 1,988 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Functional anatomy and biomechanics of the pelvis
e83
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YRATNEMMOC
Kibsgård TJ, Røise O, Stuge B et al 2012 Precision and accuracy measurement Vleeming A, Volkers AC, Snijders CJ et al 1990b Relation between form and
of radiostereometric analysis applied to movement of the sacroiliac function in the sacroiliac joint. Part II: Biomechanical aspects. Spine
joint. Clin Orthop Relat Res 470:3187–94. 15:133–6.
Lovejoy CO 1988 Evolution of human walking. Sci Am 25:118–25A. Vleeming A, Mooney V, Stoeckart R (eds) 2007 Movement, Stability and
Mens JM, Vleeming A, Snijders CJ et al 1999 The active straight leg raising Lumbopelvic Pain: Integration of Research and Therapy, 2nd ed. Edin-
test and mobility of the pelvic joints. Eur Spine J 8:468–73. burgh: Elsevier, Churchill Livingstone, p. 658.
Solonen KA 1957 The sacroiliac joint in the light of anatomical, roentgeno- Vleeming A, Albert HB, Ostgaard HC et al 2008 European guidelines for the
logical and clinical studies. Acta Orthop Scand 27:1–127. diagnosis and treatment of pelvic girdle pain. Eur Spine J 17:794–819.
Sturesson B 2007 Movement of the sacroiliac joint with special reference Vleeming A, Schuenke MD, Masi AT et al 2012 The sacroiliac joint: an over-
to the effect of load. In: Vleeming A, Mooney V, Stoeckart R (eds) view of its anatomy, function and potential clinical implications. J Anat
Movement, Stability and Lumbopelvic Pain: Integration of Research 221:537–67.
and Therapy, 2nd ed. Edinburgh: Elsevier, Churchill Livingstone,
pp. 343–52.
Vleeming A, Stoeckart R, Volkers AC et al 1990a Relation between form and
function in the sacroiliac joint. Part I: Clinical anatomical aspects. Spine
15:130–2. | 1,989 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
COMMENTARY
9.3
Articularis genus
Stephanie J Woodley
Articularis genus, sometimes referred to as the ‘articular muscle of the capsule (DiDio et al 1967, Kimura and Takahashi 1987, Woodley et al
knee’ (Puig et al 1996), is a small muscle located deep to vastus inter 2012, Reider et al 1981). The muscle may be triangular, rectangular or
medius on the anterior aspect of the thigh (Fig. 9.3.1). Due to its distal trapezoid in shape (DiDio et al 1967, Toscano et al 2004, DiDio et al
capsular insertions, it is morphologically similar to the subanconeus 1969). There is considerable variation in the reported mean muscle
muscle (articularis cubiti) of the elbow joint, although subanconeus is length (between 6.2 and 14 cm in adults; Ahmad 1975, DiDio et al
considered to represent the deep fibres of the medial head of triceps 1967, Toscano et al 2004, Woodley et al 2012), as well as the number
brachii (rather than being a separate entity) and its function is likely to of constituent bundles, which typically ranges from 1 to 7 (Puig et al
differ from that of articularis genus (Tubbs et al 2006). From an evolu 1996, Ahmad 1975, DiDio et al 1967, Toscano et al 2004, Sakuma et al
tionary perspective, fibres corresponding to articularis genus have been 2014) but sometimes exceeds 10 (DiDio et al 1969, Reider et al 1981;
described in early tetrapods (Diogo and Molnar 2014) and it is compar see Table 9.3.1). The number of bundles may be underestimated when
able to the subcrureus muscle of primates including apes, gorillas and viewed using magnetic resonance imaging (Puig et al 1996, Woodley
lemurs (Murie and Mivart 1872, Hepburn 1892). A distinct, yet small, et al 2012), possibly because of the reasonably compact nature of this
articularis genus is also found in domestic animals such as the dog, cat muscle. Recent dissection evidence demonstrates that 6 of 11 different
and goat (Getty 1975, Kincaid et al 1996, Glenn and Samojla 2002, muscle bundles, organized in superficial, intermediate and deep layers,
Evans 2013). are consistently present (Woodley et al 2012; Fig. 9.3.4). The superficial
While articularis genus has been of interest to anatomists for over layer usually comprises a large central bundle bordered by lateral and
two centuries (refer to DiDio et al (1967) for a historical account), medial bundles; fascicles in some of these bundles may insert into the
controversy still surrounds many aspects of its architecture. Discrepan bursa through an intermediary thin areolar membrane (see Fig. 9.3.4).
cies in the literature are most likely to be the result of differences in A central bundle forms the intermediate layer, and two bundles (medial
study methodologies, particularly with respect to the type and scope of and lateral) make up the deepest part of articularis genus, and may be
data collected and/or in definitions of the muscle and its components. accompanied by a third, central bundle (Sakuma et al 2014). Bundle
To date, most studies of articularis genus have been dissectionbased;
there are only three studies in which modern imaging techniques have
been used to investigate morphology (Puig et al 1996, Roth et al 2004,
Woodley et al 2012) (Table 9.3.1). Ant
Articularis genus consists of staggered layers of bundles (Puig et al Sup Inf
1996, Kimura and Takahashi 1987, Woodley et al 2012) that arise from Post
the distal third of the anterior, medial and lateral surfaces of the femur
(Ahmad 1975, DiDio et al 1967, Woodley et al 2012, DiDio et al 1969)
(Fig. 9.3.2), with a broad attachment to the proximal and/or posterior
margins of the suprapatellar bursa (Puig et al 1996, Ahmad 1975,
Kimura and Takahashi 1987, Toscano et al 2004, Woodley et al 2012,
S VI I D
Sakuma et al 2014) (Fig. 9.3.3) and specific regions of the articular
Fig. 9.3.2 A medial view of the bundles of articularis genus arranged into
superficial (S), intermediate (I) and deep (D) layers, inserting into the
suprapatellar bursa. Note that some superficial fascicles insert into the
Fig. 9.3.1 An anterior
deep surface of the vastus intermedius (VI) tendon.
view of the thigh
showing articularis
genus (AG) deep to
the reflected vastus
intermedius (VI) muscle.
VI Other abbreviations: AG
N, nerve branch to
VI
articularis genus from
the femoral nerve;
AG P, proximal border *
N of bisected patella;
VM, vastus medialis;
* midpoint of
suprapatellar bursa.
*
VM
P
Fig. 9.3.3 A sagittal proton density MRI scan of the knee from a
Sup
Med Lat 23-year-old female. The distal portion of articularis genus (AG), deep to
e84 Inf vastus intermedius (VI), is seen inserting into the suprapatellar bursa (*). | 1,990 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
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Table 9.3.1 Summary of data relating to the morphology of articularis genus
Study Study characteristics (type, General muscle morphology; origin and insertion Architectural parameters
specimen number and sex)
DiDio et al Dissection following injection of Separated from VI by connective tissue and fat Muscle length: mean 8 cm (range 3–13 cm)
(1967) gelatine Shape: rectangular 56%; trapezoid 27%; inverted trapezoid 17% Most proximal point of insertion: mean 10.5 cm (range 8–16 cm)a
n = 156 adults O: distal femur, anterior, medial and lateral Bundles: n = 1–6, most commonly 1 or 2 (78%); same number bilaterally in
104 male, 52 female I: articular capsule at the level of the suprapatellar bursa, mostly 60% of individuals
proximal, centre. Also to medial and lateral aspects, Maximum bundle width: mean 0.9 cm (range 0.1–4.0 cm)
occasionally anterior and posterior
DiDio et al Dissection Shape: triangular 44%; lambdoidal 27%; rectangular 24%; Muscle length (fetal, n = 14): mean 4.4 cm; range 1.2–5.4 cm
(1969) n = 66 (fetuses, newborn, adults) unclassified 5% Maximum muscle width (fetal, n = 14): mean 0.9 cm; range 0.2–2.0 cm
Histology O: distal third of femur, anterior (92.4%) and lateral or medial Bundles: n = 1, 66.7%; n = 2 divergent but not separate, 27.3%; n = 2, 1.5%;
n = 16 fetuses aspects (30.3%) unaccounted, 4.5%. Same number bilaterally in 82% of individuals
29–34 weeks I: articular capsule at the level of the suprapatellar bursa
Ahmad Dissection Margins demarcated by fat and connective tissue Muscle length: mean 9 cm
(1975) n = 20 O: distal femur, usually anterior, occasionally medial and lateral Fibre direction: mostly vertical, some inferomedial or inferolateral
aspects Bundles: n = 1–2 most common, sometimes 3–4
I: suprapatellar bursa, proximal border. Central, medial or lateral, Innervation: branch of nerve to VI
occasionally posterior or anterior aspects
Reider et al Dissection Flat and wispy without distinct investing fascia Muscle width: range 1.5–3 cm
(1981) n = 24 from 48 adults O: anterior aspect supracondylar portion of femur
26 male, 22 femaleb I: joint capsule at suprapatellar bursa
40–90 years
Kimura and Dissection Superficial and deep layers, separated by fat Most proximal point of insertionc: range 14.9–16.5 cm (superficial layer);
Takahashi n = 44 adults Superficial layer: derived from lower muscle bundles of VI 10.2–11.9 cm (deep layer)
(1987) 36 male, 8 femaleb I: suprapatellar bursa, posterior aspect, spreading medially and Bundles: n = >10 bundles
laterally. Posterior aspect of capsule Deep layer: mean 3.4 bundles; range 1–7, usually 2
Superficial layer: 2 bundles
Bundle length: range 5.2–6.6 cm (superficial layer); 3.5–5.0 cm (deep layer)
Innervation: femoral nerve, one branch derived from the common branch to
VI and VL, the other from that to VM and VI (superficial layer). Deep layer
supplied by common branch to VM and VI
Puig et al MRI (prospective and retrospective) O: anterior surface of femur Maximal muscle transverse aread: mean 1.2 ± 0.3 cm2; range 0.8–2.0 cm2
(1996) n = 40 from 34 patients I: suprapatellar bursa, proximal surface, medial and lateral aspect Highest point of insertiona: mean 6.4 ± 0.5 cm; range 3.5–9.0 cm
19 male, 15 femaleb of posterior surface Bundles: n = mean 2.4 ± 0.7; range 1–4
16–56 years Most proximal bundle: mean length 4.7 ± 0.4 cm; range 3.1–6.6 cm; mean
anglee 11.4 ± 1.3°; range 6.0–17.5°; mean transverse diameter (at origin)
0.9 ± 0.08 cm; range 0.6–1.3 cm
Most distal bundle: mean length 2.8 ± 0.4 cm; range 0.9–3.5 cm; mean
anglee 12.4 ± 2.5°; range 5.0–20.0°
Roth et al MRI (retrospective) Anteroposterior muscle thickness: range 0.1–0.8 cm
(2004) 92 knees from 84 patients
42 male, 42 female
20–76 years
Toscano et al Dissection Separated from VI by fat of variable thickness Muscle length: mean 6.2 cm; range 3.8–8.5 cm
(2004) n = 65 from 44 adults Shape: trapezoid 40%; rectangular 33%; triangular and irregular Most distal point of insertionf: mean 3.0 cm; range 2.0–4.1 cm
36 male, 8 femaleb 27% Bundles: n = range 2–7, 4 most frequent (33%)
O: distal third of femur, usually anterior (43%) Bundle orientation: mostly vertical, some oblique
I: suprapatellar bursa, often anterior (57%)
Woodley et al MRI and dissection Distinct from VI Muscle lengthh: mean 13.9 ± 1.1 cm; 12.3–17.4 cm
(2012)g n = 18 adults Staggered arrangement comprised of three layers (superficial, Muscle PCSA: mean 1.5 ± 0.7 cm2; range 0.5–3.3 cm2
8 male, 10 female intermediate and deep)
71–97 years O: distal 32% of femur (range 29–42 cm), anterior, anterolateral Fascicle length: mean 5.9 ± 1.0 cm
Histology or anteromedial surfaces Bundles: n = mean 7 ± 1.8; range 4–10, same number bilaterally in 44% of
n = 4 adults I: proximal and/or posterior wall of suprapatellar bursa, directly or individuals; MRI mean 3.8 ± 0.8; range 2–5, significantly less than
4 male via a thin areolar membrane; deep surface of distal tendon of dissection (p <0.0001)
68–80 years VI (superficial bundles); knee joint capsule, posterior or Bundle orientation: mostly vertical (1–5°) except three bundles (two of
posteromedial surface (one intermediate and both deep which were in deep layer; mean range 11–15°)
bundles) Most proximal point of insertiona: mean 12.4 ± 2.9 cm; range 7.2–17.4 cm
Most distal point of insertiona: mean 3.3 ± 2.8 cm; range 0–10.4 cm
Fibre type: inconclusive due to variation
Sakuma et al Dissection Superficial and deep layers, separated by fat in some All measurements relate to deep layer
(2014) n = 40 from 22 adults Deep layer comprised of three bundles (medial, central, lateral) Bundles: n = 2.7 ± 0.5
13 male, 9 female O: anterior aspect of femur Bundle length: mean 5.4 ± 1.3 cm; medial bundle longer than lateral
77–98 years I: Junction of suprapatellar bursa and joint cavity proper (deep (p < 0.05)
fibres) Bundle areai: 5.5 ± 2.6 cm2; medial bundle larger than lateral (p < 0.05)
and central (p < 0.05) bundles
aProximal border or apex of patella used as landmark. bRepresents number of cadavers/participants, not specimens. cRelative to the distal end of the medial femoral condyle, unclear if data from one specimen or all specimens.
dIn this study ‘±’ refers to SEM. eAngle recorded between anterior surface of femur and posterior surface of muscle bundle. fRelative to superior edge of trochlea. gAll data relate to dissection measures unless stated. hIn this
study ‘±’ refers to standard deviation. iCalculated by multiplying bundle length by width.
Abbreviations: I, insertion; MRI, magnetic resonance imaging; n, number; O, origin; PCSA, physiological cross-sectional area; VI, vastus intermedius; VL, vastus lateralis; VM, vastus medialis.
orientation is predominantly longitudinal, although the deepest two it is possible that this arrangement enables the longer, superficial fasci
peripheral bundles may be oriented obliquely (Puig et al 1996, cles to accommodate changes in muscle length (Woodley et al 2012),
Ahmad 1975, Toscano et al 2004, Woodley et al 2012). Symmetry of particularly during knee flexion, where it is postulated that the length
bundle arrangement in the right and left limbs of individuals appears of each bundle of articularis genus elongates twofold at the endrange
variable (40–82%; DiDio et al 1967, Woodley et al 2012, DiDio et al of movement (Kimura and Takahashi 1987).
1969, Sakuma et al 2014). There has been longstanding debate as to whether articularis genus
Articularis genus is diminutive: its mean physiological crosssectional is a deep bundle of quadriceps femoris or an independent muscle
area of 1.5 ± 0.7 cm2 (cadaver specimens; Woodley et al 2012) indicates (DiDio et al 1967). While it is true that articularis genus and vastus
that it is capable of generating only a small amount of force. Fascicle intermedius share an innervation from branches of the femoral nerve
length (mean 5.9 ± 1.0 cm; Woodley et al 2012) is likely to be influ (Ahmad 1975, Kimura and Takahashi 1987; see Fig. 9.3.1), other ana
enced by bundle location (Puig et al 1996, Kimura and Takahashi 1987, tomical data tend to favour the view that articularis genus is an inde
Woodley et al 2012). The deepest, most distal layer of articularis genus pendent muscle. First, although a small percentage of superficial
contains the shortest fascicles, and the superficial, proximal bundles fascicles in the superficial bundles of articularis genus may insert into
contain the longest (Woodley et al 2012; see Fig. 9.3.4). Functionally, the deep layer of the distal tendon of vastus intermedius (see Fig. 9.3.2), | 1,991 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
ARTiCulARis gENus
e86
9
NOiTCEs
the bulk of articularis genus appears distinct from the overlying quad
riceps (Kimura and Takahashi 1987, Woodley et al 2012). Second, the
two muscles may be delineated by a distinct fascial layer of variable
composition and thickness (Ahmad 1975, DiDio et al 1967, Toscano
et al 2004), although this feature is inconsistent (Kimura and Takahashi
1987, Woodley et al 2012, Toscano et al 2004). The fibre type profiles,
albeit limited to four cadaver specimens, appear to differ between artic
ularis genus and vastus intermedius (Woodley et al 2012). Perhaps the
most reliable method of defining articularis genus is by reference to its
A
discrete distal insertion sites into the suprapatellar bursa and/or joint
capsule (Kimura and Takahashi 1987, Woodley et al 2012). Articularis
P VI * AM S genus may hypertrophy (Puig et al 1996) or atrophy (Toscano et al
* S 2004) in parallel with quadriceps femoris, but the significance of these
adaptations is unknown.
When contemplating function, the architectural arrangement of
articularis genus is paramount because direct evidence regarding its
action is limited to a single study (Ahmad 1975). Ahmad observed
elevation of the knee joint capsule and synovial membrane on stimulat
ing a branch of the femoral nerve innervating articularis genus in three
patients undergoing surgical amputation. This finding is consistent with
previous hypotheses, suggesting that articularis genus is responsible for
retracting the suprapatellar bursa or knee joint capsule proximally
B (Ahmad 1975, DiDio et al 1967, Kimura and Takahashi 1987, Roth
et al 2004, Toscano et al 2004), potentially preventing interposition of
these structures between the patella and femur during extension of the
S I S knee joint (Ahmad 1975, DiDio et al 1967). Functional implications
may be elucidated from comparison with the dog stifle (knee) joint,
P * D
where articularis genus usually consists of two thin bundles (medial
and lateral) forming an ‘invertedV’ shaped muscle (Kincaid et al 1996),
approximately 2 mm wide (Evans 2013). This morphology, together
with the distribution of muscle spindles, which are located both in the
vicinity of the musclecapsule interface and isolated within the capsular
connective tissue, suggest that in addition to tensioning the suprapatel
lar bursa (Kincaid et al 1996, Evans 2013), articularis genus may have
an important proprioceptive role (Kincaid et al 1996).
A detailed knowledge of the morphology of articularis genus is rel
C evant to understanding normal function of the knee joint as well as its
Inf Sup
role in possible dysfunction; for example, the possible protective role
that articularis genus may have in counteracting impingement of cap
D sular tissues (Ahmad 1975, DiDio et al 1967) might be appropriate to
Fig. 9.3.4 The three layers of articularis genus. A, The superficial (S) layer, consider in some individuals who present with undifferentiated ant
where some fascicles insert into the suprapatellar bursa via an areolar erior knee pain (Woodley et al 2012). It is perhaps surprising that this
membrane (AM). Note the presence of a complete superior plica muscle has not been afforded more attention; given its complexity and
(arrowheads), positioned between the knee joint cavity and the variability, there is scope for further examination of its detailed anatomy
suprapatellar bursa. B, The intermediate (I) layer beneath the reflected and function, particularly in healthy volunteers. Techniques such as
superficial (S) bundles. C, Two deep (D) bundles, positioned laterally and dynamic magnetic resonance imaging and electromyography may be
medially. Other abbreviations: P, proximal pole of bisected patella; VI, useful adjuncts to morphological investigations, and assist in contribut
vastus intermedius tendon; * proximal border of the midpoint of the ing to a better understanding of the functional and clinical relevance
suprapatellar bursa.
of this interesting muscle.
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