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pudendal nerve also may supply pubococcygeus from its lateral surface ated upper portion of the attachment of levator ani. It is connected to
through its inferior rectal and perineal branches. the posterior part of the arcuate line of the ilium and is continuous
with iliac fascia. Anterior to this, as it follows the line of origin of obtu-
Actions Pubococcygeus and puborectalis pull the pelvic and perineal rator internus, it is gradually separated from the attachment of the iliac
structures ventrally and cranially, occluding the levator hiatus. In the fascia, and a portion of the periosteum of the ilium and pubis spans
female, this action occludes the vaginal canal and prevents prolapse of between them. It arches below the obturator vessels and nerve, investing
the pelvic organs through the urogenital hiatus. The constant baseline the obturator canal, and is attached anteriorly to the back of the pubis.
activity of the levator muscles is similar to that of the anal sphincter, Behind the obturator canal, the fascia is markedly aponeurotic and gives
modulated to adjust to the loads placed on them. The action of pubo- a firm attachment to the iliococcygeal portion of levator ani, usually
rectalis and pubococcygeus also reinforces the external anal sphincter called the tendinous arch of levator ani (arcus tendineus musculi leva-
and helps to create the anorectal angle. Iliococcygeus and, to a lesser toris ani) (see Figs 73.3, 73.14, 73.15). Above the attachment of levator
extent, the less muscular ischiococcygeus form a relatively horizontal ani, the fascia is thin and is effectively composed only of the epimysium
diaphragm, especially in the dorsal half of the pelvis, that assists pubo- of the muscle and overlying connective tissue; posteriorly, it forms part
rectalis in achieving anorectal and urinary continence. of the lateral wall of the ischio-anal fossa in the perineum, and anteri-
Levator ani must relax appropriately to permit expulsion of urine orly, it merges with the fasciae of the muscles of the deep perineal space,
and, particularly, faeces; it contracts with the abdominal muscles and which is continuous with the ischio-anal fossa. The obturator fascia is
the abdominothoracic diaphragm to raise intra-abdominal pressure. It continuous with the pelvic periosteum and, thus, the fascia over
forms much of the muscular pelvic diaphragm, which supports the piriformis.
pelvic viscera. Like the abdominothoracic diaphragm, but unlike the
abdominal muscles, levator ani is also active in the inspiratory phase fascia over piriformis
of quiet respiration. In the pregnant female, the shape of the pelvic floor The fascia over the inner aspect of piriformis is very thin, and fuses with
may help to direct the fetal head into the anteroposterior diameter of the periosteum on the front of the sacrum at the margins of the anterior
the pelvic outlet. sacral foramina. It ensheathes the anterior primary rami of the sacral
nerves that emerge from these foramina; the nerves are often described
Pelvic fasciae as lying behind the fascia. The internal iliac vessels lie in front of
the fascia over piriformis; their branches draw out sheaths of the fascia
The pelvic fasciae may be conveniently divided into the parietal pelvic and extraperitoneal tissue into the gluteal region, above and below
fascia, which forms the coverings of the pelvic muscles, and the visceral piriformis.
pelvic fascia, which forms the coverings of the pelvic organs and their
fascia over levator ani (pelvic diaphragm)
neurovascular supply (Fig. 73.4).
Both surfaces of levator ani have a fascial covering; the combination of
Parietal pelvic fascia the two fascial layers and the intervening muscle is called the pelvic
The parietal pelvic fascia consists of the obturator fascia, the fasciae over diaphragm. On the inferior surface, the thin fascia is continuous with
piriformis, and over levator ani (the pelvic diaphragm) and the presac- the obturator fascia below the tendinous arch of levator ani laterally. It
ral fascia. covers the medial wall of the ischio-anal fossa and blends below with
fasciae on the urethral sphincter and the external anal sphincter. The
obturator fascia superior fascia of the pelvic diaphragm is markedly thicker than the
The parietal pelvic fascia on the pelvic (medial) surface of obturator inferior fascia and is attached anteriorly to the posterior aspect of
internus is well differentiated. In humans, ventral to the lateral attach- the body of the pubis, approximately 2 cm above its lower border. It
ment of the pelvic organs, a portion of it is derived from the degener- extends laterally across the superior pubic ramus, blending with the
Superficial abdominal fascia
Peritoneum Presacral fascia
Posterior mesorectal fascia
Anterior mesorectal fascia
Anococcygeal ligament
Suspensory ligament of the penis
Deep transverse perineal muscle
Endopelvic fascia
Perineal body
Perineal membrane
External anal sphincter
Superficial perineal fascia
Deep perineal fascia
Fig. 73.4 Fasciae of the pelvis and perineum: median sagittal section in the male. The visceral parietal fasciae have been omitted for clarity. | 1,696 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
True pelvis, pelvic floor and perineum
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obturator fascia and continuing along an irregular line to the spine of cervix, together with some of the pelvic autonomic nerves. A similar
the ischium. It is continuous posteriorly with the fascia over piriformis vesicosacral fold is present in the male.
and the anterior sacrococcygeal ligament. Medially, the superior fascia Approximately 1 cm above the inferior border of the pubic bone and
of the pelvic diaphragm blends with the visceral pelvic fascia to con- 1 cm lateral to the midline, a band of dense pelvic connective tissue
tribute to the endopelvic fascia. – the anterior end of the tendinous arch of the pelvic fascia – attaches
to the paravaginal tissues in the female and the prostatic tissues in the
Tendinous arch of the pelvic fascia/white line of the male. This band extends on the inner surface of levator ani and joins
parietal pelvic fascia the tendinous arch of levator ani to the ischium, just above the spine.
Low on the superomedial aspect of the upper fascia over levator ani, a The attachment of the paravaginal tissue to the pubic bones is some-
thick, white band of condensed connective tissue extends from the times called the pubourethral ligament, which is a misnomer since it
lower part of the pubic symphysis to the superior margin of the ischial is not attached to the urethra. The attachment of the anterior vaginal
spine. It provides attachment for the condensations of visceral pelvic wall to the tendinous arch of the pelvic fascia, the paravaginal attach-
fascia that provide support to the urethra and bladder, and to the vagina ment, helps to provide support to the vagina, urethra and bladder.
in females (see below). There is much less condensation of connective tissue around the
rectum. A layer presumed to be a peritoneal fusion fascia is described
presacral fascia between the rectum and either the seminal vesicles in the male or the
The presacral fascia forms a hammock-like structure behind the poste- vagina in the female (the rectovesical septum or rectovaginal septum,
rior portion of the mesorectal fascia. Laterally, it extends to the origin respectively); it does not connect to the rectum itself. The connective
of the fascia over piriformis and the fascia over levator ani (superior tissue over the longitudinal muscles of the rectum is thickened just
pelvic diaphragmatic fascia), with which it blends; more inferiorly, it above the anal hiatus in levator ani and fuses with the endopelvic fascia
extends between the white line of the parietal pelvic fascia on either and the anococcygeal ligament, forming a structure that is sometimes
side. Inferiorly, it extends to the anorectal junction, where it fuses with referred to as a rectosacral ligament.
the posterior aspect of the mesorectal fascia and the iliococcygeal raphe
at the level of the anorectal junction. Superiorly, it can be traced to the
origin of the superior hypogastric plexus, where it becomes progres- VASCULAR SUPPLY AND LYMPHATIC
sively thinner over the sacral promontory and becomes continuous with DRAINAGE OF THE PELVIS
the retroperitoneal tissues. The right and left hypogastric nerves and
inferior hypogastric plexuses lie on its surface, and the presacral veins The true pelvis contains the internal iliac arteries and veins, and the
lie immediately posterior to it. It forms a distinct layer that can be seen lymphatics that drain the majority of the pelvic viscera. The common
both on magnetic resonance images of the pelvis and during surgery. and external iliac vessels and the lymphatics that drain the lower limb
The presacral fascia provides an important landmark because extension lie along the pelvic brim and in the lower retroperitoneum, but are
of rectal tumours through it significantly reduces the possibility of cura- conveniently discussed together with the vessels of the true pelvis.
tive resectional surgery. Dissection in the plane posterior to the fascia Remarkable variation exists in the terminal branching pattern for the
may result in bleeding from the presacral veins; because the adventitia iliac vessels and no two individuals have quite the same anatomy.
of the veins is partly attached to the posterior surface of the fascia, the General patterns do, however, exist and this description will consider
haemorrhage may be severe (as the veins are unable to contract prop- the common pattern.
erly). The presacral fascia is a useful structure to which the rectum may
be sutured during rectopexy for rectal prolapse in children.
Arteries of the pelvis
Visceral pelvic fascia
Common iliac arteries
The urogenital organs in both sexes are connected bilaterally to the
pelvic walls by neurovascular mesenteric condensations ensheathed by The abdominal aorta bifurcates into the right and left common iliac
a meshwork of loose connective and adipose tissue and lying above the arteries anterolateral to the left side of the body of the fourth lumbar
perineal membrane (Roberts et al 1964, Ricci et al 1947, Reiffenstuhl vertebra (Roberts and Krishingner 1967). These arteries diverge as they
1982, Range and Woodburne 1964, Campbell 1950). The lateral attach- descend and they divide at the level of the sacroiliac joint into external
ments of the pelvic organs to the pelvic side walls are referred to as and internal iliac arteries. The external iliac artery is the principal artery
the endopelvic fascia. Considered as a unit, the connections provide a of the lower limb. The internal iliac artery provides the principal supply
conduit for conducting neurovascular elements from the pelvic side to the walls and viscera of the pelvis, the perineum and the gluteal
wall to the organs and attachments that help to retain the pelvic organs region.
in place; this factor is important in the female in preventing pelvic
organ prolapse (DeLancey 1992). The loose connective tissue associ- Right common iliac artery The right common iliac artery is
ated with these mesenteries extends to the midline, separating the approximately 5 cm long. It passes obliquely across part of the bodies
bladder from the vagina, and the vagina from the rectum, in the female; of the fourth and the fifth lumbar vertebrae, and is crossed anteriorly
it separates the bladder, prostate and seminal vesicles from the rectum by the sympathetic rami to the pelvic plexus and, at its division into
in the male. The fascial tissues contain varying amounts of connective internal and external iliac arteries, by the ureter. It is covered by the
tissue and smooth muscle; where they either are unusually dense or parietal peritoneum, which separates it from the coils of the small
form visible ridges, they are called ‘ligaments’ (e.g. cardinal ligament, intestine. Posteriorly, it is separated from the bodies of the fourth
uterosacral ligament). Clinically, these lateral attachments are often and fifth lumbar vertebrae and their intervening disc by the right sym-
referred to as visceral ‘ligaments’, but they are mesenteric in nature and, pathetic trunk, the terminal parts of the common iliac veins and the
therefore, quite unlike the bands of dense, regular, connective tissue start of the inferior vena cava, the obturator nerve, lumbosacral trunk
that typify skeletal ligaments. The lateral attachments of the mesenter- and iliolumbar artery. Laterally, the inferior vena cava and the right
ies sweep off the pelvic walls, arising from the superior fascia over common iliac vein lie superiorly and the right psoas major lies inferi-
levator ani and from part of the fascia over piriformis more superiorly orly. The left common iliac vein is medial to the upper part of the right
and posteriorly. The mesenteries passing to the bladder in the male, or common iliac artery.
the bladder and upper vagina and uterus in the female, are relatively
long, but these lateral connections become shorter towards the pelvic Left common iliac artery The left common iliac artery is shorter
outlet, until at the level of the perineal membrane, there is a direct than the right and is approximately 4 cm long. Lying anterior to it are
connection between the organs and the pelvic walls. the sympathetic rami to the pelvic plexus, the superior rectal artery and,
In the female, the cardinal ligament is the upper portion of this at its terminal bifurcation, the ureter. The sympathetic trunk, the bodies
mesentery. It surrounds the cervicovaginal junction and extends down of the fourth and fifth lumbar vertebrae and intervening disc, the obtu-
to mid-vagina, where the vagina has a more direct lateral attachment at rator nerve, lumbosacral trunk and iliolumbar artery are all posterior.
the tendinous arch of the pelvic fascia. The portions that attach to the The left common iliac vein is posteromedial, and the left psoas major
uterus and vagina are sometimes called the parametrium and paracol- lateral, to the left common iliac artery.
pium, respectively. Further accounts of the paravisceral portions of the
visceral pelvic fascia are given in the chapters describing the organs to Branches In addition to the external iliac and internal iliac branches,
which the fascia relates. each common iliac artery also gives small branches to the peritoneum,
The uterosacral ligament is a visible fold of tissue flanking the psoas major, ureter, adjacent nerves and surrounding areolar tissue. The
rectum as it descends posterior to the cervix in the female. It contains common iliac artery occasionally gives rise to the iliolumbar artery and
a considerable amount of smooth muscle near its attachment to the accessory or replaced renal arteries if the kidney is low-lying. | 1,697 | 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 anteroposterior diameters of the common, external and internal
iliac arteries are strongly correlated to body surface area (BSA) in chil-
dren, in contrast to adults, in whom the relationship is inconsistent.
Vessel diameters measured by ultrasonography are significantly larger
in boys than in girls. The relationship between vessel diameters and BSA
is shown in Figure 73.7 (Munk et al 2002).
A Fig. 73.7 The relationship between
anteroposterior diameters of the right
Boys (1-16 years): common, internal and external iliac arteries
right common iliac artery
and body surface area (BSA) in boys and
(systolic phase)
girls between the ages of 1 and 16 years.
(With permission from Munk AL, Darge K,
Wiesel M, Troeger J, Diameter of the
infrarenal aorta and the iliac arteries in
children: ultrasound measurements.
Transplantation 2002;73:631–635.)
0
0.0 0.5 1.0
BSA (m2)
B
Boys (1-16 years):
right internal iliac artery
C
Boys (1-16 years):
right external iliac artery
D
Girls (1-16 years):
right common iliac artery
(systolic phase)
E
Girls (1-16 years):
right internal iliac artery
F
Girls (1-16 years):
right external iliac artery
)mm(
retemaiD
20
15
10
5
1.5 2.0
0
0.0 0.5 1.0
BSA (m2)
)mm(
retemaiD
20
15
10
5
1.5 2.0
0
0.0 0.5 1.0
BSA (m2)
)mm(
retemaiD
20
15
10
5
1.5 2.0
0
0.0 0.5 1.0
BSA (m2)
)mm(
retemaiD
0
0.0 0.5 1.0
BSA (m2)
20
15
10
5
1.5 2.0
)mm(
retemaiD
0
0.0 0.5 1.0
BSA (m2)
20
15
10
5
1.5 2.0
)mm(
retemaiD
20
15
10
5
1.5 2.0 | 1,698 | 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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Internal iliac arteries
trunk and sacroiliac joint are posterior. Laterally are the external iliac
Each internal iliac artery, approximately 4 cm long, begins at the vein, between the artery and psoas major, and the obturator nerve lying
common iliac bifurcation, level with the lumbosacral intervertebral disc inferior to the vein. The parietal peritoneum is medial, separating it
and anterior to the sacroiliac joint (Figs 73.5, 73.6). It descends poste- from the terminal ileum on the right and the sigmoid colon on the left,
riorly to the superior margin of the greater sciatic foramen, where it and tributaries of the internal iliac vein. For details of the considerable
divides into an anterior trunk, which continues in the same line towards variation in the anatomy of the internal iliac artery, see Roberts and
the ischial spine, and a posterior trunk, which passes back to the greater Krishingner (1967).
sciatic foramen. The anterior trunk primarily supplies the pelvic organs, In the fetus, the internal iliac artery is twice the size of the external
while the posterior trunk primarily supplies muscles in the hip and iliac artery and is the direct continuation of the common iliac artery.
back. Anterior to the artery are the ureter and, in females, the ovary and The main trunk ascends on the anterior abdominal wall to the umbili-
fimbriated end of the uterine tube. The internal iliac vein, lumbosacral cus, converging on the contralateral artery, and the two arteries run
Fig. 73.5 Arteries of the male pelvis.
Internal iliac artery
Iliolumbar artery
Superior gluteal artery
Ureter
Posterior trunk
Anterior trunk
Superior
Lateral sacral artery
vesical artery
Pudendal artery
Inferior gluteal artery
Obturator artery
Middle rectal artery
Obliterated right
umbilical artery Inferior vesical artery
Fig. 73.6 Arteries of the female pelvis.
Internal iliac artery
Iliolumbar artery
Superior gluteal artery
Posterior trunk
Superior Anterior trunk
vesical artery Pudendal artery
Uterine artery
Lateral sacral artery
Obturator artery
Inferior gluteal artery
Obliterated right Vaginal artery
umbilical artery Inferior vesical artery
Middle rectal artery | 1,699 | 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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through the umbilicus to enter the umbilical cord as the umbilical the posterior surface of the pubis. It supplies the distal end of the ureter,
arteries. At birth, when placental circulation ceases, only the pelvic the bladder, the proximal end of the vas deferens and the seminal vesi-
segment remains patent as the internal iliac artery and part of the supe- cles. It also gives origin to the umbilical artery in the fetus, which
rior vesical artery; the remainder becomes a fibrous medial umbilical remains as a fibrous cord – the medial umbilical ligament – in the adult.
ligament. Persistence of the umbilical artery has been described and This vessel occasionally remains patent as a small artery supplying the
may cause extrinsic obstruction of the distal ureter (Gupta et al 1999). umbilicus.
In males, the patent part (commonly, the superior vesical artery) usually
gives off an artery to the vas (ductus) deferens. Inferior vesical artery The inferior vesical artery may arise as a
common branch with the middle rectal artery. It supplies the bladder,
posterior trunk branches prostate, seminal vesicles and vas deferens in the male, and the bladder
The branches of the posterior trunk of the internal iliac artery are the in the female, where it is often replaced by the vaginal artery.
iliolumbar, lateral sacral and superior gluteal arteries.
Middle rectal artery The middle rectal artery runs into the lateral
Iliolumbar artery The iliolumbar artery is the first branch of the fascial coverings of the mesorectum. It often consists of multiple
posterior trunk and ascends laterally anterior to the sacroiliac joint and branches, may be small, and occasionally arises either close to, or in
lumbosacral nerve trunk. It lies posterior to the obturator nerve and common with, the origin of the inferior vesical artery in males.
external iliac vessels, and reaches the medial border of psoas major,
dividing behind it into the lumbar and iliac branches. The lumbar Vaginal artery In females, the vaginal artery may replace the inferior
branch supplies psoas major and quadratus lumborum, and anastomo- vesical artery. It may arise from the uterine artery close to its origin and
ses with the fourth lumbar artery. It sends a small spinal branch through can be a single vessel or multiple branches.
the intervertebral foramen between the fifth lumbar and first sacral
vertebrae, to supply the cauda equina. The iliac branch supplies iliacus; Obturator artery The obturator artery runs anteroinferiorly from the
between the muscle and bone, it anastomoses with the iliac branches anterior trunk on the lateral pelvic wall to the upper part of the obtura-
of the obturator artery. A large nutrient branch enters an oblique canal tor foramen. In the pelvis, it is related laterally to the fascia over obtura-
in the ilium. Other branches run around the iliac crest, contribute to tor internus and is crossed on its medial aspect by the ureter and, in
the supply of the gluteal and abdominal muscles, and anastomose the male, by the vas deferens. The obturator nerve runs above the artery,
with the superior gluteal, circumflex iliac and lateral circumflex femoral the obturator vein below it. The artery provides iliac branches to the
arteries (see Fig. 80.18). iliac fossa that supply the bone and iliacus and anastomose with
the iliolumbar artery. It gives off a vesical branch that runs medially to
Lateral sacral arteries The lateral sacral arteries are usually double; the bladder and sometimes replaces the inferior vesical branch of the
if they are single, they divide rapidly into superior and inferior branches. internal iliac artery. In the female, the ovary lies medial to the obturator
The superior and larger artery passes medially into the first or second artery. A pubic branch usually arises just before the obturator artery
anterior sacral foramen, supplies the sacral vertebrae and contents of leaves the pelvis; it ascends over the pubis to anastomose with the
the sacral canal, and then leaves the sacrum via the corresponding contralateral artery and the pubic branch of the inferior epigastric
dorsal foramen to supply the skin and muscles dorsal to the sacrum. artery.
The inferior or lateral sacral artery crosses obliquely anterior to piri- The obturator artery leaves the pelvis via the obturator canal and
formis and the sacral anterior spinal rami, and then descends lateral to divides into anterior and posterior branches that encircle the obturator
the sympathetic trunk to anastomose with its fellow and the median foramen between obturator externus and the obturator membrane. The
sacral artery anterior to the coccyx. Its branches enter the anterior sacral anterior branch curves anteriorly on the membrane and then inferiorly
foramina and are distributed in the same way as the branches of the along its anterior margin to supply branches to obturator externus,
superior artery. pectineus, the femoral adductors and gracilis. It anastomoses with the
posterior branch and the medial circumflex femoral artery. The poste-
Superior gluteal artery The superior gluteal artery is the largest rior branch follows the posterior margin of the foramen and turns
branch of the internal iliac artery and, effectively, forms the main con- anteriorly on the ischial part to anastomose with the anterior branch.
tinuation of its posterior trunk. It runs posteriorly between the lum- It supplies the muscles attached to the ischial tuberosity and anastomo-
bosacral trunk and the first sacral ramus, or between the first and second ses with the inferior gluteal artery. An acetabular branch enters the hip
rami, and then turns slightly inferiorly, leaving the pelvis by the greater joint at the acetabular notch, ramifies in the fat of the acetabular fossa
sciatic foramen above piriformis and dividing into superficial and deep and sends a branch along the ligament of the femoral head.
branches. In the pelvis, it supplies piriformis, obturator internus and a Occasionally, the obturator artery is replaced by an enlarged pubic
nutrient artery to the ilium. The superficial branch enters the deep branch of the inferior epigastric artery that descends almost vertically
surface of gluteus maximus. Its numerous branches supply the muscle to the obturator foramen. It usually lies near the external iliac vein,
and anastomose with the inferior gluteal branches (see Fig. 80.30), lateral to the femoral ring, and is rarely injured during inguinal or
while others perforate the tendinous medial attachment of the muscle femoral hernia surgery. Sometimes, it curves along the edge of the
to supply the skin over the sacrum, where they anastomose with the lacunar part of the inguinal ligament, partly encircling the neck of a
posterior branches of the lateral sacral arteries. The deep branch of the hernial sac, and may be inadvertently cut during enlargement of the
superior gluteal artery passes between gluteus medius and the bone, femoral ring in reducing a femoral hernia.
soon dividing into superior and inferior branches. The superior branch
skirts the superior border of gluteus minimus to the anterior superior Uterine artery The uterine artery is an additional branch in females.
iliac spine, and anastomoses with the deep circumflex iliac artery and It is a large artery that arises below the obturator artery on the lateral
the ascending branch of the lateral circumflex femoral artery. The infe- wall of the pelvis and runs inferomedially into the broad ligament of
rior branch runs through gluteus minimus obliquely, supplies it and the uterus (Ch. 77).
gluteus medius, and anastomoses with the lateral circumflex femoral
artery. A branch enters the trochanteric fossa to join the inferior gluteal Internal pudendal artery (pelvic portion) The internal pudendal
artery and ascending branch of the medial circumflex femoral artery; artery is the smaller terminal branch of the anterior division of the
other branches run through gluteus minimus to supply the hip joint. internal iliac artery. Close to its origin, it crosses anterior to piriformis,
The superior gluteal artery occasionally arises directly from the inter- the sacral plexus and the inferior gluteal artery. It descends laterally to
nal iliac artery with the inferior gluteal artery and sometimes from the the inferior rim of the greater sciatic foramen, where it leaves the pelvis
internal pudendal artery. between piriformis and ischiococcygeus, and enters the gluteal region
(see Fig. 77.3B). It next curves around the dorsum of the ischial spine
anterior trunk branches and enters the ischiorectal fossa via the lesser sciatic foramen. This
The branches of the anterior trunk of the internal iliac artery are the course effectively allows the nerve to wrap around the posterior limit
superior and inferior vesical, middle rectal, vaginal, obturator, uterine, of levator ani at its attachment to the ischial spine. Behind the ischial
internal pudendal and inferior gluteal arteries (see Fig. 73.6). Signifi- spine, the artery is covered by gluteus maximus, the pudendal nerve is
cant variation occurs in the branching patterns of the anterior trunk; medial, and the nerve to obturator internus is lateral. The artery traverses
the general principles will be considered here. the ischiorectal fossa in Alcock’s canal in the fascia covering obturator
internus; it gives off an inferior rectal branch early in its course through
Superior vesical artery The superior vesical artery is the first large the fossa (see Fig. 73.12). The internal pudendal artery gives off several
branch of the anterior trunk. It lies on the lateral wall of the pelvis, just muscular branches in the pelvis and gluteal region that supply adjacent
below the brim, and runs anteroinferiorly, medial to the periosteum of muscles and nerves. | 1,700 | 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 gluteal artery The inferior gluteal artery is the larger termi- ascends obliquely to end at the right side of the fifth lumbar vertebra,
nal branch of the anterior internal iliac trunk and principally supplies uniting at an acute angle with the contralateral vessel to form the infe-
the buttock and thigh. It descends posteriorly, anterior to the sacral rior vena cava. The right common iliac vein is shorter and more nearly
plexus and piriformis but posterior to the internal pudendal artery. It vertical, lying posterior, and then lateral, to its artery. The right obtura-
passes between either the first and second, or second and third, sacral tor nerve passes posteriorly. The left common iliac vein is longer and
ventral rami, then between piriformis and ischiococcygeus, before more oblique, and lies first medial, then posterior, to its artery. It is
running through the lower part of the greater sciatic foramen to reach crossed anteriorly by the attachment of the sigmoid mesocolon and
the gluteal region. The artery runs inferiorly between the greater tro- superior rectal vessels. Each vein receives iliolumbar and, sometimes,
chanter and ischial tuberosity, together with the sciatic and posterior lateral sacral veins. The left common iliac vein usually drains the
femoral cutaneous nerves, deep to gluteus maximus. It continues down median sacral vein. There are no valves in these veins.
the thigh, supplying the skin and anastomosing with branches of the The left common iliac vein occasionally ascends to the left of the
perforating arteries. The inferior gluteal and internal pudendal arteries aorta to the level of the kidney, where it receives the left renal vein and
often arise as a common stem from the internal iliac artery, sometimes crosses anterior to the aorta to join the inferior vena cava; this vessel
with the superior gluteal artery. In the pelvis, the inferior gluteal artery represents the persistent caudal half of the left postcardinal or supra-
gives branches to piriformis, ischiococcygeus and iliococcygeus, and cardinal vein.
occasionally contributes to the middle rectal arterial supply. In the
male, it may supply vessels to the seminal vesicles and prostate. Median sacral veins The right and left medial sacral veins accom-
pany the corresponding arteries anterior to the sacrum, where they unite
External iliac arteries
to form a single vein that usually ends in the left common iliac vein,
The external iliac arteries are of larger calibre than the internal iliac but which sometimes ends at the common iliac junction.
arteries (see Figs 73.5, 73.6). Each artery descends laterally along the
medial border of psoas major, from the common iliac bifurcation to a Internal pudendal veins The internal pudendal veins are venae
point midway between the anterior superior iliac spine and the pubic comitantes of the internal pudendal artery and unite as a single vessel
symphysis, and enters the thigh posterior to the inguinal ligament to that drains into the internal iliac vein. They receive veins from the
become the femoral artery. inferior rectal veins and either the penile bulb and scrotum (males), or
The parietal peritoneum and extraperitoneal tissue separate the right the clitoris and labia (females).
external iliac artery from the terminal ileum and, usually, the appendix,
and the left external iliac artery from the sigmoid colon and coils of Internal iliac vein
small intestine anteromedially. At its origin, the external iliac artery may The internal iliac vein is formed by the convergence of several veins
be crossed by the ureter; it is subsequently crossed by the gonadal above the greater sciatic foramen. It does not have the predictable
vessels, the genital branch of the genitofemoral nerve, the deep circum- trunks and branches of the internal iliac artery but its tributaries drain
flex iliac vein, and the vas deferens (male) or round ligament (female). the same territories. It ascends posteromedial to the internal iliac
Posteriorly, the artery is separated from the medial border of psoas artery to join the external iliac vein, forming the common iliac vein at
major by the iliac fascia. The external iliac vein lies partly posterior to the pelvic brim, anterior to the lower part of the sacroiliac joint. It is
its upper part but is more medial below. Laterally, it is related to psoas covered anteromedially by parietal peritoneum. Its tributaries are the
major, which is covered by the iliac and psoas fasciae. Numerous lymph gluteal, internal pudendal and obturator veins, which originate out-
vessels and nodes lie on its anterior and lateral aspects. side the pelvis; the lateral sacral veins, which run from the anterior
The external iliac artery is principally the artery of the lower limb surface of the sacrum; and the middle rectal, vesical, uterine and vagi-
and, as such, has few branches in the pelvis. Apart from giving off very nal veins, which originate in the venous plexuses of the pelvic viscera
small vessels to psoas major and neighbouring lymph nodes, the artery (Fig. 73.8).
has no branches until it gives off the deep circumflex iliac and inferior The venous drainage of the leg may be blocked by thrombosis
epigastric arteries, near to the point at which it passes under the inguinal involving the external iliac systems and the inferior vena cava. Under
ligament. these circumstances, the pelvic veins, particularly the internal iliac tribu-
taries, enlarge and provide a major avenue of venous return from the
Deep circumflex iliac artery The deep circumflex iliac artery femoral system. Surgical interference with these veins may seriously
branches laterally from the external iliac artery almost opposite the compromise venous drainage and precipitate oedema of one or
origin of the inferior epigastric artery (see Fig. 78.7A). It ascends and both legs.
runs laterally to the anterior superior iliac spine behind the inguinal
ligament in a sheath formed by the union of the transversalis and iliac Superior gluteal veins The superior gluteal veins are the venae
fasciae. There, it anastomoses with the ascending branch of the lateral comitantes of the superior gluteal artery. They receive tributaries that
circumflex femoral artery, pierces the transversalis fascia and skirts correspond to the branches of the superior gluteal artery and enter the
the internal lip of the iliac crest. About halfway along the iliac crest, it pelvis via the greater sciatic foramen, above piriformis. They join the
runs through transversus abdominis, and then between transversus internal iliac vein, frequently as a single trunk.
abdominis and internal oblique, to anastomose with the iliolumbar
and superior gluteal arteries. It gives off a large ascending branch at the Inferior gluteal veins The inferior gluteal veins are venae comitantes
anterior superior iliac spine that runs between internal oblique and of the inferior gluteal artery. They begin proximally and posterior in the
transversus abdominis, supplies both muscles, and anastomoses with thigh, where they anastomose with the medial circumflex femoral and
the lumbar and inferior epigastric arteries. first perforating veins, and they enter the pelvis low in the greater sciatic
foramen, joining to form a vessel that opens into the distal (lower) part
Inferior epigastric artery The inferior epigastric artery originates of the internal iliac vein. The inferior gluteal and superficial gluteal
from the external iliac artery posterior to the inguinal ligament. It curves veins connect by perforating veins (Doyle 1970) analogous to the sural
forwards in the anterior extraperitoneal tissue and ascends obliquely perforating veins. The gluteal veins probably have a venous ‘pumping’
along the medial margin of the deep inguinal ring; from here, it con- role, and provide collaterals between the femoral and internal iliac
tinues as an artery of the anterior abdominal wall. veins.
Veins of the pelvis Obturator vein The obturator vein begins in the proximal adductor
region and enters the pelvis via the obturator foramen. It runs posteri-
The true pelvis contains a large number of veins that drain the pelvic orly and superiorly on the lateral pelvic wall below the obturator artery
walls and most of the viscera contained within the pelvis, and also carry and between the ureter and internal iliac artery, and ends in the internal
venous blood from the gluteal region, hip and thigh. The external iliac iliac vein. It is sometimes replaced by an enlarged pubic vein, which
veins, which lie close to the brim of the pelvis, carry the venous drainage joins the external iliac vein.
from most of the lower limb. There is considerable variation in the
venous drainage of the pelvis: although the major veins frequently Lateral sacral veins The lateral sacral veins accompany the lateral
follow their named arterial counterparts, the small tributaries exhibit sacral arteries and are interconnected by a sacral venous plexus.
considerable inter-individual variation.
Middle rectal vein The middle rectal vein begins in the rectal venous
Common iliac veins plexus and drains the rectum and mesorectum. Variable in size, it runs
The common iliac vein is formed by the union of the external and laterally on the pelvic surface of levator ani to end in the internal iliac
internal iliac veins, anterior to the sacroiliac joints (see Fig. 78.8). It vein. The middle rectal vein often receives tributaries from the bladder | 1,701 | 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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Fig. 73.8 Veins of the female pelvis.
Internal iliac vein
Superior gluteal vein
Lateral sacral vein
Superior
vesical vein Pudendal vein
Obturator vein
Inferior gluteal
vein
Uterine vein
Middle rectal vein
Inferior vesical vein
and either the prostate and seminal vesicle (males) or the posterior They usually lie in medial, lateral and anterior chains around the
aspect of the vagina (females). common iliac artery, the lateral being the main route; one or two lie
inferior to the aortic bifurcation and anterior to the fifth lumbar verte-
External iliac vein
bra or sacral promontory. The common iliac nodes connect to the
The external iliac vein is the proximal continuation of the femoral vein lateral aortic nodes.
(see Figs 78.8, 80.33). It begins posterior to the inguinal ligament,
ascends along the pelvic brim, and ends anterior to the sacroiliac joint External iliac nodes
by joining the internal iliac vein to form the common iliac vein. On The external iliac nodes usually form three subgroups, which are lateral,
the right, it lies medial to the external iliac artery, gradually inclining medial and anterior to the external iliac vessels (see Fig. 77.3B). The
behind it as it ascends. On the left, it is wholly medial. Disease of the medial nodes are considered the main channel of drainage, collecting
external iliac artery may cause it to adhere closely to the vein at the lymph from the lower limb via the inguinal nodes, the deeper layers of
point where it is in contact, and, particularly on the right side, the walls the infra-umbilical abdominal wall, the adductor region of the thigh,
of the vessels may become fused, making dissection hazardous. The the glans penis or clitoris, the membranous urethra, prostate, fundus of
external iliac vein is crossed medially by the ureter and internal iliac the bladder, uterine cervix and upper vagina. Their efferents pass to the
artery. In males, it is crossed by the vas deferens, in females by the round common iliac nodes (see Fig. 78.10).
ligament and ovarian vessels. Psoas major lies laterally, except where
the artery intervenes. The vein is usually valveless but may contain a Inferior epigastric and circumflex iliac nodes The inferior
single valve. Its tributaries are the inferior epigastric, deep circumflex epigastric and circumflex iliac nodes are associated with their similarly
iliac and pubic veins. Agenesis of the external iliac vein has been named vessels and drain the corresponding areas to the external iliac
reported in association with Klippel–Trenaunay syndrome (Dogan et al nodes.
2003).
Internal iliac nodes
Inferior epigastric vein One or two inferior epigastric veins accom- The internal iliac nodes surround the branches of the internal iliac
pany the inferior epigastric artery and drain into the external iliac vein vessels. They receive afferents from most of the pelvic viscera (with the
a little above the inguinal ligament. exception of the gonads and the majority of the rectum), the deeper
parts of the perineum, and the gluteal and posterior femoral muscles,
Deep circumflex iliac vein The deep circumflex iliac vein is formed and drain to the common iliac nodes. The individual groups are con-
from venae comitantes of the corresponding artery. It joins the external sidered in the description of the viscera. There are frequent connections
iliac vein a little above the inferior epigastric vein, after crossing anterior between the right and left groups, particularly when they lie close to
to the external iliac artery. the anterior and posterior midlines (Fig. 73.9).
Pubic vein The pubic vein connects the external iliac and obturator
veins. It ascends on the pelvic surface of the pubis with the pubic branch INNERVATION OF THE PELVIS
of the inferior epigastric artery and sometimes replaces the normal
obturator vein. The pelvis contains the lumbosacral nerve trunk, the sacral and coccy-
geal plexuses, and the pelvic parts of the sympathetic and parasym-
Lymphatic drainage of the pelvis pathetic systems. Collectively, these nerves carry the somatic and
autonomic innervation to the majority of the pelvic visceral organs,
The lymph nodes in the pelvis are grouped around the common, and the muscles of the pelvic floor and perineum, the gluteal region
external iliac and internal iliac vessels, and are named accordingly and the lower limb.
(Nesselrod 1936). The ventral rami of the sacral and coccygeal spinal nerves form the
sacral and coccygeal plexuses (Fig. 73.10). The upper four sacral ventral
Common iliac nodes
rami enter the pelvis by the anterior sacral foramina, the fifth enters
The common iliac nodes receive the entire lymphatic drainage of the between the sacrum and coccyx, and the ventral ramus of the coccygeal
lower limb because they drain both internal and external iliac nodes. nerve curves forwards below the rudimentary transverse process of the | 1,702 | 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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first coccygeal segment. The first and second sacral ventral rami are of psoas major and descends over the pelvic brim, anterior to the sac-
large, the third to fifth diminish progressively in size, and the coccygeal roiliac joint, to join the first sacral ramus. The greater part of the second
ramus is the smallest. Each receives a grey ramus communicans from a and third sacral rami converge on the inferomedial aspect of the lum-
corresponding sympathetic ganglion. Visceral efferent rami leave the bosacral trunk in the greater sciatic foramen to form the sciatic nerve.
second to fourth sacral rami as the pelvic splanchnic nerves, containing The ventral and dorsal divisions of the nerves do not separate physically
preganglionic parasympathetic fibres to minute ganglia in the walls of from each other but their fibres remain separate within the rami; the
the pelvic viscera. ventral and dorsal divisions of each contributing root join within the
sciatic nerve. The fibres of the dorsal divisions will go on to form
Lumbosacral trunk and sacral plexus the common fibular nerve, and the fibres of the ventral division form
the tibial nerve. The sciatic nerve, occasionally, divides into common
fibular and tibial nerves inside the pelvis; when this occurs, the common
The sacral plexus is formed by the lumbosacral trunk, the first to third
fibular nerve usually runs through piriformis.
sacral ventral rami, and part of the fourth sacral ventral ramus
The sacral plexus lies against the posterior pelvic wall anterior to
(the remainder of the fourth sacral ventral ramus joins the coccygeal
piriformis, posterior to the internal iliac vessels and ureter, and behind
plexus).
the sigmoid colon on the left. The superior gluteal vessels run either
The lumbar part of the lumbosacral trunk contains part of the fourth
between the lumbosacral trunk and first sacral ventral ramus, or between
and all of the fifth lumbar ventral rami; it appears at the medial margin
the first and second sacral rami, while the inferior gluteal vessels
lie between either the first and second, or second and third, sacral
Common iliac nodes Posterior trunk nodes rami.
The sacral plexus is not commonly involved in malignant tumours
of the pelvis because it lies behind the relatively dense presacral fascia,
which resists all but locally very advanced malignant infiltration. When
it occurs, there is intractable pain in the distribution of the branches of
the plexus, which may be very difficult to treat. The plexus may also be
involved in the reticuloses or be affected by plexiform neuromas.
Branches of the sacral plexus
The branches of the sacral plexus are shown in Table 73.1.
The course and distribution of most of the branches of the sacral
plexus are covered fully in Section 9.
Table 73.1 Branches of the sacral plexus
Nerve Ventral divisions Dorsal divisions
Internal
iliac nodes Nerve to quadratus femoris and gemellus inferior L4, 5; S1
Nerve to obturator internus and gemellus superior L5; S1, 2
Superior Nerve to piriformis S2 (S1)
vesical nodes
Superior gluteal nerve L4, 5; S1
Middle Inferior gluteal nerve L5; S1, 2
rectal nodes Posterior femoral cutaneous nerve S2, 3 S1, 2
Tibial (sciatic) nerve L4, 5; S1, 2, 3
Obturator nodes
Common fibular (sciatic) nerve L4, 5; S1, 2
Uterine and lateral Perforating cutaneous nerve S2, 3
cervical nodes Vaginal nodes Pudendal nerve S2, 3, 4
Nerves to levator ani and external anal sphincter S4
Fig. 73.9 Lymphatic drainage of the female pelvis and urinary bladder.
Fig. 73.10 The lumbosacral plexus in the pelvis.
L4 root
L5 root
Lumbosacral trunk
S1 root
S2 root
Superior gluteal nerve S3 root
S4 root
Inferior gluteal nerve
Sciatic nerve
Nerve to piriformis
Obturator nerve
Perforating
cutaneous nerve
Coccygeal nerve(s)
Nerve to obturator internus
and superior gemellus Nerve(s) to levator ani
and coccygeus
Nerve to quadratus femoris
and inferior gemellus
Pudendal nerves
Posterior femoral cutaneous nerve | 1,703 | 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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Pudendal nerve (in the pelvis) geus, joins the minute coccygeal ventral ramus that emerges from the
sacral hiatus, and curves round the lateral coccygeal margin, piercing
The pudendal nerve arises from the ventral divisions of the second,
coccygeus to reach the pelvis. The small trunk that is formed in this way
third and fourth sacral ventral rami and is formed just above the supe-
is the coccygeal plexus. Anococcygeal nerves arise from it and form a
rior border of the sacrotuberous ligament and the upper fibres of ischi-
few fine filaments that pierce the sacrotuberous ligament to supply the
ococcygeus (Klink 1953, Sato 1980). It leaves the pelvis via the greater
adjacent skin.
sciatic foramen between piriformis and ischiococcygeus (see Fig.
73.10), enters the gluteal region and passes dorsal to the sacrospinous
Pelvic part of the sympathetic system
ligament, close to its attachment to the ischial spine, where it lies
medial to the internal pudendal vessels. It accompanies the internal
pudendal artery through the lesser sciatic foramen into the pudendal The pelvic sympathetic trunk lies in the extraperitoneal tissue, anterior
(Alcock’s) canal on the lateral wall of the ischio-anal fossa. In the pos- to the sacrum beneath the presacral fascia (Fig. 73.11), and supplies
terior part of the canal, it gives rise to the inferior rectal and perineal sympathetic innervation to the pelvic organs and vascular system. It lies
nerves; the dorsal nerve of the penis or clitoris continues ventrally medial or anterior to the anterior sacral foramina and has four or five
from this origin. interconnected ganglia. Above, it is continuous with the lumbar sym-
pathetic trunk. The right and left trunks converge below the lowest
Sacral visceral branches
ganglia and unite in the small ganglion impar anterior to the coccyx.
Visceral branches – the pelvic splanchnic nerves – arise from the second Grey rami communicantes pass from the ganglia to sacral and coccygeal
to fourth sacral ventral rami and innervate the pelvic viscera. spinal nerves but there are no white rami communicantes. Medial
branches connect across the midline, and twigs from the first two
Sacral muscular branches
ganglia join the inferior hypogastric plexus or the hypogastric ‘nerve’.
Several muscular branches arise from the fourth sacral ventral ramus to
Other branches form a plexus on the median sacral artery.
supply the superior surface of levator ani and the upper part of the
external anal sphincter. The branches to levator ani enter the superior Vascular branches
(pelvic) surface of the muscle whilst the branch to the external anal
Preganglionic fibres for the vessels supplying the pelvis and lower limb
sphincter (also referred to as the perineal branch of the fourth sacral
are derived from the lower three thoracic and upper two or three lumbar
nerve) reaches the ischio-anal fossa by running either through ischio-
spinal segments. They reach the lower thoracic and upper lumbar
coccygeus, or between ischiococcygeus and iliococcygeus. It supplies the
ganglia through white rami communicantes and descend through the
skin between the anus and coccyx via its cutaneous branches.
sympathetic trunk to synapse in the lumbar ganglia. Postganglionic
fibres pass from these ganglia via grey rami communicantes to the
Coccygeal plexus
femoral nerve, which carries them to the femoral artery and its branches.
Some fibres descend through the lumbar ganglia to synapse in the
The coccygeal plexus is formed by a small descending branch from the upper two or three sacral ganglia, from which postganglionic axons pass
fourth sacral ramus and by the fifth sacral and coccygeal ventral rami. through grey rami communicantes to the roots of the sacral plexus.
The fifth sacral ventral ramus emerges from the sacral hiatus, curves Those in the pudendal and superior and inferior gluteal nerves accom-
round the lateral margin of the sacrum below its cornu, and pierces pany the arteries of the same name to the gluteal and perineal tissues;
ischiococcygeus from below to reach its upper, pelvic, surface. Here it branches may also supply the pelvic lymph nodes. Those joining the
is joined by a descending branch of the fourth sacral ventral ramus; the tibial nerve are carried to the popliteal artery and distributed via its
small trunk so formed descends on the pelvic surface of ischiococcy- branches to the leg and foot.
A Left sacral
Superior hypogastric plexus sympathetic trunk
B
Left sympathetic
trunk and ganglion
Right hypogastric nerve
Right inferior
hypogastric
plexus
Obturator
nerve
Sacral
sympathetic
ganglia
Ganglion impar
Right inferior
hypogastric plexus
Sacral sympathetic nerves
Autonomic fibres to pelvic vicera Pelvic parasympathetic nerves (S2,3,4)
Fig. 73.11 Autonomic nerves of the pelvis. | 1,704 | 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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Sympathetic denervation of vessels in the lower limb can be effected deep fascia of the anal triangle
by removing or ablating the upper three lumbar ganglia and the inter- The deep fascia (fascia musculorum) lines the inferior surface of levator
vening parts of the sympathetic trunk, which is used, rarely, in treating ani and is continuous at its lateral origin with the fascia over obturator
vascular insufficiency of the lower limb. internus below the attachment of levator ani. It lines the deep portion
of the ischio-anal fossa and its lateral walls.
PERINEUM Ischio-anal fossa
The ischio-anal fossa is an approximately horseshoe-shaped region
MUSCLES AND FASCIAE OF THE PERINEUM filling the majority of the anal triangle. Although often referred to as a
space, it is filled with loose adipose tissue and occasional blood vessels
and nerves (see Fig. 73.12). The ‘arms’ of the horseshoe are triangular
The perineum is an approximately diamond-shaped region that lies
in cross-section because levator ani slopes medially from its lateral
below levator ani, between the inner aspects of the thighs and anterior
pelvic origin towards the anorectal junction (see Fig. 66.44). The anal
to the sacrum and coccyx. It is usually described as if from the position
canal and its sphincters lie in the centre of the horseshoe. Above them,
of an individual lying supine with the hip joints in abduction and
the medial limit of the fossa is formed by the deep fascia over levator
partial flexion. The surface projection of the perineum and the form of
ani. The outer boundary of the fossa is formed anterolaterally by the
the skin covering it vary considerably, depending on the position of the
fascia over obturator internus and the periosteum of the ischial tuber-
thighs, whereas the deep tissues themselves occupy relatively fixed posi-
osities. Posterolaterally, the outer boundary is formed by the lower
tions. The perineum is bounded anteriorly by the pubic symphysis and
border of gluteus maximus and the sacrotuberous ligament.
its arcuate ligament, posteriorly by the coccyx, anterolaterally by the
There is an anterior recess to the ischio-anal fossa that lies cranial to
ischiopubic rami and the ischial tuberosities, and posterolaterally by
the perineal membrane and transverse perineal muscles. It extends
the sacrotuberous ligaments. The deep limit of the perineum is the
anteriorly as far as the posterior surface of the pubis, below the attach-
inferior surface of the pelvic diaphragm, and its superficial limit is the
ment of levator ani. Posteriorly, the fossa contains the attachment of
skin that is continuous with that over the medial aspect of the thighs
the external anal sphincter to the tip of the coccyx; above and below
and the lower abdominal wall. An arbitrary line joining the ischial
this, the adipose tissue of the fossa is uninterrupted across the midline.
tuberosities (the inter-ischial line) divides the perineum into an ante-
These continuations of the ischio-anal fossa mean that infections,
rior urogenital triangle and a posterior anal triangle. The urogenital
tumours and fluid collections within not only may enlarge relatively
triangle faces downwards and forwards, whereas the anal triangle faces
freely to the side of the anal canal, but also may spread with little resist-
downwards and backwards at an approximate angle of 120° from the
ance to the contralateral side and deep to the perineal membrane. The
plane of the urogenital triangle.
internal pudendal vessels and accompanying nerves lie in the lateral
The male urogenital triangle contains the bulb and attachments of
wall of the ischio-anal fossa, enclosed in fascia forming the pudendal
the penis (Fig. 73.12) (Ch. 76), and the female urogenital triangle
canal. The inferior rectal vessels and nerves cross the fossa from the
contains the mons pubis, the labia majora, the labia minora, the clitoris
pudendal canal and often branch within it.
and the vaginal and urethral orifices (Ch. 77).
The ischio-anal fossa is an important surgical plane during resections
Anal triangle of the anal canal and anorectal junction for malignancy. It provides an
easy, relatively bloodless, plane of dissection that encompasses all of
the muscular structures of the anal canal and leads to the inferior
The structure of the anal triangle is similar in males and females, the
surface of levator ani, through which the dissection is carried.
main difference reflecting the wider transverse dimension of the triangle
in females that is associated with giving birth. The anal triangle contains External anal sphincter
the anal canal and its sphincters, and the ischio-anal fossa and its con- The external anal sphincter is a band of striated muscle that surrounds
tained nerves and vessels. It is lined by superficial and deep fascia. the lowest part of the anal canal (Oh and Kark 1972, Dalley 1987,
Lawson 1974b). The uppermost (deepest) fibres blend with the lowest
superficial fascia of the anal triangle fibres of puborectalis; the two are seen to be contiguous on endoanal
The superficial fascia (subcutaneous tissue; tela subcutanea) of the ultrasound and magnetic resonance imaging. Anteriorly, some of these
region is thin and is continuous with the superficial/subcutaneous upper fibres decussate into the superficial transverse perineal muscles.
fascia of the skin of the perineum, thighs and buttocks. Posteriorly, fibres are attached to the anococcygeal raphe. The majority
Fig. 73.12 Muscles and fasciae
Corpus cavernosum
of the male perineum. On the left
Corpus spongiosum side, the skin and superficial
fascia of the perineum only have
Ischiocavernosus Dorsal artery of the penis been removed. The posterior
scrotal (perineal) artery has been
Bulbospongiosus
Deep artery of the penis shown as it runs forwards into
Posterior scrotal the scrotal tissues. On the right
(perineal) artery side, the corpora cavernosa and
Artery of the bulb corpus spongiosum and their
Perineal membrane
associated muscles, the
Superficial transverse Deep transverse superficial perineal muscles and
perineal muscle perineal muscle perineal membrane have been
Transverse perineal artery Puborectalis removed to reveal the underlying
Perineal body Internal pudendal artery deep muscles and arteries of the
Ischio-anal fat Levator ani (iliococcygeal) perineum. All veins and nerves
have been omitted for clarity.
Inferior rectal artery
Lower fibres of external Upper fibres of external
anal sphincter anal sphincter
Anococcygeal raphe
Coccyx | 1,705 | 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 the middle fibres of the external anal sphincter surround the lower genital diaphragm – consisting of urogenital sphincter muscles sand-
part of the internal sphincter and are attached anteriorly in the perineal wiched between two layers of fascia and connected to the perineal body,
body, and posteriorly to the coccyx via the anococcygeal ligament. Some the periosteum of the ischiopubic rami and the arcuate ligament of the
fibres from each side of the sphincter decussate in these areas to form pubis, and perforated by the urethra and vagina. Oelrich introduced the
a sort of commissure in the anterior and posterior midline. The anterior alternative term ‘perineal membrane’ (Oelrich 1983). Recent detailed
and posterior attachments of the external anal sphincter give the mus- histological examination of serial cross-sections supports the concept
cular tube an oval profile lying anteroposteriorly. A subcutaneous of the perineal membrane as part of a larger interconnected support
portion encircles the anal verge and creates the radial skin creases sur- apparatus. It has distinct dorsal and ventral portions that are intimately
rounding the anus. The lower fibres lie below the level of the internal connected with levator ani: the dorsal portion is related to the support
anal sphincter and are separated from the lowest anal epithelium by of the perineal body and lateral vaginal wall by its attachment to the
submucosa. The thickness of the external anal sphincter in children is ischiopubic ramus, and the ventral portion is contiguous with the ure-
positively correlated with age (de la Portilla and López-Alonso 2009, thral supportive apparatus (Stein and DeLancey 2008). The perineal
Rehman et al 2011). membrane is particularly thick where it is attached to the arcuate liga-
ment of the pubis, and is here referred to as the transverse perineal liga-
anococcygeal ligament and iliococcygeal raphe ment. The posterior border of the perineal membrane is continuous
The anococcygeal ligament is a musculotendinous structure running with the deep part of the perineal body at its dorsal margin, and is
between the middle portion of the external anal sphincter and the continuous with the fascia over the superficial transverse perineal
coccyx. The iliococcygeal raphe (the decussation of the posterior fibres muscles.
of iliococcygeus) lies just above the anococcygeal ligament and is sepa- In the male, the perineal membrane is crossed by several structures:
rated from the rectum by presacral fascia. These structures are often the urethra, which traverses it 2–3 cm behind the inferior border of the
referred to as the postanal plate. Division of the anococcygeal raphe pubic symphysis; the vessels and nerves to the bulb of the penis; the
may cause descent of the anal canal and a lowering of the posterior part ducts of the bulbourethral glands, posterolateral to the urethral orifice;
of the anal triangle, but does not demonstrably interfere with the the deep dorsal vessels and dorsal nerves of the penis, behind the pubic
process of defecation. arch in the midline; and the posterior scrotal vessels and nerves, ante-
rior to the transverse perinei.
Urogenital triangle In the female, the perineal membrane is divided almost into two
halves by the vagina and urethra, such that it forms a triangle on each
side of these structures. The lateral margins of the vagina are attached
The urogenital triangle is bounded posteriorly by the inter-ischial line,
to the perineal membrane at the level of the hymenal ring, and levator
which usually overlies the posterior border of the transverse perineal
ani lies on its cranial surface. The ducts of Bartholin’s glands are at this
muscles. Anteriorly and laterally, it is bounded deeply by the pubic
level in the posterior lateral introitus. The deep dorsal vessels and dorsal
symphysis and ischiopubic rami. In males, the urogenital triangle
nerves of the clitoris lie within its fibres.
extends superficially to encompass the scrotum and the root of the
penis. In females, it extends to the lower limit of the labia and mons
Urethral sphincter mechanism
pubis. The urogenital triangle is divided into two parts by a strong
perineal membrane: the deep perineal space lies above the membrane,
and the superficial perineal space lies below it. The urethral sphincter mechanism consists of both striated and smooth
The female urogenital triangle includes muscles, fasciae, erectile muscle sphincters (Oelrich 1980, Oelrich 1983, Huisman 1983). The
structures and spaces similar to those in the male. There are some dif- striated urogenital sphincter has an upper circular element that sur-
ferences in size and disposition caused by the presence of the vagina rounds the urethra in the female and the apex of the prostate in the male,
and female external genitalia. between the vesical neck and perineal membrane. In the female, at the
level of the perineal membrane, it extends laterally outside of the urethra
Deep perineal space
in two arch-shaped bands that lie on the cranial surface of the perineal
perineal membrane membrane (Fig. 73.13). One, the compressor urethrae, follows the pubic
For many years, it was thought that the anterior pelvic outlet was arch to attached connective tissue in this area near the inner surface of
spanned by a triangular, trilaminar, musculofascial structure – the uro- the ischiopubic ramus. The other, the urethrovaginal sphincter, extends
A B
Pubic symphysis Body of clitoris
Pubis Urethra
Urinary bladder
Crus of clitoris
Inferior pubic ramus
Vagina
Ischiocavernosus
Compressor
Bulbospongiosus urethrae
Cut edge of superficial Bulb of vestibule
Sphincter
perineal fascia
Deep transverse urethrae
Vaginal wall
perineal muscle
Perineal membrane
Compressor
Superficial transverse Perineal body urethrae
perineal muscle
Sacrotuberous
Puborectalis ligament Urethra
Levator ani Anus
(iliococcygeus)
External Vagina Sphincter
anal sphincter urethrovaginalis
Gluteus maximus
Coccyx
Fig. 73.13 Muscles of the female perineum. A, On the right side, the membranous layer of superficial fascia has been removed (note the cut edge). On
the left side, superficial perineal muscles and overlying fascia have been removed to show the deep perineal muscles. B, The continuity of the deep
perineal muscles with sphincter urethrae. | 1,706 | 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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caudally to surround the lateral margin of the vaginal wall. In the male, ligament of the penis or clitoris, and the fasciae of external oblique and
these lateral extensions are not well developed and the sphincter in this the rectus sheath.
area primarily encircles the membranous urethra, forming a robust con-
strictor at this level. The smooth muscle sphincter consists of circularly Superficial and subcutaneous perineal
orientated smooth muscle cells that lie between the striated sphincter pouches
and the longitudinal smooth muscle and urethral lumen. It is not well
subcutaneous perineal pouch
developed. In children, the inner diameter of the urethral sphincter
The subcutaneous perineal pouch lies between the deep perineal fascia
increases with age: a cutoff value of 3 mm has been reported to predict
and the superficial perineal fascia. Under normal circumstances, these
detrusor–sphincter incoordination (Kakizaki et al 2003).
two layers are only separated by relatively thin subcutaneous connective
tissue; the skin of the anterior perineum and external genitalia is rela-
Innervation The urethral sphincter mechanism extends from the peri-
tively mobile over the deeper structures. However, this pouch is capable
neum through the urogenital hiatus into the pelvic cavity. It probably
of expanding considerably in the presence of fluid accumulation; blood,
receives innervation via the perineal branch of the pudendal nerve from
urine or fluid collecting in the subcutaneous pouch following trauma
below, and direct branches from the sacral plexus and the pelvic
or surgery on the urogenital triangle will spread throughout the tissues
splanchnic nerves from above. All these nerves originate in the second,
of the triangle, including the scrotum or labia majora, but cannot pass
third and fourth sacral spinal segments.
posteriorly into the anal triangle or laterally into the medial thigh
because of the firm tethering of the posterior attachments of the sub-
Actions Urinary incontinence is primarily a problem that affects cutaneous fascia. Since the superficial perineal fascia is in continuity
women and is more common after childbirth. Continence in women with the fascia of the anterior abdominal wall, fluid, blood or pus may
is maintained by an elegantly orchestrated system of muscles and con- also track freely between the subcutaneous tissues of the anterior
nective tissue that involves the urethral sphincters and the tissues that abdominal wall and the subcutaneous perineal pouch (e.g. postsurgical
support them. The urethral sphincter mechanism compresses the mid- haematomas of the abdominal wall readily cause discolouration of the
urethra in females and membranous urethra in males, particularly perineal and genital skin).
when the bladder contains fluid. Its location around the region of
highest urethral closing pressure suggests that it plays an important role superficial perineal pouch
in the continence of urine. At rest, activity of both the smooth and stri- The superficial perineal pouch lies below the perineal membrane and
ated sphincters contributes to this closure and, during times of increased is limited superficially by the deep perineal fascia (investing fascia of
need, voluntary contraction of the striated sphincter augments this the superficial perineal muscles) (Fig. 73.14). It contains the corpora
closure. In the distal portion of the urethra, where it is adjacent to the cavernosa and corpus spongiosum, ischiocavernosus, bulbospongiosus
perineal membrane, arch-shaped components of the striated sphincter and the superficial transverse perineal muscles, and branches of the
(compressor urethrae and urethrovaginal sphincter) pass between the pudendal vessels and nerves. In the female, it is crossed by the urethra
urethra and pubic bone, and contraction compresses the lumen until it and vagina and contains the clitoris. In the male, it contains the urethra
is closed. All muscles are relaxed during micturition to aid voiding, but as it runs in the root of the penis. It is a fully confined space; injuries
striated muscle contraction can help to expel final drops of urine, or of to the contents of the space (such as bleeding into the urethra in the
semen in the male, from the bulbar urethra. penile root) do not communicate with the deep or subcutaneous
During increases in abdominal pressure that occur, for example, pouches unless the fascial coverings are also lacerated or breached.
during a cough, bladder pressure rises above the normal urethral
closure pressure that keeps the lumen of the urethra closed. In this perineal body
situation, the rise in urethral closure pressures (called pressure trans- The perineal body is not a structure but an aggregation of fibromuscular
mission) that prevents urine leakage occurs because the urethra is tissue located in the midline at the junction between the anal and
compressed against the fascial tissues that lie between it and the urogenital triangles, just ventral to the anal sphincter (Oh and Kark
vaginal wall. If this layer is stable and unyielding, the urethra can be 1973). It is attached to many structures in both the deep and superficial
compressed closed against it, but if it is not well supported, this mech- urogenital spaces. Posteriorly, it merges with fibres from the middle part
anism is less effective and leakage can occur (DeLancey 1994). Overall of the external anal sphincter and the conjoint longitudinal coat. Supe-
continence during such events is a combination of sphincter constric- riorly, it is continuous with the rectoprostatic or rectovaginal septum,
tion due to the actions of the muscles in the urethral wall and pressure including fibres from levator ani (puborectalis or pubovaginalis). Ante-
transmission; sphincter function is the predominant factor (DeLancey riorly, it receives a contribution from the deep and superficial transverse
et al 2008). perineal muscles and bulbospongiosus (see Figs 73.4, 73.13). The peri-
neal body is continuous with the perineal membrane and the superfi-
Superficial and deep perineal fasciae
cial perineal fascia. Since the latter runs forwards into the skin of the
superficial perineal fascia perineum, the perineal body is tethered to the central perineal skin,
The tissue commonly referred to as the superficial fascia of the peri- which is often puckered over it. In males, this is continuous with the
neum (Colles’ fascia) forms a clear, surgically recognizable, plane perineal raphe in the skin of the scrotum. In females, the perineal body
beneath the skin of the anterior perineum (Tobin and Benjamin 1949). lies directly posterior, and is attached, to the posterior commissure of
It is firmly attached posteriorly to the fascia over the superficial trans- the labia majora and the introitus of the vagina.
verse perineal muscles and the posterior limit of the perineal mem- Spontaneous lacerations of the perineal body sustained during
brane. Laterally, it is attached to the margins of the ischiopubic rami as childbirth are often associated with damage to the anterior fibres of the
far back as the ischial tuberosities. From here, it runs more superficially external anal sphincter. The deliberate division of the perineal body to
to the skin of the urogenital triangle, lining the skin of the external facilitate delivery (episiotomy) is sometimes angled laterally to avoid
genitalia; in the male, it is also continuous with the fascial layer in the such sphincteric injuries. The perineal body is often used to position
skin of the scrotum that contains the dartos muscle. In females, the radiological markers in the assessment of pelvic floor dysfunction.
fascia follows the same limits but is much less extensive in the labia
majora. This layer runs anteriorly and superiorly into the skin of the superficial transverse perineal muscles
lower abdominal wall where it is continuous with the membranous The superficial transverse perineal muscles are narrow strips of muscle
fascia (Scarpa’s fascia). English-speaking anatomists refer to these tissue that run more or less transversely across the superficial perineal space
layers as a ‘superficial fascia’ but this is a misnomer; more accurately, anterior to the anus, from the medial and anterior aspects of the ischial
they constitute the membranous layer of subcutaneous tissue (tela tuberosities to the perineal body (see Fig. 73.13). A few fibres may also
subcutanea). pass into the ipsilateral bulbospongiosus or external anal sphincter.
They are occasionally small and may be absent.
deep perineal fascia (investing fascia of the
superficial perineal muscles) Bulbospongiosus
The tissue commonly referred to as the deep perineal fascia is a layer Bulbospongiosus differs between the sexes. In the male, it lies in the
of fascia that overlies the superficial muscles of the perineum midline, anterior to the perineal body (see Fig. 73.12). It consists of
(bulbospongiosus, ischiocavernosus, superficial transverse perineal two symmetrical parts united by a median fibrous raphe. The fibres
muscles). It is, in effect, the investing fascia of the superficial perineal attach to the perineal body, in which they decussate, and to the trans-
muscles and, as such, is firmly attached to the borders of the muscles verse superficial perinei and the external anal sphincter; they diverge
at attachments to the ischiopubic rami, posterior margin of the perineal like the sides of a feather from the median raphe. A thin layer of pos-
membrane and perineal body. Anteriorly, it fuses with the suspensory terior fibres joins the posterior portion of the perineal membrane. The | 1,707 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
True pelvis, pelvic floor and perineum
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Bladder Fascia over levator ani
White line of pelvic fascia Thick fascia over
obturator internus
Tendinous arch
of levator ani
Ilium
Obturator internus
Urethra
Obturator membrane
Levator ani
Thin fascia over
Prostate
obturator internus
Corpus spongiosum Thin endopelvic fascia
Ischiopubic ramus
Corpus cavernosum
Deep
perineal fascia
Ischiocavernosus
Deep transverse
perineal muscle
Bulbospongiosus
Perineal membrane
Skin of perineum and thigh
Superficial
perineal fascia
Fig. 73.14 Muscles and fasciae of the male perineum: coronal view. The section passes through the bulb of the penis at the level of the urethra. The
deep perineal space is continuous with the ischio-anal fossa posteriorly. The visceral and parietal fasciae have been omitted for clarity. The pelvic fascia
over the ‘pelvic’ aspect of the deep transverse perinei is very thin and does not form a distinct layer: in places it blends with the parietal pelvic fascia
over the inferior aspect of levator ani.
majority of the middle fibres encircle the bulb of the penis and adjacent VASCULAR SUPPLY AND LYMPHATIC DRAINAGE OF
corpus spongiosum, and attach to an aponeurosis on the dorsal sur- THE PERINEUM
faces. The anterior fibres spread out over the sides of the corpora cav-
ernosa, ending partly in them, anterior to ischiocavernosus, and partly Arteries of the perineum
in a tendinous expansion that covers the dorsal vessels of the penis. In
the female, bulbospongiosus also attaches to the perineal body, but the
Internal pudendal artery (in the perineum)
muscle on each side is separate and covers the superficial parts of the
The internal pudendal artery enters the perineum around the posterior
vestibular bulbs and greater vestibular glands (see Fig. 73.13). Fibres
aspect of the ischial spine and runs on the lateral wall of the ischio-anal
run anteriorly on either side of the vagina to attach to the corpora
fossa in the pudendal (Alcock’s) canal with the pudendal veins and the
cavernosa clitoridis, and a few fibres cross over the dorsum of the body
pudendal nerve. The canal lies about 4 cm above the lower limit of the
of the clitoris.
ischial tuberosity and is formed by connective tissue binding the vessels
and nerve to the medial surface of the fascia covering obturator inter-
Actions In the male, bulbospongiosus helps to empty the urethra of
nus. As the artery approaches the margin of the ischial ramus, it pro-
urine after the bladder has emptied. It may assist in the final stage of
ceeds above or below the perineal membrane, along the medial margin
erection as the middle fibres compress the erectile tissue of the bulb
of the inferior pubic ramus, en route to its target structures.
and the anterior fibres contribute by compressing the deep dorsal vein
In the male, the internal pudendal artery distal to the perineal artery
of the penis. It contracts six or seven times during ejaculation, assisting
gives a branch to the bulb of the penis before it divides into the cavern-
in the expulsion of semen. In the female, bulbospongiosus acts to
ous (deep, cavernosal) and dorsal arteries of the penis (see Fig. 73.12).
constrict the vaginal orifice and express the secretions of the greater
Given its distribution, the internal pudendal artery distal to its perineal
vestibular glands. Anterior fibres contribute to erection of the clitoris
branch has been named the artery of the penis. The artery to the bulb
by compressing its deep dorsal vein.
supplies the corpus spongiosum, and the cavernous artery of the penis
supplies the corpus cavernosum on each side. The dorsal artery runs
ischiocavernosus
on the dorsal aspect of the penis and supplies circumflex branches
In the male, ischiocavernosus covers the crus penis. It is attached by
to the corpora cavernosa and corpus spongiosum that end by anasto-
tendinous and muscular slips to the medial aspect of the ischial tuber-
mosing in the coronal sulcus and supplying the glans penis and its
osity posteriorly, and to the ischial ramus on both sides of the crus (see
overlying skin.
Fig. 73.12). These fibres end in an aponeurosis that is attached to the
In the female, a similar branch of the pudendal artery is distributed
sides and undersurface of the crus penis. In the female, ischiocavernosus
to the erectile tissue of the corpus spongiosum and vagina. The cavern-
is related to the crus of the clitoris but is otherwise similar to the cor-
ous artery supplies the corpora cavernosa of the clitoris; the dorsal artery
responding muscle in the male (Figs 73.15–73.16).
supplies the glans and prepuce of the clitoris.
Branches of the internal pudendal artery are sometimes derived from
Actions Ischiocavernosus compresses the crus penis in males and may an accessory pudendal artery, which is usually a branch of the pudendal
help to maintain penile erection. The muscles form a triangle on each artery before its exit from the pelvis; effectively, the artery is double
side of the midline with bulbospongiosus medially and the superficial before it leaves the pelvis.
transverse perineal muscles posteriorly, attached to the perineal mem-
brane; when contracted, the two ischiocavernosi act together to stabilize Inferior rectal artery
the erect penis. In the female, ischiocavernosus may help to promote The inferior rectal artery arises just after the internal pudendal artery
increased pressure in the clitoris. enters the pudendal canal on the lateral wall of the ischio-anal fossa. It | 1,708 | 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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Thick fascia over obturator internus
Tendinous arch of levator ani
Fascia over levator ani
White line of pelvic fascia
Ilium
Bladder
Obturator internus
Obturator membrane
Thin fascia over obturator internus
Levator ani
Urethra
Thin endopelvic fascia
Crus of clitoris
Ischiopubic ramus
Ischiocavernosus
Deep perineal fascia
Bulbospongiosus
Deep transversus perineal muscle
Bulb of vestibule
Perineal membrane
Superficial perineal fascia
Skin of perineum and thigh
Fig. 73.15 Muscles and fasciae of the female perineum – coronal view. The section passes through the bulb of the clitoris at the level of the urethra. The
deep perineal space is continuous with the ischio-anal fossa posteriorly. The visceral and parietal fasciae have been omitted for clarity. The pelvic fascia
over the ‘pelvic’ aspect of the deep transverse perinei is very thin and does not form a distinct layer: in places it blends with the parietal pelvic fascia
over the inferior aspect of levator ani.
Uterine Fig. 73.16 Muscles and fasciae of the female
cavity perineum: coronal T2-weighted magnetic
resonance image. (Courtesy of Dr J Lee and Ms K
Wimpey, Chelsea and Westminster Hospital,
Bladder London.)
Acetabulum
Obturator
internus Deep perineal space
Urethra
Levator ani
Deep transverse
perineal muscle
Ischiopubic ramus
Crus of clitoris
Superficial perineal
fascia Ischiocavernosus
Skin of perineum and thigh
runs anteromedially through the adipose tissue of the ischio-anal fossa contralateral artery and with the posterior scrotal and inferior rectal
to reach the deep portion of the external anal sphincter, and often arteries. It supplies the transverse perinei, the perineal body and the
branches before reaching the sphincter. During dissections of the anal posterior attachment of the bulb of the penis. The posterior scrotal
canal, particularly during perineal excisions of the anorectum, the infe- arteries are usually terminal branches of the perineal artery but may
rior rectal vessels are encountered in the ischio-anal fossa and must be also arise from its transverse branch. They are distributed to the scrotal
secured before division; otherwise, they tend to retract laterally to the skin and dartos muscle in the male and supply the perineal muscles.
canal, where they can cause troublesome bleeding. In the female, the perineal artery runs an almost identical course to that
in the male and gives off the posterior labial arteries (see Fig. 77.4).
Perineal artery
The perineal artery is a branch of the internal pudendal artery that arises
Veins of the perineum: internal
near the anterior end of the pudendal canal and runs through the peri-
pudendal veins
neal membrane. In the male, it approaches the scrotum in the superfi-
cial perineal space, between bulbospongiosus and ischiocavernosus (see
Fig. 76.24). A small transverse branch passes medially, inferior to the The internal pudendal veins are venae comitantes of the internal puden-
superficial transverse perineal muscle, to anastomose with the dal artery and unite as a single vessel ending in the internal iliac vein. | 1,709 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
True pelvis, pelvic floor and perineum
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The perineal tributaries receive veins from the penile bulb and the Perineal nerve
scrotum (males), or clitoris and labia (females), and the inferior rectal
veins join towards the posterior end of the pudendal canal.
The perineal nerve is the inferior and larger terminal branch of the
pudendal nerve in the pudendal canal. It runs forwards below the
Lymphatic drainage of the perineum
internal pudendal artery and accompanies the perineal artery, dividing
into posterior scrotal or labial and muscular branches. The posterior
The lymphatics from the skin of the penis and scrotum (male), or skin scrotal or labial nerves are usually double; they have medial and lateral
of the clitoris and labia (female), drain together with lymphatics from branches that run over the perineal membrane and pass forwards in the
the perineal skin to the superficial inguinal nodes and, from there, to lateral part of the urogenital triangle with the scrotal or labial branches
the deep inguinal nodes. The glans, corpora cavernosa and corpus of the perineal artery. They supply the skin of the scrotum or labia
spongiosum of the penis or clitoris drain directly to the deep inguinal majora, overlapping the distribution of the perineal branch of the pos-
nodes (see Fig. 78.10). terior femoral cutaneous and inferior rectal nerves. In females, the
posterior labial branches also supply sensory fibres to the skin of the
lower vagina.
INNERVATION OF THE PERINEUM: PUDENDAL
Muscular branches arise directly from the pudendal nerve to supply
NERVE (IN THE PERINEUM) the superficial transverse perineal muscles, bulbospongiosus, ischiocav-
ernosus, sphincter urethrae and the anterior parts of the external anal
The pudendal nerve gives rise to the inferior rectal and perineal nerves sphincter and levator ani. In males, a nerve to the bulb of the urethra
and to the dorsal nerves of the penis or clitoris. The course of its leaves the nerve to the bulbospongiosus, pierces this muscle to supply
branches parallels the pudendal vessels (see Figs 76.24, 77.4). The the corpus spongiosum penis, and ends in the urethral mucosa.
pudendal nerve occupies a very constant position over the ischial spine
and is readily found. It may be ‘blocked’ by infiltration with a local Dorsal nerve of the penis or clitoris
anaesthetic applied via a needle passed through the lateral wall of the
vagina to numb the perineal and anal skin. It may also be palpated over The dorsal nerve of the penis or clitoris runs anteriorly above the inter-
the ischial spine through the lateral wall of the rectum and motor ter- nal pudendal artery along the ischiopubic ramus, deep to the perineal
minal latencies may be measured. membrane. It supplies the corpus cavernosum and accompanies the
dorsal artery of the penis or clitoris between the layers of the suspensory
Inferior rectal nerve ligament. In males, the dorsal nerve of the penis runs on the dorsum
of the penis to end in the glans.
The inferior rectal nerve runs through the medial wall of the pudendal
canal with the inferior rectal vessels. It crosses the ischio-anal fossa to
supply the external anal sphincter, the lining of the lower part of
Bonus e-book images
the anal canal and the circumanal skin. It frequently breaks into termi-
nal branches before reaching the lateral border of the sphincter. Its
cutaneous branches that are distributed around the anus overlap the
cutaneous branches of the perineal branch of the posterior femoral Fig. 73.7 The relationship between anteroposterior diameters of the
right common, internal and external iliac arteries and body surface
cutaneous nerve and of the scrotal or labial nerves. The inferior rectal
area (BSA) in boys and girls between the ages of 1 and 16 years.
nerve occasionally arises directly from the sacral plexus and crosses the
sacrospinous ligament or reconnects with the pudendal nerve. In
females, the inferior rectal nerve may supply sensory branches to the
lower part of the vagina.
KEY REFERENCES
Dalley AF 1987 The riddle of the sphincters. Am Surg 53:298. This study, along with its companion article concerning the male urethral
A review of the anatomy of the external anal sphincter that brings clarity to sphincter anatomy, dispelled the longstanding errors surrounding a
the discussion of controversial and competing concepts. ‘urogenital diaphragm’ and corrected the anatomy of the urethral sphincter.
Huisman AB 1983 Aspects on the anatomy of the female urethra with Reiffenstuhl G 1982 The clinical significance of the connective tissue planes
special relation to urinary continence. Contrib Gynecol Obstet 10:1. and spaces. Clin Obstet Gynecol 25:811.
A detailed and comprehensive account of the anatomy of the urethra based The complex 3-dimensional network of the pelvic connective tissues has been
on histological examination. confusing to many; this clearly illustrated article shows the different
elements of the pelvic fasciae.
Klink EW 1953 Perineal nerve block: an anatomic and clinical study in the
female. Obstet Gynecol 1:137. Ricci JV, Lisa JR, Thom CH, et al 1947 The relationship of the vagina to
Lawson JO 1974a Pelvic anatomy. I. Pelvic floor muscles. Ann R Coll Surg adjacent organs in reconstructive surgery. Am J Surg 74:387.
Engl 54:244. A great deal has been written about the ‘fascia’ of the female pelvis as it
An objective evaluation of the anatomy of levator ani based on serial relates to the problem of pelvic organ prolapse. Ricci’s approach, using
histological sections. whole-pelvic cross-sectional anatomy, brings clarity to this discussion.
Nesselrod JP 1936 An anatomic restudy of the pelvic lymphatics. Ann Surg Roberts WH, Krishingner GL 1967 Comparative study of human internal
104:905. iliac artery based on Adachi classification. Anat Rec 158:191.
An account of the importance of the pelvic lymphatic system in tumour A description of the considerable variation in the anatomy of the internal
spread and treatment that provides an accurate description of its component iliac artery.
parts. Tobin CE, Benjamin JA 1949 Anatomic and clinical re-evaluation of
Oelrich TM 1980 The urethral sphincter muscle in the male. Am J Anat Camper’s, Scarpa’s and Colles’ fasciae. Surg Gynecol Obstet 88:545.
158:229–46. A description of the anatomy of Camper’s, Scarpa’s and Colles’ fasciae that
See comments for Oelrich 1983. clarifies understanding of these structures, which are often poorly described
or incorrectly illustrated.
Oelrich TM 1983 The striated urogenital sphincter muscle in the female.
Anat Rec 205:223. | 1,710 | 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
Campbell RM 1950 The anatomy and histology of the sacrouterine liga- Oelrich TM 1980 The urethral sphincter muscle in the male. Am J Anat
ments. Am J Obstet Gynecol 59:1. 158:229–46.
Dalley AF 1987 The riddle of the sphincters. Am Surg 53:298. See comments for Oelrich 1983.
A review of the anatomy of the external anal sphincter that brings clarity to Oelrich TM 1983 The striated urogenital sphincter muscle in the female.
the discussion of controversial and competing concepts. Anat Rec 205:223.
DeLancey JO 1992 Anatomic aspects of vaginal eversion after hysterectomy. This study, along with its companion article concerning the male urethral
Am J Obstet Gynecol 166:1717. sphincter anatomy, dispelled the longstanding errors surrounding a
‘urogenital diaphragm’ and corrected the anatomy of the urethral sphincter.
DeLancey JO 1994 Structural support of the urethra as it relates to stress
urinary incontinence: the hammock hypothesis. Am J Obstet Gynecol Oh C, Kark AE 1972 Anatomy of the external anal sphincter. Br J Surg
170:1713–23. 59:717.
DeLancey JO, Trowbridge ER, Miller JM et al 2008 Stress urinary inconti- Oh C, Kark AE 1973 Anatomy of the perineal body. Dis Colon Rectum
nence: relative importance of urethral support and urethral closure 16:444.
pressure. J Urol 179:2286–90. Range RL,Woodburne RT 1964 The gross and microscopic anatomy of the
de la Portilla F, López-Alonso M 2009 Endosonography of the anal canal: transverse cervical ligaments. Am J Obstet Gynecol 90:460.
findings in children. Dis Colon Rectum 52:711–4. Rehman Y, Stensrud KJ, Morkrid L et al 2011 Endosonographic evaluation
Dogan R, Dogan OF, Oc M et al 2003 A rare vascular malformation, Klippel- of anal sphincters in healthy children. J Pediatr Surg 46:1587–92.
Trenaunay syndrome. Report of a case with deep vein agenesis and Reiffenstuhl G 1982 The clinical significance of the connective tissue planes
review of the literature. J Cardiovasc Surg 44:95–100. and spaces. Clin Obstet Gynecol 25:811.
Doyle JF 1970 The perforating veins of the gluteus maximus. Ir J Med Sci The complex 3-dimensional network of the pelvic connective tissues has been
3:285–8. confusing to many; this clearly illustrated article shows the different
Emans JB, Ciarlo M, Callahan M et al 2005 Prediction of thoracic dimen- elements of the pelvic fasciae.
sions and spine length based on individual pelvic dimensions in chil- Ricci JV, Lisa JR, Thom CH, et al 1947 The relationship of the vagina to
dren and adolescents: an age-independent, individualized standard for adjacent organs in reconstructive surgery. Am J Surg 74:387.
evaluation of outcome in early onset spinal deformity. Spine 30: A great deal has been written about the ‘fascia’ of the female pelvis as it
2824–9. relates to the problem of pelvic organ prolapse. Ricci’s approach, using
Gupta NP, Kumar M, Karan SC et al 1999 Lower ureteral obstruction due to whole-pelvic cross-sectional anatomy, brings clarity to this discussion.
a persistent umbilical artery. Urol Int 63:249–51.
Roberts WH, Krishingner GL 1967 Comparative study of human internal
Huisman AB 1983 Aspects on the anatomy of the female urethra iliac artery based on Adachi classification. Anat Rec 158:191.
with special relation to urinary continence. Contrib Gynecol Obstet A description of the considerable variation in the anatomy of the internal
10:1. iliac artery.
A detailed and comprehensive account of the anatomy of the urethra based
on histological examination. Roberts WH, Habenicht J, Krishingner G 1964 The pelvic and perineal
fasciae and their neural and vascular relationships. Anat Rec 149:707.
Kakizaki H, Moriya K, Ameda K et al 2003 Diameter of the external urethral
Roberts WH, Harrison CW, Mitchell DA et al 1988 The levator ani muscle
sphincter as a predictor of detrusor-sphincter incoordination in chil-
and the nerve supply of its puborectalis component. Clin Anat 1:256.
dren: comparative study of voiding cystourethrography. J Urol 169:
655–8. Sato K 1980 Amorphological analysis of the nerve supply of the sphincter
ani externus, levator ani and coccygeus. Acta Anat Nippon 44:187.
Klink EW 1953 Perineal nerve block: an anatomic and clinical study in the
female. Obstet Gynecol 1:137. Stein TA, DeLancey JO 2008 Structure of the perineal membrane in females:
gross and microscopic anatomy. Obstet Gynecol 111:686–93.
Lawson JO 1974a Pelvic anatomy. I. Pelvic floor muscles. Ann R Coll Surg
Engl 54:244. Tobin CE, Benjamin JA 1949 Anatomic and clinical re-evaluation of
An objective evaluation of the anatomy of levator ani based on serial Camper’s, Scarpa’s and Colles’ fasciae. Surg Gynecol Obstet 88:545.
histological sections. A description of the anatomy of Camper’s, Scarpa’s and Colles’ fasciae that
clarifies understanding of these structures, which are often poorly described
Lawson JO 1974b Pelvic anatomy. II. Anal canal and associated sphincters. or incorrectly illustrated.
Ann R Coll Surg Engl 54:288.
Wendell-Smith CP, Wilson PM 1991 The vulva, vagina and urethra and the
Munk A, Darge K, Wiesel M et al 2002 Diameter of the infrarenal aorta and
musculature of the pelvic floor. In: Philipp E, Setchell M, Ginsburg J
the iliac arteries in children: ultrasound measurements. Transplantation
(eds) Scientific Foundations of Obstetrics and Gynaecology. Oxford:
73:631–5.
Butterworth–Heinemann, pp. 84–100.
Nesselrod JP 1936 An anatomic restudy of the pelvic lymphatics. Ann Surg
104:905.
An account of the importance of the pelvic lymphatic system in tumour
spread and treatment that provides an accurate description of its component
parts. | 1,711 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
CHAPTER
74
Kidney and ureter
and narrower than the right and lies nearer the median plane (Fig.
KIDNEY
74.1). The long axis of each kidney is directed inferolaterally and the
transverse axis posteromedially, which means that the anterior and
The kidneys excrete end-products of metabolism and excess water. posterior aspects usually described are, in fact, anterolateral and pos-
These actions are essential for the control of concentrations of various teromedial. An appreciation of this orientation is important in percu-
substances in the body, maintaining electrolyte and water balance taneous and endo-urological renal surgery.
approximately constant in the tissue fluids. The kidneys also have In adults, each kidney is typically 11 cm in length, 6 cm in breadth
endocrine functions, producing and releasing erythropoietin, which and 3 cm in anteroposterior dimension. The left kidney may be 1.5 cm
affects red blood cell formation; renin, which influences blood pres- longer than the right; it is rare for the right kidney to be more than
sure; 1,25-di-hydroxycholecalciferol (the metabolically active form of 1 cm longer than the left. The average weight is 150 g in men and 135 g
vitamin D), which is involved in the control of calcium absorption and in women. In thin individuals with a lax abdominal wall, the lower
mineral metabolism; and various other soluble factors with metabolic pole of the lower right kidney may just be felt in full inspiration by
actions. bimanual lumbar examination, but this is unusual. In the fetus and the
In the fresh state, the kidneys are reddish-brown. They are situated newborn, the kidney normally has 12 lobules; in the adult, these
posteriorly behind the peritoneum, on each side of the vertebral lobules are fused to present a smooth surface, although traces of lobula-
column, and are surrounded by adipose tissue. Superiorly, they are level tion may remain and can mimic a renal mass on radiographic imaging.
with the upper border of the twelfth thoracic vertebra, and inferiorly,
with the third lumbar vertebra. The right is usually slightly inferior to Absent and ectopic kidneys A single absent kidney, resulting
the left, reflecting its relationship to the liver. The left is a little longer from the failure of the metanephric blastema to join a ureteric bud on
Stomach, cardia
Coeliac trunk
Hepatic artery proper
Hepatic portal vein Left suprarenal gland
Suprarenal gland
Splenic artery and vein
Bile duct
Inferior mesenteric vein
Superior mesenteric
artery and vein
Duodenum, descending part
Head of pancreas,
Left kidney
uncinate process
Ureter
Abdominal aorta
Left colic artery
Inferior vena cava
Testicular artery and vein
Inferior mesenteric artery and vein
Common iliac artery Superior rectal artery
and vein Sigmoid arteries and veins
Femoral nerve
Sigmoid colon
External iliac artery and vein
Urinary bladder
Inferior epigastric artery
and vein
Fig. 74.1 Relationships of the kidneys and ureters in the male retroperitoneum. (With permission from Waschke J, Paulsen F (eds), Sobotta Atlas of
Human Anatomy, 15th ed, Elsevier, Urban and Fischer. Copyright 2013.) 1237 | 1,712 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
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the affected side, is seen in 1 in 1200 individuals. There are no clinical cal development. The ureters curve anterior to the isthmus and often
sequelae, but the ipsilateral vas (ductus) deferens and/or epididymis have a high insertion into the renal pelvis (Fig. 74.3).
may also be absent and there may be other congenital anomalies, The blood supply to horseshoe kidneys is variable. One vessel to
including imperforate anus, cardiac valvular anomalies and oesopha- each moiety is seen in 30% of horseshoe kidneys but multiple anoma-
geal atresia. A single kidney often shows compensatory hypertrophy lous vessels are common; the isthmus may be supplied by a vessel
but, provided the single kidney is anatomically and functionally directly from the aorta or from branches of the inferior mesenteric,
normal, the life expectancy of individuals with a single kidney is no common iliac or external iliac arteries. In view of this variable arterial
different from that of those with two kidneys. anatomy, angiography or computed tomography (CT) scanning with
Failure of the kidney to ascend into the renal fossa in utero results vascular reconstruction is very helpful when planning renal surgery on
in renal ectopia. An ectopic kidney is found in the pelvis in 1 in 2500 horseshoe kidneys. Horseshoe kidneys may exhibit an associated con-
live births. Kidneys so placed often have associated malrotation anoma- genital ureteropelvic junction obstruction in up to 30% of cases and
lies and may have marked fetal lobulation. Pelvic kidneys frequently have a chromosomal anomaly in 56% of cases (Scott 2002). Anoma-
become hydronephrotic as a result of an anteriorly placed ureter and lous vessels crossing the ureter, and the abnormal course of the ureter
an anomalous arterial supply; an associated ureteropelvic junction as it passes over renal substance, may also cause obstruction.
obstruction is often present.
Very rarely, and despite the normal location of the ureteric orifices
within the bladder, the two kidneys may be on the same side (crossed PERIRENAL FASCIA
renal ectopia) and are usually fused (crossed-fused ectopia). A solitary
crossed renal ectopia may be associated with skeletal and other geni- The perirenal fascia, sometimes referred to as Gerota’s fascia (p. 1084),
tourinary anomalies. A number of different anatomical patterns can is a dense, elastic connective tissue sheath that envelops each kidney
result, all of which are extremely rare (Fig. 74.2). and suprarenal gland, together with a layer of surrounding perirenal fat
(Fig. 74.4; see Fig. 62.2). The kidney and its vessels are embedded in
Horseshoe kidney Horseshoe kidneys are found in 1 in 400 indi- perirenal fat, which is thickest at the renal borders and extends into the
viduals. A transverse bridge of renal tissue, the isthmus, often contain- renal sinus at the hilum.
ing functioning renal substance, connects the two renal masses. The The perirenal fascia was originally described as being made up of
isthmus lies between the inferior poles, most commonly anterior to the two separate entities, the posterior fascia of Zuckerkandl and the ante-
great vessels; it is often inferior to the inferior mesenteric artery because rior fascia of Gerota, which fused laterally to form the lateroconal fascia
this vessel obstructs the normal ascent of the kidney during embryologi- (Burkhill and Healy 2000). According to this view, the lateroconal fascia
A B C
Unilateral fused kidney Unilateral fused kidney Sigmoid or S-shaped kidney
(inferior ectopia) (superior ectopia)
D E F
Lump kidney L-shaped kidney Disc kidney
Fig. 74.2 Crossed renal ectopia: the possible arrangements of crossed ectopic kidneys. | 1,713 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney
1239
47
retPaHC
A A
Renal veins; renal artery Eleventh rib
Twelfth rib
Liver
Posterior lamina Anterior lamina
of renal fascia of renal (Gerota’s)
fascia
Peritoneum
Vessel of
renal hilum
Right colic
Right ureter Left ureter flexure
B
Rectus abdominis
External oblique
Internal oblique
Transversus
abdominis
Fascia
transversalis
B
Peritoneum
Colon
Anterior
lamina of
renal fascia
Kidney
Perirenal fat
Quadratus lumborum
Psoas major Erector spinae
Fig. 74.4 A, A sagittal section through the posterior abdominal wall,
showing the relations of the renal fascia of the right kidney. B, A
transverse section, showing the relations of the renal fascia.
which, at a variable point, divides into a thin anterior lamina, passing
C anterior to the kidney as the anterior perirenal fascia, and a thicker
posterior lamina that continues anterolaterally as the lateroconal fascia
Fig. 74.3 A, A horseshoe kidney. Note the ureters pass anterior to the and fuses with the parietal peritoneum.
isthmus, and the relatively high insertion of the ureters into the renal Classically, the anterior perirenal fascia was thought to blend into
pelvis. B, Axial contrast-enhanced computed tomography (CT) image. the dense mass of connective tissue surrounding the great vessels in the
C, Coronal maximal intensity projection (MIP) image of the abdomen. root of the mesentery behind the duodenum and pancreas, thereby
B and C demonstrate midline connection of the parenchyma of the two preventing communication between perirenal spaces across the midline.
kidneys below the inferior mesenteric artery (B, arrow), in a horseshoe However inspection of CT images or of anatomical sections of cadavers,
configuration, in keeping with a horseshoe kidney. (A, With permission following injection of contrast or coloured latex, respectively, into the
from Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, perirenal space, revealed that fluid could extend across the midline at
15th ed, Elsevier, Urban and Fischer. Copyright 2013.) the third to fifth lumbar levels through a narrow channel measuring
2–10 mm in anteroposterior dimension. In the midline superiorly, the
anterior and posterior renal fasciae fuse and are attached to the crura
continued anterolaterally behind the colon to blend with the parietal of their respective hemidiaphragms. Inferiorly, the fasciae separate for
peritoneum. However, work by Mitchell (1950) showed that the peri- a variable craniocaudal distance. The posterior perirenal fascia fuses
renal fascia is not made up of distinct fused fasciae but is, in fact, a with the muscular fascia of psoas major, while the anterior perirenal
single multilaminated structure that is fused posteromedially with the fascia extends across the midline anterior to the great vessels; commu-
muscular fasciae of psoas major and quadratus lumborum. It then nication between the two sides is permitted, although is very rarely of
extends anterolaterally behind the kidney as a bilaminated sheet, clinical significance. Below this level, the two fasciae once again merge | 1,714 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
1240
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nOitCeS
and are attached to the great vessels or iliac vessels. The containment A
of fluid to one side of the perirenal space that is observed in over two-
thirds of clinical cases is attributed to the presence of fibrous septa. Superior Perinephric fat
Above the suprarenal glands, the anterior and posterior perirenal suprarenal arteries Fibrous capsule
fasciae were previously said to fuse with each other and to the diaphragm-
atic fascia. This description of a closed superior cone is not universally
Middle
accepted. Cadaveric experiments have shown the superior aspect of the suprarenal
perirenal space to be open and in continuity with the bare area of the arteries
liver on the right and the subphrenic extraperitoneal space on the left.
The posterior fascial layer blends bilaterally with the fascia of psoas Suprarenal gland
major and quadratus lumborum, as well as the inferior phrenic fascia. Suprarenal vein
The anterior fascial layer on the right blends with the right inferior
Inferior suprarenal
coronary ligament at the level of the upper pole of the kidney and bare
artery
area of the liver. On the left, the anterior layer fuses with the gastro-
splenic ligament at the level of the suprarenal gland. Renal artery,
There is some debate concerning the inferior fusion of the perirenal posterior branch
fascia. Many investigators believe that, inferiorly, the anterior and pos-
terior leaves of the perirenal fascial fuse to produce an inverted cone Renal vein
that is open to the pelvis at its apex. Laterally, the anterior and posterior
Hilum of kidney Renal
leaves fuse with the iliac fascia; medially, they fuse with the periureteric
Renal artery, pelvis
connective tissue. The inferior apex of the cone is open anatomically
anterior branch
towards the iliac fossa but rapidly becomes sealed in inflammatory
Left testicular/ovarian
disease. An alternative view is based on the dissection of recently
vein
deceased cadavers after injections of coloured latex into the perirenal
Ureter
space, which have shown that the anterior and posterior perirenal
fasciae merge to form a single multilaminar fascia that contains the
ureter in the iliac fossa. Anteriorly, this common fascia is loosely con-
nected to the parietal peritoneum, and so denies free communication
between the perirenal space and the pelvis, and between the perirenal
and pararenal spaces.
A simple nephrectomy for benign disease removes the kidney from B
within perirenal fascia; a radical nephrectomy (for cancer) classically Superior suprarenal arteries
removes the entire contents of the perirenal space, including the peri-
renal fascia and suprarenal gland, in order to give adequate clearance
around the tumour.
Superior border
Suprarenal gland
RELATIONS
Suprarenal gland, hilum
Middle suprarenal
The superior poles of both kidneys are thick and round, and related to Perinephric fat arteries
their respective suprarenal glands (Fig. 74.5). The inferior poles are Suprarenal veins
Fibrous capsule
thinner and extend to within 2.5 cm of the iliac crests. The lateral
borders are convex. The medial borders are convex adjacent to the poles
Medial border
and concave between them, and slope inferolaterally. In each, a deep
vertical fissure opens anteromedially as the hilum, which is bounded
by anterior and posterior lips and contains the renal vessels and nerves,
and the renal pelvis. The relative positions of the main hilar structures
are the renal vein (anterior), the renal artery (intermediate) and the Inferior suprarenal artery
pelvis of the kidney (posterior) (Fig. 74.6). Usually, an arterial branch
from the main renal artery runs over the superior margin of the renal
pelvis to enter the hilum on the posterior aspect of the pelvis, and a Renal artery
renal venous tributary often leaves the hilum in the same plane. Above
the hilum, the medial border is related to the suprarenal gland and
below to the origin of the ureter. Renal vein
The convex anterior surface of the kidney actually faces anterolater- Hilum of kidney
ally and its relations differ on the right and left. Likewise, the posterior
surface of the kidneys, in reality, faces posteromedially. Its relations are
Ureter
similar on both sides of the body (Fig. 74.7).
A small area of the superior pole of the right kidney is in contact with
the right suprarenal gland, which may overlap the upper part of the
medial border of the superior pole (Fig. 74.8). A large area below this is
immediately related to the right lobe of the liver, separated by a layer of
peritoneum. A narrow medial area is directly related to the retroperito-
neal descending part of the duodenum. Inferiorly, the anterior surface is
directly in contact laterally with the retroperitoneal right colic flexure
and medially with part of the intraperitoneal small intestine.
A small medial area of the superior pole of the left kidney is related Fig. 74.5 A, The posterior aspect of the left kidney and suprarenal gland.
to the left suprarenal gland (see Fig. 74.8). The lateral half of the ante- B, The posterior aspect of the right kidney and suprarenal gland. Note
rior surface is related to the spleen, from which it is separated by a layer that the left suprarenal vein enters the left renal vein. This is an important
of peritoneum. A central quadrilateral area lies in direct contact with relationship to identify when performing a left nephrectomy. (With
the retroperitoneal pancreas and the splenic vessels. Above this, a small, permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human
variable, triangular region, between the suprarenal and splenic areas, is Anatomy, 15th ed, Elsevier, Urban and Fischer. Copyright 2013.)
in contact with the stomach, separated by a layer of peritoneum. Below
the pancreatic and splenic areas, a narrow lateral strip that extends to of the greater sac. Behind the peritoneum covering the jejunal area,
the lateral border of the kidney is directly related to the retroperitoneal branches of the left colic vessels are related to the kidney.
left colic flexure and the beginning of the descending colon. An exten- The posteromedial surface of the kidneys is embedded in fat and
sive medial area is related to intraperitoneal loops of jejunum. The devoid of peritoneum. The right and left kidneys are related to similar
gastric area is covered with the peritoneum of the lesser sac (omental structures. Superiorly are the diaphragm and the medial and lateral
bursa), and the splenic and jejunal areas are covered by the peritoneum arcuate ligaments. More inferiorly, moving in a medial to lateral | 1,715 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney
1241
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retPaHC
direction, are psoas major, quadratus lumborum and the aponeurotic INTERNAL MACROSTRUCTURE
tendon of transversus abdominis, the subcostal vessels, and the subcos-
tal, iliohypogastric and ilioinguinal nerves. The upper pole of the right The postnatal kidney has a thin fibrous capsule composed of collagen-
kidney is level with the twelfth rib, and that of the left with the eleventh rich connective tissue with some elastic and smooth muscle fibres. In
and twelfth ribs. The diaphragm separates the kidney from the pleura, renal disease, the capsule may become adherent.
which descends to form the costodiaphragmatic recess; diaphragmatic The kidney itself can be divided into an internal medulla and
muscle is sometimes defective or absent in a triangle immediately above external cortex (Fig. 74.9). The renal medulla consists of pale, striated,
the lateral arcuate ligament, and this allows perirenal adipose tissue to conical renal pyramids; their bases are peripheral, and their apices
contact the diaphragmatic pleura. converge to the renal sinus. At the renal sinus, they project into calyces
as papillae.
The renal cortex (see Fig. 74.14) is subcapsular, arching over the
bases of the pyramids and extending between them towards the renal
sinus as renal columns. Its peripheral regions are termed cortical arches
and are traversed by radial, lighter-coloured, medullary rays, separated
by darker tissue, the convoluted part. The rays taper towards the renal
capsule and are peripheral prolongations from the bases of renal pyra-
mids. The cortex is histologically divisible into outer and inner zones.
The inner zone is demarcated from the medulla by tangential blood
RA
vessels (arcuate arteries and veins), which lie at the junction of the two;
however, a thin layer of cortical tissue (subcortex) appears on the med-
ullary side of this zone. The cortex close to the medulla is sometimes
RV termed the juxtamedullar cortex.
Renal pelvis and calyces
Fig. 74.6 An intraoperative view of the dissected renal hilum. The kidney The hilum of the kidney leads into a central renal sinus, lined by the
is seen enveloped by Gerota’s fascia in the superior aspect of the renal capsule and almost filled by the renal pelvis and vessels; the
operative field. The renal artery (RA) is noted in its posterior location remaining space is filled by fat. Dissection into this plane can be chal-
adjacent to the larger renal vein (RV). lenging but is important in surgery on the renal pelvis, particularly open
Gallbladder Superior mesenteric vein Superior mesenteric artery Spleen Stomach Pancreas
C
Duodenum Left kidney
A Liver Gallbladder
Liver Head of pancreas Left renal vein Left kidney Spleen
Liver Right kidney Right suprarenal gland Left suprarenal gland Spleen
B D
Left psoas major Left kidney Right hepatic flexure Duodenum Right kidney
Fig. 74.7 Multislice CT scans of the kidneys. A, An axial CT scan of the kidneys showing the anatomical relationships of the kidneys at the renal hilum.
B, A coronal reformat showing both kidneys and the suprarenal glands. C, A sagittal reformat of the left kidney lying posterior to the stomach, spleen
and pancreas. D, A sagittal reformat of the right kidney lying posterior to the right lobe of the liver, hepatic flexure and duodenum. | 1,716 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
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Right Left Stomach
B Left Right
A Right suprarenal gland Left suprarenal gland Spleen
Pancreas Eleventh rib
Liver Left colic
flexure
Descending part
Descending
of duodenum
colon
Right colic
flexure
Jejunum
Twelfth rib
Psoas major
Small intestine
Quadratus lumborum
Transversus abdominis
Fig. 74.8 The surfaces of the kidneys. A, Anterior, showing the areas related to neighbouring viscera. The areas where overlying viscera are separated
from the kidney by peritoneum are shown. B, Posterior, showing the areas of relation to the posterior abdominal wall. (With permission from Drake RL,
Vogl AW, Mitchell A, Tibbitts R, Richardson P (eds), Gray’s Atlas of Anatomy, Elsevier, Churchill Livingstone. Copyright 2008.)
A B
Renal cortex
Renal column
Renal medulla,
Branch of renal artery
renal pyramids
Fibrous capsule
Major calyces Interlobar
arteries
Renal artery
Pelvis of kidney Minor calyces Cribriform area, openings
of papillary ducts
Renal vein
Margin of hilum Renal sinus, fat body
Pyramid in
renal medulla
Renal sinus Renal pelvis
Ureter
Ureter Base of pyramid
Arcuate artery
Renal papilla
Fig. 74.9 The left kidney, oblique vertical hemisection: normal macroscopic appearance of the renal cortex and renal medulla, and the major structures
at the hilum of the kidney. A, The fat body of the renal sinus and most of the major vessels at the hilum have been removed, and the renal pelvis has not
been opened. B, The renal pelvis has been opened to reveal the interlobar arteries. (B, With permission from Waschke J, Paulsen F (eds), Sobotta Atlas
of Human Anatomy, 15th ed, Elsevier, Urban and Fischer. Copyright 2013.)
stone surgery. Within the renal sinus, the collecting tubules of the extrarenal. The funnel-shaped renal pelvis tapers as it passes infero-
nephrons of the kidney open on to the summits of the renal papillae medially, traversing the renal hilum to become continuous with the
to drain into minor calyces, which are funnel-shaped expansions of the ureter (see Figs 74.9–74.10). It is rarely possible to determine precisely
upper urinary tract. The renal capsule covers the external surface of the where the renal pelvis ceases and the ureter begins; the region is usually
kidney and continues through the hilum to line the sinus and fuse with extrahilar and normally lies adjacent to the lower part of the medial
the adventitial coverings of the minor calyces. Each minor calyx sur- border of the kidney. Rarely, the entire renal pelvis has been found to
rounds either a single papilla or, more rarely, groups of two or three lie inside the sinus of the kidney so that the pelviureteric region occurs
papillae. The minor calyces unite with their neighbours to form two, or either in the vicinity of the renal hilum or completely within the renal
possibly three, larger chambers: the major calyces. There is wide varia- sinus.
tion in the arrangement of the calyces. As the posterior aspect of the The calyces, renal pelvis and ureter are well demonstrated radiologi-
kidney rotates laterally during its ascent in utero, the calyces that were cally following an intravenous injection of radio-opaque contrast that
lateral in utero become positioned anteriorly, and the medial calyces is excreted in the urine (computed tomographic urography, CTU) (Fig.
move more posteriorly. The calyces drain into the infundibula. The 74.10), or after the introduction of radio-opaque contrast into the
renal pelvis is normally formed from the junction of two infundibula ureter by catheterization through a cystoscope (ascending or retrograde
– one from the upper and one from the lower pole calyces – but there pyelography). Normal cupping of the minor calyces by projecting renal
may be a third, which drains the calyces in the mid portion of the papillae may be obliterated by conditions that cause hydronephrosis:
kidney. The calyces are usually grouped so that three pairs drain into chronic distension of the ureter and renal pelvis due to upper or lower
the upper pole infundibulum and four pairs into the lower pole urinary tract obstruction, resulting in elevated intrapelvic pressure. An
infundibulum. If there is a middle infundibulum, the distribution is appreciation of the rotation of the kidneys, which results in the poste-
normally three pairs at the upper pole, two in the middle, and two at rior calyces lying relatively medially and the anterior calyces lying later-
the lower pole. There is considerable variation in the arrangement of ally, is essential when interpreting contrast imaging of the collecting
the infundibula and in the extent to which the pelvis is intrarenal or system of the kidneys. | 1,717 | 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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retPaHC
Pelvis of kidney Fig. 74.10 A 39-year- (Schneider et al 2013). Rarely, accessory renal arteries arise from the
old man with a history coeliac or superior mesenteric arteries near the aortic bifurcation, or
of intrinsic sphincter from the common iliac arteries.
deficiency: coronal The subdivisions of the renal arteries are described sequentially as
CT urogram. A, A segmental, lobar, interlobar, arcuate and interlobular arteries, and affer-
maximum-intensity ent and efferent glomerular arterioles (Fig. 74.14).
projection (MIP).
B, A volume-rendered Segmental arteries
image. Both images Renal vascular segmentation was originally recognized by John Hunter
demonstrate collecting in 1794, but the first detailed account of the primary pattern was pro-
systems, ureters and
duced in the 1950s from casts and radiographs of injected kidneys. Five
bladder that appear
arterial segments have been identified (Fig. 74.15). The apical segment
normal.
occupies the anteromedial region of the superior pole. The superior
(anterior) segment includes the rest of the superior pole and the central
anterosuperior region. The inferior segment encompasses the whole
lower pole. The middle (anterior) segment lies between the anterior and
inferior segments. The posterior segment includes the whole posterior
A
region between the apical and inferior segments. This is the pattern
most commonly seen, and although there can be considerable varia-
Bladder ureter tion, it is the pattern that clinicians most frequently encounter when
performing partial nephrectomy. Whatever pattern is present, it is
important to emphasize that vascular segments are supplied by virtual
end arteries. In contrast, larger intrarenal veins have no segmental
organization and anastomose freely.
Brödel described a relatively avascular longitudinal zone (the ‘blood-
less’ line of Brödel) along the convex renal border, which was proposed
as the most suitable site for surgical incision (Brödel 1911). However,
many vessels cross this zone, and it is far from ‘bloodless’; planned
radial or intersegmental incisions are preferable. Knowledge of the
vascular anatomy of the kidney is important when undertaking partial
nephrectomy for renal cell cancers. In this surgery, the branches of the
renal artery are defined so that the surgeon may safely excise the renal
substance containing the tumour while not compromising the vascular
supply to the remaining renal tissue (Novick 1998).
Lobar, interlobar, arcuate
and interlobular arteries
The initial branches of segmental arteries are lobar, usually one to each
renal pyramid. Before reaching the pyramid, they subdivide into two or
three interlobar arteries, extending towards the cortex around each
pyramid. At the junction of the cortex and medulla, interlobar arteries
dichotomize into arcuate arteries, which diverge at right angles. As they
B arch between cortex and medulla, each divides further, ultimately sup-
plying interlobular arteries that diverge radially into the cortex. The ter-
minations of adjacent arcuate arteries do not anastomose but end in the
cortex as additional interlobular arteries. Though most interlobular arter-
VASCULAR SUPPLY AND LYMPHATIC DRAINAGE
ies come from arcuate branches, some arise directly from arcuate, or even
terminal, interlobar arteries (see Fig. 74.14). Interlobular arteries ascend
Renal arteries towards the superficial cortex or may branch occasionally en route. Some
are more tortuous and recurve towards the medulla at least once before
The paired renal arteries take about 20% of the cardiac output to supply proceeding towards the renal surface. Others traverse the surface as per-
organs that represent less than 1% of total body weight. They branch forating arteries to anastomose with the capsular plexus (which is also
laterally from the aorta just below the origin of the superior mesenteric supplied from the inferior suprarenal, renal and gonadal arteries).
artery (see Fig. 59.6; Fig. 74.11A). Both cross the corresponding crus of
the diaphragm at right angles to the aorta. The right renal artery is afferent and efferent glomerular arterioles
longer and often higher, passing posterior to the inferior vena cava, right Afferent glomerular arterioles are mainly the lateral rami of interlobular
renal vein, head of the pancreas, and descending part of the duodenum. arteries. A few arise from arcuate and interlobar arteries, when they vary
The left renal artery is a little lower and passes behind the left renal their direction and angle of origin: deeper ones incline obliquely back
vein, the body of the pancreas, and splenic vein. It may be crossed towards the medulla, the intermediate pass horizontally, and the more
anteriorly by the inferior mesenteric vein. superficial approach the renal surface obliquely before ending in a
A single renal artery to each kidney is present in approximately 70% glomerulus (see Fig. 74.14). Efferent glomerular arterioles from most
of individuals (Fig. 74.12). The arteries vary in their level of origin and glomeruli (except at juxtamedullary and, sometimes, at intermediate
in their calibre, obliquity and precise relations (Fig. 74.11B). In its cortical levels) soon divide to form a dense peritubular capillary plexus
extrarenal course, each renal artery gives off one or more inferior supra- around the proximal and distal convoluted tubules; there are, thus, two
renal arteries, a branch to the ureter, and branches that supply peri- sets of capillaries – glomerular and peritubular – in series in the main
nephric tissue, the renal capsule and the pelvis. Near the renal hilum, renal cortical circulation, linked by efferent glomerular arterioles. The
each artery divides into an anterior and a posterior division, and these vascular supply of the renal medulla is largely from efferent arterioles
divide into segmental arteries supplying the renal vascular segments of juxtamedullary glomeruli, supplemented by some from more super-
(Fig. 74.11C). Accessory renal arteries are common (30% of individu- ficial glomeruli, and ‘aglomerular’ arterioles (probably from degener-
als), and usually arise from the aorta above or below (most commonly, ated glomeruli). Efferent glomerular arterioles passing into the medulla
below) the main renal artery and follow it to the renal hilum (Merklin are relatively long, wide vessels, and contribute side branches to neigh-
and Michels 1958). They are regarded as persistent embryonic lateral bouring capillary plexuses before entering the medulla, where each
splanchnic arteries. Accessory vessels to the inferior pole cross anterior divides into 12–25 descending vasa recta. As their name suggests, these
to the ureter and may, by obstructing the ureter, cause hydronephrosis run straight to varying depths in the renal medulla, contributing side
(Fig. 74.13). In children with pelviureteric junction obstruction, a branches to a radially elongated capillary plexus applied to the descend-
crossing vessel is found in 28% of cases (Veyrac et al 2003). Three ing and ascending limbs of renal loops and to collecting ducts. The
anatomical variants of aberrant lower pole crossing vessels have been venous ends of capillaries converge to the ascending vasa recta, which
described: anterior to the dilated pelvis or pelviureteric junction, or drain into arcuate or interlobular veins. An essential feature of the vasa
inferior to the pelviureteric junction, causing kinking of the ureter recta (particularly in the outer medulla) is that both ascending and | 1,718 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
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retPaHC
A
B
Fig. 74.13 Marked dilation of the right renal pelvis (*) and calyces, and
non-dilation of the right ureter (without an associated lesion) due to
ureteropelvic junction obstruction. Note a crossing inferior right renal vein
(arrow) at the level of the obstruction. A, A coronal maximum-intensity
projection of the abdomen. B, An axial contrast-enhanced CT image of
the abdomen. | 1,719 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
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B
Abdominal aorta
Superior mesenteric artery Renal artery
Right renal artery Aorta Left renal artery
Superior renal
polar artery
13% 10%
Superior renal Inferior renal
polar artery polar artery
A
7% 5%
1
2
Fig. 74.11 A, An axial multislice CT renal angiogram. B, Variations in the
number and patterns of branching of the renal artery (percentages are
approximate). C, An intraoperative angiogram of the left kidney,
demonstrating the main renal artery (1), segmental renal arteries (2) and their
subsequent branches. (B, With permission from Waschke J, Paulsen F (eds),
C Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban and Fischer.
Copyright 2013.)
descending vessels are grouped into vascular bundles, within which the Arcuate veins drain into interlobar veins, which anastomose and form
external aspects of both types are closely apposed, bringing them close the renal vein.
to the limbs of renal loops and collecting ducts. As these bundles con- The large renal veins lie anterior to the renal arteries and open into
verge centrally into the renal medulla, they contain fewer vessels; some the inferior vena cava almost at right angles (see Fig. 59.7; Fig. 74.17).
terminate at successive levels in neighbouring capillary plexuses. This The left is three times longer than the right (7.5 cm and 2.5 cm, respec-
proximity of descending and ascending vessels to each other and to tively), and for this reason, the left kidney is the preferred side for live
adjacent ducts provides the structural basis for the countercurrent donor nephrectomy. The left renal vein runs from its origin in the renal
exchange and multiplier phenomena (Fig. 74.16). These complex renal hilum, posterior to the splenic vein and the body of pancreas, and then
vascular patterns show regional specializations that are closely adapted across the anterior aspect of the aorta, just below the origin of the
to the spatial organization and functions of renal corpuscles, tubules superior mesenteric artery. Nutcracker syndrome, characterized by left
and ducts (see below). renal vein hypertension secondary to compression of the vein between
the aorta and the superior mesenteric artery, has been associated with
haematuria and varicocele in children. The left gonadal vein enters the
Renal veins
left renal vein from below, and the left suprarenal vein, usually receiving
one of the left inferior phrenic veins, enters it above but nearer the
Fine radicles from the venous ends of the peritubular plexuses converge midline. The left renal vein enters the inferior vena cava a little superior
to join interlobular veins, one with each interlobular artery. Many inter- to the right. The right renal vein is behind the descending duodenum
lobular veins begin beneath the fibrous renal capsule by the conver- and, sometimes, the lateral part of the head of the pancreas. It can be
gence of several stellate veins, which drain the most superficial zone of extremely short (less than 1 cm), such that safe nephrectomy may
the renal cortex and so are named from their surface appearance. Inter- require excision of a cuff of the inferior vena cava.
lobular veins pass to the corticomedullary junction and also receive The left renal vein may be double, one vein passing posterior, and
some ascending vasa recta before ending in arcuate veins (which accom- the other anterior, to the aorta before joining the inferior vena cava.
pany arcuate arteries), and anastomose with neighbouring veins. This is sometimes referred to as persistence of the ‘renal collar’. The | 1,720 | 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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retPaHC
Fig. 74.12 A resin corrosion cast of human
kidneys. Ureters, pelves and calyces are yellow;
aorta, renal arteries and their branches are red.
(Prepared by the late DH Tompsett of the Royal
College of Surgeons of England. With permission
from the Museums of The Royal College of
Surgeons.)
Juxtamedullary renal corpuscle
Cortical renal corpuscle
Renal
lobe Renal lobule Arcuate artery and vein
Interlobular artery
Capsular network
Medullary rays
Capsule
Outer
cortex
Cortex
Juxtamedullary
cortex
Outer
medulla
Renal
Vasa recta
column
Pyramid Interlobar artery and vein
Inner
medulla
Papilla
Minor calyx
Area cribrosa
Major calyx
Fig. 74.14 The major structures in the kidney cortex and medulla (left), the position of cortical and juxtamedullary nephrons (middle), and the major
blood vessels (right). | 1,721 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
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Apical Apical
Apical
Superior
Superior
Superior
Posterior
Posterior
Middle Middle
Middle
Inferior Inferior
Inferior
Anterior Lateral Posterior
Fig. 74.15 The segmental arterial anatomy of the right kidney. The posterior division branches near the hilum before the anterior division divides into the
other segmental arteries.
anterior vein may be absent so that there is a single retro-aortic left renal Renal corpuscle
vein. The left renal vein may have to be ligated during surgery for aortic
Renal corpuscles are small, rounded structures averaging 0.2 mm
aneurysm because it has such a close relationship with the aorta; this
in diameter, visible in the renal cortex deep to a narrow peripheral corti-
seldom results in any harm to the kidney, provided that the ligature is
cal zone (Fig. 74.18; see Fig. 74.16). Each has a central glomerulus of
placed medial to the draining gonadal and suprarenal veins, since these
vessels and a glomerular (Bowman’s) capsule, from which the renal
usually provide adequate collateral venous drainage. The right renal
tubule originates.
vein has no significant collateral drainage and cannot be ligated with
There are about 1 million renal corpuscles in each kidney, their
impunity.
number (which may be determined, in part, by intrauterine factors)
decreasing with age; this process is accelerated by raised blood pressure.
Lymphatic drainage
After birth, new nephrons cannot be developed; a lost nephron can
never be replaced. The decrease in corpuscular numbers with age is
Renal lymphatic vessels begin in three plexuses: around the renal reflected in a corresponding reduction in the rate of glomerular filtra-
tubules, under the renal capsule, and in the perirenal fat (the latter two tion from the fourth decade onwards.
connect freely). Collecting vessels from the intrarenal plexus form four
or five trunks that follow the renal vein to end in the lateral aortic nodes; Glomerulus
the subcapsular collecting vessels join them as they leave the hilum. A glomerulus is a collection of convoluted capillary blood vessels,
The perirenal plexus drains directly into the same nodes. united by a delicate mesangial matrix and supplied by an afferent arte-
riole which enters the capsule opposite the urinary pole, where the
filtrate enters the tubule (Davies et al 2001). (The term glomerulus is
INNERVATION
used most frequently to describe the entire renal corpuscle.) An efferent
arteriole emerges from the same point, the vascular pole of the corpus-
Rami from the coeliac ganglion and plexus, aorticorenal ganglion, cle. Glomeruli are simple in form until late prenatal life; some remain
lowest thoracic splanchnic nerve, first lumbar splanchnic nerve and so for about 6 months after birth, the majority maturing by 6 years and
aortic plexus form a dense plexus of autonomic nerves around the renal all by 12 years. Low birth weight, defined as a weight less than 2500 g
artery (see Figs 59.4, 59.5). at birth, is associated with a reduction in the number and volume of
Small ganglia occur in the renal plexus, the largest usually behind glomeruli (Manalich et al 2000).
the origin of the renal artery. The plexus continues into the kidney
around the arterial branches and supplies the vessels, renal glomeruli Bowman’s capsule
and, especially, the cortical tubules. Axons from plexuses around the Bowman’s capsule is the blind expanded end of a renal tubule, and is
arcuate arteries innervate juxtamedullary efferent arterioles and vasa deeply invaginated by the glomerulus. It is lined by a simple squamous
recta, which control the blood flow between the cortex and medulla epithelium on its outer (parietal) wall; its glomerular, juxtacapillary
without affecting the glomerular circulation. Axons from the renal (visceral) wall is composed of specialized epithelial podocytes. Between
plexus contribute to the ureteric and gonadal plexuses. the two walls of the capsule is a flattened urinary (Bowman’s) space,
continuous with the proximal convoluted tubule (Fig. 74.18B; see Fig.
74.16).
MICROSTRUCTURE
Podocytes are stellate cells. Their major (primary) foot processes
curve around the capillary loops and branch to form secondary pro-
The kidney is composed of many tortuous, closely packed uriniferous cesses that are applied closely to the basal lamina; secondary or tertiary
tubules, bounded by a delicate connective tissue in which run blood processes give rise to terminal pedicels (Fig. 74.19A). Pedicels of one
vessels, lymphatics and nerves. Each tubule consists of two embryologi- cell alternate with those of an adjacent cell and interdigitate tightly with
cally distinct parts, the nephron, which produces urine, and the collect- each other, separated by narrow (25 nm) gaps: the filtration slits (Fig.
ing duct, which completes the concentration of urine and through 74.19B). The latter are covered by a dense, membranous, slit diaphragm,
which urine passes out into the calyces of the kidney, the renal pelvis, through which filtrate must pass to enter the urinary space. The dif-
the ureter and urinary bladder. ferentiation of the adult podocyte phenotype is associated with the
presence of several specific proteins, including nephrin, podocin, syn-
Nephron
aptopodin and GLEPP-1. Mutations in these proteins can cause impor-
tant functional problems, e.g. the classic Finnish form of congenital
The nephron consists of a renal corpuscle, concerned with filtration nephritic syndrome is caused by a mutation of NHPS1, coding for
from the plasma, and a renal tubule, concerned with selective resorp- nephrin. The luminal membrane and the slit diaphragm are covered by
tion from the filtrate to form the urine (see Fig. 74.14). Collecting ducts a dense surface coat rich in sialoglycoproteins, which gives this surface
carry fluid from several renal tubules to a terminal papillary duct, a very high negative charge and is one of the key characteristics of the
opening into a minor calyx at the apex of a renal papilla. Papillary perm-selectivity barrier. Differentiated podocytes cannot replicate.
surfaces show numerous minute orifices of these ducts and pressure on The glomerular endothelium is finely fenestrated. The principal
a fresh kidney expresses urine from them. barrier to the passage of fluid from capillary lumen to urinary space is | 1,722 | 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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retPaHC
RENAL CORPUSCLE
Parietal wall of glomerular capsule
Afferent arteriole
Afferent arteriole Granular juxtaglomerular cells
Smooth muscle cell
Macula densa
Extraglomerular
mesangial cells ‘Polar cushion’
(lacis cells)
Distal convoluted tubule Granular juxtaglomerular cells
(renin-secreting)
Juxtaglomerular
apparutus Efferent arteriole Urinary space
Basal lamina Fenestrated endothelial cell
Podocyte nucleus
Mesangial cell
Efferent arteriole
Filtration slits
Glomerular capsule (parietal layer)
Urinary (Bowman's) space
Podocyte of visceral layer of glomerular capsule Glomerular capillaries
Selective resorption
and secretion
Ultrafiltration
Na+
Cl–
Distal convoluted tubule
Water
Glucose Selective
Amino acids resorption
Proteins
Ascorbic acid
HCO–
3
Proximal convoluted tubule
A Collecting duct
Countercurrent
exchange and
multiplication
Loop of Henle and vasa recta
ADH controlled
water resorption
B
Thick segment
Increased Thin segment
osmolality
Vasa recta
Fig. 74.16 The regional microstructure and principal activities of a kidney nephron and collecting duct. For clarity, a nephron of the long loop
(juxtamedullary) type is shown. Abbreviations: ADH, antidiuretic hormone. | 1,723 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
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BV
I A
G
G
A
A
Inferior vena cava Left renal vein
G
B
Fig. 74.18 A, A low-power histological section of the renal cortex,
containing glomeruli (G), proximal and distal convoluted tubules and
blood vessels (BV). B, A higher-power view of the section demonstrating
several glomeruli (G) within a network of mesangium. The glomerular
basement membrane of the capillaries is continuous with Bowman’s
capsule (short arrow) of the glomerulus, and is separated from it by
Bowman’s space (long arrow).
thickness of the glomerular basement membrane increases throughout
B
childhood; the rate of increase decreases after the age of 11 years
(Ramage et al 2002).
Right kidney Right renal vein Left kidney
Left testicular vein Irregular mesangial cells, with phagocytic and contractile properties,
lie within and secrete the glomerular mesangium, a specialized connec-
Fig. 74.17 A, A coronal maximum-intensity projection contrast-enhanced
magnetic resonance angiogram image obtained during the arterial phase tive tissue that binds the loop of glomerular capillaries and fills the
of enhancement. It demonstrates normal-appearing single renal arteries spaces between endothelial surfaces that are not invested by podocytes
(short arrows), normal-appearing single renal veins (long arrows), a (see Figs 74.18B, 74.16). Mesangial cells are related to vascular pericytes
normal-appearing abdominal aorta (A), and a normal-appearing suprarenal and are concerned with the turnover of glomerular basement membrane.
inferior vena cava (I). The infrarenal inferior vena cava has not yet been They clear the glomerular filter of immune complexes and cellular
enhanced. B, A CT renal venogram, acquired from a multislice CT debris, and their contractile properties help to regulate blood flow.
examination and reconstructed as a three-dimensional, surface-shaded Similar cells, the extraglomerular mesangial (lacis) cells, lie outside the
reformat. glomerulus at the vascular pole and form part of the juxtaglomerular
apparatus.
Renal tubule
the glomerular basal lamina, the fused endothelial and podocyte basal
laminae (see Fig. 74.19B). This is usually 0.33 µm thick in humans, and A renal, or uriniferous, tubule consists of a glomerular capsule that
acts as a selective filter, allowing the passage from blood, under pres- leads into a proximal convoluted tubule, connected to the capsule by
sure, of water and various small molecules and ions in the circulation. a short neck and continuing into a sinuous or coiled convoluted part
Haemoglobin may cross the filter, but larger molecules and those of (see Fig. 74.16). This straightens as it approaches the medulla, and
similar size with a negative charge are largely retained. Most protein becomes the descending thick limb of the loop of Henle, and then the
that does enter the filtrate is selectively resorbed and degraded by cells ascending limb by an abrupt U-turn. The limbs of the loop of Henle
of the proximal convoluted tubule. are narrower and thin-walled within the deeper medullary tissue, where
The glomerular basement membrane serves as the skeleton of the they become the descending and ascending thin segments. The ascend-
glomerular tuft. Its outer aspect is completely covered by podocytes, ing thick limb continues into the distal tubule. The tubule wall shows
and the interior is filled by capillaries and a delicate mesangial matrix a focal thickening, the macula densa, where it comes close to the vas-
(mesangium). The major components of the glomerular basement cular pole of its parent glomerulus at the start of the convoluted part
membrane are laminin and type IV collagen (both of which are of the distal tubule. The nephron finally straightens once more as the
expressed as unique isoforms), and heparin sulphate proteoglycans. The connecting tubule, which ends by joining a collecting duct. | 1,724 | 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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CC
V
P
CC P
P V
CC
A
Fig. 74.20 A histological cross-section of a part of the renal medulla.
Note the large collecting ducts and small, thin segments of the loop of
P
Henle, interspersed with vasa recta (V) (trichrome-stained).
E numerous other enzymes concerned with ion transport. Water and
F P 1 other solutes pass between cells (paracellular transport) passively, along
osmotic and electrochemical gradients, probably through leaky apical
FS tight junctions. Pinocytotic vesicles are found near the apical surface,
BL FS P 1 and represent the means by which small proteins and peptides from
P 2 P BL the filtrate are internalized and degraded by associated lysosomes. Per-
P 2 1 E oxisomes and lipid droplets abound in the cytoplasm.
BL
The loop of Henle consists of a thin segment (30 µm in diameter),
E C
lined by low cuboidal to squamous cells, and a thick segment (60 µm
P 2 F F in diameter), composed of cuboidal cells like those in the distal con-
B C voluted tubule. The thin segment forms most of the loop in juxtamedul-
lary nephrons, which reach deep into the medulla. Few organelles
P
1 appear in cells lining the thin segment, indicating that these cells play
Fig. 74.19 A, A scanning electron micrograph showing podocytes forming a passive, rather than an active, role in ion transport. The thick segment
the visceral layer of Bowman’s capsule in the renal corpuscle. Their cell is composed of cuboidal epithelium with many mitochondria, deep
bodies (P) send out primary processes that branch several times and end basolateral folds and short apical microvilli, indicating a more active
in fine pedicels, which wrap tightly around the glomerular capillaries (C), metabolic role. The thick limb of the loop of Henle is the source of
and interdigitate with similar pedicels from a neighbouring podocyte.
Tamm–Horsfall protein in normal urine.
B, An electron micrograph demonstrating the glomerular filtration
Cells of the distal tubule are cuboidal and resemble those in the
apparatus. Note the endothelial cells of fenestrated capillaries, the
proximal tubule. They have few microvilli, and so the tubular lumen
filtration slits between podocyte pedicels and their thick shared basal
has a more distinct outline. The basolateral folds containing mitochon-
lamina. Abbreviations: BL, basal lamina; C, lumina of capillary loops;
dria are deep, almost reaching the luminal aspect. Enzymes concerned
E, endothelial cell cytoplasm; F, fenestrations; FS, filtration slits; P,
with active transport of sodium, potassium and other ions are abun-
podocyte; P and P, primary and secondary foot processes that rest on
the glomerul1 ar basa2 l laminae. (A, With permission from Igaku-Shoin, dant. At the junction of the straight and convoluted regions, the distal
Tokyo, from Fujita T, Tanaka K, Tokunaga J 1981 SEM Atlas of Cells and tubule comes close to the vascular pole of its parent renal corpuscle.
Tissues. B, With permission from Young B, Heath JW 2000 Wheater’s Here, tubular cells form the macula densa, a sensory structure that is
Functional Histology. Edinburgh: Churchill Livingstone.) concerned with the regulation of blood flow and, thus, filtration rate.
Cells in the terminal part of the distal tubule have fewer basal folds and
mitochondria, and constitute a connecting duct formed from metane-
Collecting ducts originate in the cortical medullary rays and join phric mesenchyme during embryogenesis. Collecting ducts are lined by
others at intervals. They finally open into wider papillary ducts, which simple cuboidal or columnar epithelium. This increases in height from
open on to a papilla, their numerous orifices forming a perforated area the cortex, where the ducts receive the contents of distal tubules, to the
cribrosa on the surface at its tip (see Fig. 74.14). wide papillary ducts that discharge at the area cribrosa. The pale-
Renal tubules are lined throughout by a single-layered epithelium staining principal cells have relatively few organelles or lateral interdigi-
(see Fig. 74.16; Fig. 74.20). The type of epithelial cell varies according tations, and only occasional microvilli. A second cell type, intercalated
to the functional roles of the different regions, e.g. active transport and or dark cells (also present in smaller numbers in the distal convoluted
passive diffusion of various ions and water into and out of the tubules; tubule), has longer microvilli and more mitochondria, and secretes H+
reabsorption of organic components such as glucose and amino acids; into the filtrate; these cells function in the maintenance of acid–base
uptake of any proteins which leak through the glomerular filter. homeostasis.
The proximal convoluted tubule is lined by cuboidal or low colum-
Renal vessels
nar epithelium and has a brush border of tall microvilli on its luminal
surface. The shape of the cells depends on tubular fluid pressure, which,
in life, distends the lumen and flattens the cells (they become taller Renal, interlobar and arcuate arteries are typical large muscular arteries
when glomerular blood pressure falls post mortem or at biopsy). The and the interlobular vessels resemble small muscular arteries. Afferent
cytoplasm of proximal tubular cells is strongly eosinophilic and the glomerular vessels have a typical arteriolar structure with a muscular
nuclei are euchromatic and central. The basal cytoplasm is rich in coat 2–3 cells thick; this coat and the connective tissue components of
mitochondria, orientated perpendicularly, and the basal plasma mem- the wall diminish near a glomerulus until a point 30–50 µm proximal
brane is highly infolded. The lateral surfaces of adjacent epithelial cells to it, where arteriolar cells begin to show modifications typical of the
interdigitate, increasing the complexity of the basolateral plasma mem- juxtaglomerular apparatus. The efferent arterioles from most cortical
brane. The microvilli on the luminal surfaces significantly increase the glomeruli have thicker walls and a narrower calibre than corresponding
area of plasma membrane in contact with tubular fluid and the extra- afferents. Although the afferent arteriole is generally considered to be
tubular space, facilitating the transport of ions and small molecules solely responsible for tubuloglomerular feedback, the peritubular and
against steep concentration gradients. The abundant mitochondria medullary capillaries possess a well-defined basal lamina and their
supply the energy, as adenosine triphosphate (ATP), needed for this endothelial cells have typically fenestrated cytoplasm, as do the ascend-
process. Sodium/potassium adenosine triphosphatase (Na+/K+ ATPase) ing vasa recta, whereas the descending vasa recta have a thicker, continu-
is located in apical and basal membranes, and the cytoplasm contains ous endothelium (Davies 1991). | 1,725 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
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Other renal cells The rest of the tubule reabsorbs most of the water (to a variable extent,
up to 95%), so that, when it reaches the calyces, urine is generally much
reduced in volume and hypertonic to blood. The process depends on
Other cells essential to renal structure and function lie between the
the establishment of high osmolality in the medullary interstitium, in
renal tubules and blood vessels. Connective tissue is inconspicuous in
order to exert sufficient osmotic pressure on water-permeable regions
the cortex but prominent in the medulla, particularly in the papillae.
of the tubule, and is achieved by a countercurrent multiplier
Medullary interstitial cells, which may be modified fibroblasts, form
mechanism.
vertical stacks of tangentially orientated cells between the more distal
collecting ducts, like the rungs of a ladder. These cells secrete prosta-
Countercurrent multiplier mechanism
glandins and may contribute, with cortical tubular cells, to the renal
The countercurrent multiplier mechanism is responsible for producing
source of erythropoietin.
a high osmolality in the extratubular interstitial tissue of the renal
medulla. Water passes freely from the tubular lumen into the adjacent
Calyces and pelvis
medullary interstitium along the descending limb of the loop of Henle.
This part of the tubule is less permeable to solutes. In the thick segment
The wall of the proximal part of the urinary tract is composed of three of the ascending limb, sodium and chloride ions are actively transported
layers: an outer connective tissue adventitia, an intermediate layer of from the tubule lumen to interstitial spaces, while the tubular epithe-
smooth muscle and an inner mucosa. The mucosal lining of the renal lium remains impermeable to water. The increased interstitial osmolal-
calyces and pelvis is identical in structure to that of the ureter (see ity causes water to be withdrawn from the descending part of the loop,
below). The adventitia consists of loose fibroelastic connective tissue thus concentrating the filtrate. Tubular fluid flows in a countercurrent
that merges with retroperitoneal areolar tissue. Proximally, the coat on its descent into and ascent out of the medulla; it is augmented by
fuses with the fibrous capsule of the kidney lining the renal sinus. new isotonic fluid entering the loop, and depleted by hypotonic fluid
The smooth muscle of the renal calyces and pelvis is composed of leaving the loop as solutes are actively resorbed. The osmotic gradient
two distinct types of smooth muscle cell. One type of muscle cell is within the interstitium is, thus, multiplied from the corticomedullary
identical to that described for the ureter and can be traced proximally boundary to the medullary pyramids, where it reaches an equilibrium
through the pelviureteric region and renal pelvis, as far as the minor of four to five times the osmolality of plasma. Although the tonicity of
calyces. The other type of cell forms the muscle coat of each minor calyx the tubular fluid changes during its passage through the steep osmotic
and continues into the major calyces and pelvis, where it forms a distinct gradient within the medulla, the osmotic gradient between ascending
inner layer. The cells also form a thin sheet of muscle that covers each and descending limbs at each level never exceeds 200 mOsm/kg, a force
minor calyx and extends across the renal parenchyma between the that can be sustained by the cells of the tubular wall.
attachments of neighbouring minor calyces, thereby linking each minor
calyx to its neighbours. This discrete inner layer of atypical smooth Countercurrent exchange mechanism
muscle ceases in the pelviureteric region, so that the proximal ureter Rapid removal of ions from the renal medulla by the circulation of
lacks such an inner layer. Pacemaker cells that initiate renal pelvic and blood is minimized by another looped countercurrent system. This is
ureteric peristalsis are sited within the calyces (Gosling and Dixon 1974). the countercurrent exchange mechanism, in which arterioles entering
These allow coordinated peristalsis of the ureter six times a minute. the medulla pass for long distances parallel to the venules leaving it,
before ending in capillary beds around tubules. This close apposition
of oppositely flowing blood allows the direct diffusion of ions from
PRODUCTION OF URINE outflowing to inflowing blood, so that the vasa recta (see Fig. 74.14)
conserve the high osmotic pressure in the medulla.
Glomerular filtration
Concentration of urine
Glomerular filtration (see Figs 74.14, 74.16) is the passage of water
containing dissolved small molecules from the blood plasma to the Because sodium and chloride ions are selectively resorbed by the cells
urinary space in the glomerular capsule. Larger molecules, e.g. plasma of the ascending limbs and distal tubules under aldosterone control,
proteins above 70 kilodaltons and those with a net negative charge, the filtrate at the distal end of the convoluted tubules is hypotonic. As
polysaccharides, lipids and cells, are largely retained in blood by the it reaches the collecting ducts, fluid descends again through the medulla
selective permeability of the glomerular basal lamina. and, thus, re-enters a region of high osmotic pressure. The cells lining
Filtration occurs along a steep pressure gradient between the large the collecting ducts are variably permeable to water, under the influence
glomerular capillaries and the urinary space, the principal structure of neurohypophysial ADH. Water follows an osmotic gradient into the
separating the two being the glomerular basal lamina (Fig. 74.19B). adjacent extratubular spaces, so that the tonicity of the filtrate gradually
This gradient far exceeds the colloid osmotic pressure of blood, which rises along collecting ducts, until, at the tip of the renal pyramids, it is
opposes the outward flow of filtrate. In the peripheral renal cortex, the above that of blood. This complex system is highly flexible and the
arteriolar pressure gradient is enhanced because afferent glomerular balance between the rate of filtration and absorption can be varied to
arterioles are wider than efferent glomerular arterioles. In all glomeruli, meet current physiological demands.
the rate of filtration can be altered by changes in the tone of the Control of hydrogen and ammonium ion concentrations is essential
glomerular arterioles. When first formed, the glomerular filtrate is iso- to the regulation of acids and bases in the blood. Secretion of various
tonic with glomerular blood and has an identical concentration of ions ions occurs at several sites. Over 91% of ingested potassium is excreted
and small molecules. in urine, largely through secretion by cells of the distal tubule and col-
The assessment of glomerular filtration is fundamental to the diag- lecting duct. (For further details of renal physiology, see Madias and
nosis of renal glomerular pathology and the management of drug Adrogué (2005), Tannen and Hallows (2005), Singh and Thomson
therapy, where clearance depends on the glomerular filtration, and in (2011).)
chronic kidney disease to facilitate timely management decisions. Meas-
urements of glomerular filtration rate (GFR) are based on the renal Juxtaglomerular apparatus
clearance of a marker in plasma, expressed as the volume of plasma
completely cleared of the marker per unit time. Markers used to measure
The juxtaglomerular apparatus provides a tubuloglomerular feedback
GFR may be endogenous (creatinine, urea) or exogenous (inulin, iotha-
system that maintains systemic arterial blood pressure during a reduc-
lamate) substances. The ideal marker is endogenous, freely filtered by
tion in vascular volume and decrease in filtration rate. The elements of
the glomerulus, neither reabsorbed nor secreted by the renal tubule,
a juxtaglomerular apparatus are juxtaglomerular and lacis cells, and the
and eliminated only by the kidney.
macula densa. The afferent and efferent arterioles at the vascular pole
of a glomerulus and the macula densa of the distal tubule of the same
Selective resorption
nephron lie in close proximity, enclosing a small cone of tissue popu-
lated by extraglomerular mesangial (lacis) cells (see Fig. 74.16). The
Selective resorption from the filtrate is an active process and occurs cells of the tunica media of afferent and, to a lesser extent, efferent,
mainly in the proximal convoluted tubules, which resorb glucose, arterioles differ from typical smooth muscle cells. These juxtaglomeru-
amino acids, phosphate, chloride, sodium, calcium and bicarbonate, lar cells are large, rounded, myoepithelioid cells and their cytoplasm
and take up small proteins (e.g. albumin) by endocytosis. Cells of the contains many mitochondria and dense, renin-containing vesicles,
proximal tubules are permeable to water, which passes out of the 10–40 nm in diameter. Each macula densa of the distal tubule is a
tubules passively, so that the filtrate remains locally isotonic with blood. cluster of up to 40 tightly packed cells in the tubule wall; the cells have | 1,726 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
ureter
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A B Fig. 74.21 Relations of the lower
ureter, seen from above. A, The
Ureter male pelvis. B, The female pelvis.
Ureter Common iliac artery (With permission from Drake RL,
Vogl AW, Mitchell A (eds), Gray’s
Anatomy for Students, 2nd ed,
Elsevier, Churchill Livingstone.
Copyright 2010.)
Internal iliac artery
Uterine artery
Uterus
Vas deferens
Pelvic brim
(pelvic inlet)
Bladder
Anterior
abdominal wall
large, oval nuclei and apically concentrated mitochondria. They are the gonadal vessels. It enters the lesser pelvis either anterior to the end
osmoreceptors, sensing the NaCl content of the filtrate after its passage of the common iliac vessels or at the origin of the external iliac vessels
through the loop of Henle. (Fig. 74.22).
When NaCl concentrations in the filtrate change, tubuloglomerular The inferior vena cava is medial to the right ureter, while the left
feedback mechanisms operate to maintain the inverse relationship ureter is lateral to the aorta. The inferior mesenteric vein has a long
between salt concentration and glomerular filtration rate. Juxtaglomeru- retroperitoneal course lying close to the medial aspect of the left ureter.
lar cells release renin, an enzyme that acts on circulating angiotensino- At its origin, the right ureter is usually overlapped by the descending
gen to activate the cascade whereby angiotensin II increases blood part of the duodenum. It descends lateral to the inferior vena cava, and
pressure (and therefore filtration rate), stimulates aldosterone and ADH is crossed anteriorly by the right colic and ileocolic vessels. Near the
release and increases sodium ion and water resorption, primarily from superior aperture of the lesser pelvis, it passes behind the lower part of
the distal tubule, to increase plasma volume. Macula densa cells are the mesentery and terminal ileum. The left ureter is crossed by the
thought to respond to high salt concentration in the distal tubule by gonadal and left colic vessels. It passes posterior to loops of jejunum
releasing nitric oxide, which inhibits the tubuloglomerular feedback and sigmoid colon and its mesentery in the posterior wall of the inter-
response and reduces filtration rate. The role of macula densa cells in sigmoid recess.
the stimulation of renin release to increase filtration rate is less well In the pelvis, the ureter lies in extraperitoneal areolar tissue. At first,
understood. it descends posterolaterally on the lateral wall of the lesser pelvis along
The third element of the juxtaglomerular apparatus is a population the anterior border of the greater sciatic notch. Opposite the ischial
of extraglomerular mesangial cells that form a network (or lace; hence, spine, it turns anteromedially into fibrous adipose tissue above levator
their alternative name of lacis cells) of stellate cells connecting the ani to reach the base of the bladder. On the pelvic side wall, it is anterior
macula densa sensory cells with the juxtaglomerular effector cells. It is to the internal iliac artery and the beginning of its anterior trunk, pos-
likely that extraglomerular mesangial cells transmit the sensory signal, terior to which are the internal iliac vein, lumbosacral nerve and sacro-
possibly through gap junctions. They may also signal to contractile iliac joint. Laterally, it lies on the fascia of obturator internus. It
glomerular mesangial cells and effect vasoconstriction directly within progressively crosses to become medial to the umbilical, inferior vesical
the glomerulus. Adrenergic nerve fibres occur in small numbers among and middle rectal arteries.
these cells. In males, the pelvic ureter hooks under the vas deferens (Fig. 74.23);
it then passes anterior and slightly superior to the upper pole of the
seminal vesicle to traverse the bladder wall obliquely before opening at
URETER
the ipsilateral trigonal angle. Its terminal part is surrounded by tributar-
ies of the vesical veins. In females, the pelvic part initially has the same
The ureters are two muscular tubes whose peristaltic contractions convey relations as in males but, anterior to the internal iliac artery, it is imme-
urine from the kidneys to the urinary bladder (see Figs 74.1, 74.10, Fig. diately behind the ovary, forming the posterior boundary of the ovarian
74.21). Each measures 25–30 cm in length, is thick-walled and narrow, fossa (see Fig. 77.8). In the anteromedial part of its course to the
and is continuous superiorly with the funnel-shaped renal pelvis. Each bladder, it is related to the uterine artery, uterine cervix and vaginal
descends slightly medially, anterior to psoas major, and enters the pelvic fornices. It is in extraperitoneal connective tissue in the inferomedial
cavity, where it curves initially laterally, then medially, to open into the part of the broad ligament of the uterus, where it may be damaged
base of the urinary bladder. The diameter of the ureter is normally 3 mm, during hysterectomy (see Fig. 77.7). In the broad ligament, the uterine
but is slightly less at its junction with the renal pelvis, at the brim of the artery is anterosuperior to the ureter for approximately 2.5 cm and then
lesser pelvis near the medial border of psoas major, and where it runs crosses to its medial side to ascend alongside the uterus. The ureter turns
within the wall of the urinary bladder, which is its narrowest part. These forwards slightly above the lateral vaginal fornix and is, generally, 2 cm
are the most common sites for renal stone impaction. lateral to the supravaginal part of the uterine cervix in this location. It
then inclines medially to reach the bladder, with a variable relation to
the anterior aspect of the vagina. As the uterus is commonly deviated
RELATIONS to one side, one ureter, usually the left, may be more extensively
apposed to the vagina, and may cross the midline.
In the abdomen, the ureter descends posterior to the peritoneum on The distal 1–2 cm of each ureter is surrounded by an incomplete
the medial part of psoas major, which separates it from the tips of the collar of non-striated muscle (sheath of Waldeyer). The ureters pierce
lumbar transverse processes. During surgery on intraperitoneal struc- the posterior aspect of the bladder and run obliquely through its wall
tures, the ureter can be tented up as the peritoneum is drawn anteriorly, for a distance of 1.5–2.0 cm before terminating at the ureteric orifices
resulting in inadvertent ureteric injury. Anterior to psoas major, it (see Fig. 75.10B). This arrangement is believed to assist in the preven-
crosses anterior to the genitofemoral nerve and is obliquely crossed by tion of reflux of urine into the ureter, since the intramural ureters are | 1,727 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
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Fig. 74.22 Relations of male
lower right ureter. (With
Middle permission from Walsh PC,
sacral Retik AB, Vaughan ED et al
Common
artery (eds) 2002 Campbell’s Urology,
iliac artery
8th edn. Philadelphia:
Iliolumbar Saunders.)
Deep artery
circumflex iliac
artery Superior
gluteal
Inferior artery
epigastric
artery Lateral
sacral
Right ureter artery
Internal iliac Inferior
artery gluteal
artery
External
iliac artery
Internal
Median umbilical pudendal
ligament artery
Obturator artery
Sciatic nerve
Vas deferens
Middle rectal
Superior vesical
artery
artery
Left ureter Inferior
vesical
artery
Bladder
Prostate gland Rectum
thought to be occluded during increases in bladder pressure at the time or pass directly to the lateral aortic nodes near the origin of the gonadal
of micturition. There is no evidence of a classic ureteral sphincter mech- artery; those from the lower abdominal ureter drain to the common
anism in humans. The longitudinally orientated muscle bundles of the iliac nodes; and those from the pelvic ureter drain to common, external
terminal ureter continue into the bladder wall and, at the ureteric ori- or internal iliac nodes.
fices, become continuous with the superficial trigonal muscle. In the
distended bladder, in both sexes, the ureteric openings are usually 5 cm
INNERVATION
apart, and 2.5 cm apart when the bladder is empty.
The ureter is supplied from the lower three thoracic, first lumbar, and
VASCULAR SUPPLY AND LYMPHATIC DRAINAGE the second to fourth sacral segments of the spinal cord by branches
from the renal and aortic plexuses, and the superior and inferior
Arteries hypogastric plexuses (see Figs 59.3, 75.11). The ureteric nerves consist
of relatively large bundles of axons that form an irregular plexus in the
adventitia of the ureter. The plexus receives branches from the renal and
The ureter is supplied by branches from the renal, gonadal, common
aortic plexuses (in its upper part); from the superior hypogastric plexus
iliac, internal iliac, vesical and uterine arteries, and the abdominal aorta.
and hypogastric nerve (in its intermediate part); and from the hypogas-
The pattern of distribution is subject to much variation. The abdominal
tric nerve and inferior hypogastric plexus (in its lower part). Numerous
ureter is supplied from vessels originating medial to the ureter; the pelvic
small branches penetrate the ureteric muscle coat; some of the adven-
ureter is supplied by vessels lateral to the ureter (Fig. 74.24). There is a
titial nerves accompany the blood vessels and branch with them as they good longitudinal anastomosis between these branches on the wall of
extend into the muscle layer; others are unrelated to the vascular supply
the ureter, which means that the ureter can be safely transected at any
and lie free in the adventitial connective tissue around the circumfer-
level intraoperatively, and a uretero-ureterostomy performed, without
ence of the ureter.
compromising its viability. The branches from the inferior vesical artery
The density of innervation increases gradually from the renal pelvis
are constant in their occurrence and supply the lower part of the ureter,
and upper ureter (where autonomic nerves are sparse) to a maximum
as well as a large part of the trigone of the bladder. The branch from the
density in the juxtavesical segment. At least three different neurotrans-
renal artery is also constant and is preserved whenever possible in renal
mitter phenotypes – cholinergic, noradrenergic and peptidergic (sub-
transplantation to ensure good vascularity of the ureter.
stance P) – are well known and others have been reported. The
functional significance of these different types of autonomic nerve fibres
Veins
in relation to ureteric smooth muscle activity is not fully understood;
although they are thought to influence the inherent motility of the
The venous drainage of the ureters generally follows the arterial supply. ureter, they are not essential for the initiation and propagation of ure-
teric contraction waves. A branching plexus of fine cholinergic,
Lymphatic drainage
noradrenergic and peptidergic axons occurs throughout the lamina
propria and extends from the inner aspect of the muscle coat towards
Lymph vessels draining the ureter begin in submucosal, intramuscular the base of the urothelium. Some of these axons form perivascular
and adventitial plexuses, which all communicate. Collecting vessels plexuses, while others lie in isolation from the vascular supply and may
from the upper abdominal ureter may join the renal collecting vessels be sensory in function. | 1,728 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
ureter
1253
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retPaHC
Median
Apex of bladder umbilical ligament
Body of bladder,
muscular layer
Ureter
Vas
deferens
Ampulla of
vas deferens
Ampulla of
vas deferens,
diverticula
Seminal vesicle
of ampulla
Seminal vesicle
Prostate,
posterior surface
Fig. 74.25 A coronal CT urogram volume-rendered image demonstrates a
Fig. 74.23 The posterior aspect of the male urogenital organs, showing duplicated right collecting system and ureter, along with dilation of the
the relationship of the lower ureter to the vas deferens and seminal collecting system of the lower pole moiety. No urothelial lesion is seen.
vesicles. (With permission from Waschke J, Paulsen F (eds), Sobotta Atlas
of Human Anatomy, 15th ed, Elsevier, Urban and Fischer. Copyright 2013)
initiated, the contraction is propagated through the wall of the adjacent
major calyx and activates the smooth muscle of the renal pelvis. Con-
Fig. 74.24 The arterial
supply of the left traction waves are propagated away from the kidney, and so undesirable
ureter. The proximal pressure rises are not directed against the renal parenchyma. Since
part takes its blood several potential pacemaker sites exist, the initiation of contraction
supply medially, and waves is unimpaired by partial nephrectomy; the minor calyces
the distal part is spared by the resection remain in situ to continue their pacemaking
supplied laterally. (With function. Pressures within the ureter at the time of peristalsis reach
permission from Walsh 20–80 cm HO.
2
PC, Retik AB, Vaughan Experimental evidence indicates that autonomic nerves do not play
ED et al (eds) 2002 a major part in the propagation of peristalsis. It seems more likely
Campbell’s Urology, that they play a modulatory role on the contractile events occurring in
8th edn. Philadelphia: the musculature of the upper urinary tract. The most likely mecha-
Saunders.) nism to account for impulse propagation is myogenic conduction
Renal artery mediated by the electrotonic coupling of one muscle cell to its imme-
diate neighbours by means of intercellular ‘gap’ junctions; there are
Gonadal artery numerous regions of close approach between ureteric smooth muscle
cells and also between both types of muscle cell in the renal pelvis
Aorta
and calyces.
Referred pain Excessive distension of the ureter or spasm of its
muscle may be caused by a stone (calculus) and provokes severe pain
Common iliac artery (ureteric colic, which is commonly, but mistakenly, called renal colic).
The pain is spasmodic and agonizing, particularly if the obstruction is
gradually forced down the ureter by the muscle spasm. It is referred to
cutaneous areas innervated from spinal segments that supply the ureter,
mainly T11–L2, and shoots down and forwards from the loin to the
Internal iliac artery
groin and scrotum or labium majus; it may extend into the proximal
anterior aspect of the thigh by projection to the genitofemoral nerve
Superior vesical artery (L1, 2). The cremaster, which has the same innervation, may reflexly
retract the testis.
Uterine artery
Middle rectal artery
RENAL AND URETERIC CALCULI
Vaginal artery
Inferior vesical artery An understanding of intrarenal and ureteric anatomy is essential
when managing patients with calculi, particularly now that mini-
mally invasive techniques are widely used to treat this common
pathology.
Ureteric peristalsis
MICROSTRUCTURE
Under normal conditions, contraction waves originate in the proximal
part of the upper urinary tract and are propagated in an anterograde Like the calyces and the renal pelvis, the wall of the ureter is composed
direction towards the bladder. Atypical smooth muscle cells in the wall of an external adventitia, a smooth muscle layer and an inner mucosal
of the minor calyces act individually or collectively as pacemaker sites. layer. The mucosal layer consists of a urothelium (see Fig. 2.5D) and
A peristaltic wave begins at one (or possibly more) of these sites. Once an underlying connective tissue lamina propria. | 1,729 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
1253.e1
47
retPaHC
Smaller renal calculi are treated with extracorporeal shock wave
lithotripsy. Stones in the lower pole of the kidney clear less well if the
angle between the infundibulum of the calyx containing the stone and
the ureter is acute, or if there is a particularly long and narrow infundibu-
lum. Percutaneous stone extraction is most frequently achieved by
puncturing a posterior calyx with a needle.
Ureteric calculi tend to be arrested in their descent in either the
pelviureteric region, or the point where the ureter passes over the pelvic
brim as it crosses the common iliac artery, or the vesico-ureteric junc-
tion, because these are the three areas where the ureter is narrowest.
The vesico-ureteric junction is the narrowest of these areas and can be
responsible for arresting the passage of stones of as little as 2–3 mm.
The kidney and upper ureter move with respiration within the peri-
renal fascia, and this can affect the visualization and tracking of a stone,
both at the time of extracorporeal shock wave lithotripsy and at retro-
grade endoscopy. | 1,730 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
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The ureteric adventitial blood vessels and connective tissue fibres are normal in some individuals. In the male, the ureter can insert at the
orientated parallel to the long axis of the ureter. Throughout its length, bladder neck or posterior urethra, or, rarely, into the seminal vesicle,
the muscle coat of the ureter is fairly uniform in thickness and, in cross- but it always inserts cranial to the external urethral sphincter. In the
section, measures 750–800 µm in width. The muscle bundles that con- female, ectopic insertion can be distal to the external urethral sphincter
stitute this coat are frequently separated from one another by relatively in the urethra, or into the vagina, resulting in persistent childhood
large amounts of connective tissue. However, branches that intercon- incontinence.
nect muscle bundles are common and there is frequent interchange of
muscle fibres between adjacent bundles. As a consequence of this exten- Ureteroceles A ureterocele is a cystic dilation of the lower end of the
sive branching, individual muscle bundles do not spiral around the ureter; the ureteric orifice is covered by a membrane that expands as it
ureter, but form a complex meshwork of interweaving bundles. More- is filled with urine and then deflates as it empties. Ureteroceles can vary
over, unlike the gut (Ch. 65), the muscle bundles are so arranged that in size and usually have no influence on ureteric drainage; however,
morphologically distinct longitudinal and circular layers cannot be they can be a cause of obstruction in the ureter and pelvicalyceal system
clearly distinguished. In the upper part of the ureter, the inner muscle more proximally. Prolapsing ureteroceles, though small, prolapse from
bundles tend to lie longitudinally while those on the outer aspect have their position around the ureterovesical junction region into the urethra,
a circular or oblique orientation. In the middle and lower parts, there causing intermittent bladder outflow obstruction.
are additional outer longitudinally orientated fibres, and as the uretero- They are identified antenatally with ultrasound (Fig. 74.26). In
vesical junction is approached, the muscle coat consists predominantly adults, ureteroceles tend to be bilateral and small, and are often found
of longitudinally orientated muscle bundles. incidentally when the urinary tract is being imaged in the investigation
The mucosa of the ureter consists of an epithelium, the urothelium, of a coincidental pathology. Radiologically, they classically result in a
lying on a layer of subepithelial fibroelastic connective tissue lamina ‘cobra-head’ halo around the ureteric orifice following administration
propria. The latter varies in thickness from 350 to 700 µm and is a of contrast on intravenous urography.
conduit for small blood vessels and bundles of unmyelinated nerve
fibres. Occasional lymphocytes may be present in the lamina propria Retrocaval ureter A persistence of the posterior cardinal vein, asso-
but their aggregation into definitive lymph nodules is rare. The urothe- ciated with high confluence of the right and left common iliac veins or
lium is usually extensively folded, giving the ureteric lumen a stellate a double inferior vena cava, may result in a retrocaval (or circumcaval)
outline. ureter that passes behind the inferior vena cava, usually at the level of
the inferior edge of the third part of the duodenum, before it emerges
Developmental anomalies of the ureter anterior to it to pass from medial to lateral. Retrocaval ureter occurs in
1 in 1500 individuals. Most commonly, it has no clinical sequelae,
Duplex ureters In 1 in 125 individuals, two ureters drain the renal although it can result in upper ureteric obstruction (Fig. 74.27).
pelvis on one side; this is termed a duplex system (Fig. 74.25). Bilateral
duplex ureters occur in approximately 1 in 800 cases. Duplex ureters
are the product of two ureteric buds arising from the mesonephric duct;
they share a single fascial sheath and may either fuse at any point along Bonus e-book images
their course, or remain separate until they insert through separate ure-
teric orifices into the bladder.
Care must be taken not to compromise the blood supply of the
Fig. 74.13 Marked dilation of the right renal pelvis and calyces, and
second ureter when excising or reimplanting a single ureter of a duplex.
non-dilation of the right ureter without an associated lesion due to
The ureter from the upper pole of the kidney (the longer ureter) inserts
ureteropelvic junction obstruction.
more medially and caudally in the bladder than the ureter from the
lower pole (Weigert–Meyer rule). This reflects the embryological devel-
Fig. 74.26 A–B, Sagittal grey-scale ultrasound images through the
opment of the ureter: the ureteric bud that is initially more proximal pelvis of a 2-day-old girl demonstrate a dilated left ureter, which
on the mesonephric duct has a shorter time to be pulled cranially in contains layering echogenic debris, and an anechoic round filling
the bladder and so it inserts more distally in the mature bladder. The defect in the inferior bladder with increased through-transmission
ureter from the lower pole has a shorter intramural course than the and an echogenic rim, in keeping with a ureterocele.
longer ureter and is prone to reflux.
Fig. 74.27 An intravenous urogram showing a classic retrocaval (or
Ectopic ureters Single ureters, and, more commonly, the longer circumcaval) ureter.
ureter of a duplex system, can insert more caudally and medially than
KEY REFERENCES
Brödel M 1911 The intrinsic blood-vessels of the kidney and their signifi- An early paper describing the identification of pacemaker cells in various
cance in nephrotomy. Bull Johns Hopkins Hosp 12:10–13. species.
The original description of a relatively avascular longitudinal zone within
Merklin RJ, Michels NA 1958 The variant renal and suprarenal blood supply
the kidney, proposed as a site for surgical incision.
with data on the inferior phrenic, ureteral, and gonadal arteries: a sta-
Burkhill GJ, Healy JC 2000 Anatomy of the retroperitoneum. Imaging 12: tistical analysis based on 185 dissections and a review of the literature.
10–20. J Int Coll Surg 29:41–76.
A review of the imaging literature describing the contentious anatomy of the A review of renal vascular anatomy in almost 11,000 kidneys.
perirenal fascia.
Mitchell GA 1950 The renal fascia. Br J Surg 37:257–66.
Gosling JA, Dixon JS 1974 Species variation in the location of upper urinary An account that demonstrates that the perirenal fascia is a multilaminar
tract pacemaker cells. Invest Urol 11:418. structure rather than a single fused fascia. | 1,731 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
1254.e1
47
retPaHC
B 4
U
1
2
A
3
B
U
Fig. 74.27 An intravenous urogram showing a classic retrocaval (or
circumcaval) ureter. A degree of obstruction has resulted in a markedly
dilated upper ureter. The ureter passes cranially, medially and then
caudally, and can be followed into the pelvis. Key: 1, contrast within
B dilated collecting system of right kidney and upper ureter; 2, contrast
within ureter turning behind inferior vena cava; 3, contrast within normal
Fig. 74.26 A–B, Sagittal grey-scale ultrasound images through the pelvis calibre ureter seen below the obstruction; 4, contrast within normal
of a 2-day-old girl demonstrate a dilated left ureter (U), which contains collecting system of left kidney and upper ureter.
layering echogenic debris, and an anechoic round filling defect (*) in the
inferior bladder (B) with increased through-transmission and an echogenic
rim, in keeping with a ureterocele. | 1,732 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Kidney and ureter
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REFERENCES
Brödel M 1911 The intrinsic blood-vessels of the kidney and their signifi- tistical analysis based on 185 dissections and a review of the literature.
cance in nephrotomy. Bull Johns Hopkins Hosp 12:10–13. J Int Coll Surg 29:41–76.
The original description of a relatively avascular longitudinal zone within A review of renal vascular anatomy in almost 11,000 kidneys.
the kidney, proposed as a site for surgical incision.
Mitchell GA 1950 The renal fascia. Br J Surg 37:257–66.
Burkhill GJ, Healy JC 2000 Anatomy of the retroperitoneum. Imaging 12: An account that demonstrates that the perirenal fascia is a multilaminar
10–20. structure rather than a single fused fascia.
A review of the imaging literature describing the contentious anatomy of the
Novick AC 1998 Anatomic approaches in nephron-sparing surgery for renal
perirenal fascia.
cell carcinoma. Atlas Urol Clin North Am 6:39.
Davies A, Blakeley AG, Kidd C 2001 The renal system. In: Human Physiol- Ramage IJ, Howatson AG, McColl JH et al 2002 Glomerular basement
ogy. Edinburgh: Elsevier, Churchill Livingstone; Ch. 8, pp. 713–97. membrane thickness in children: a stereologic assessment. Kidney Int
Davies JM 1991 The role of the efferent arteriole in tubuloglomerular feed- 62:895–900.
back. Kidney Int Suppl 32:S71–3. Schneider A, Ferreira CG, Delay C et al 2013 Lower pole vessels in children
Gosling JA, Dixon JS 1974 Species variation in the location of upper urinary with pelviureteric junction obstruction: laparoscopic vascular hitch or
tract pacemaker cells. Invest Urol 11:418. dismembered pyeloplasty? J Pediatr Urol 9:419–23.
An early paper describing the identification of pacemaker cells in various Scott JE 2002 Fetal, perinatal, and infant death with congenital renal
species. anomaly. Arch Dis Child 87:114–17.
Madias NE, Adrogué HJ 2005 Hypo-hypernatraemia: disorders of water Singh P, Thomson SC 2011 Renal homeostasis and tubuloglomerular feed-
balance. In: Davison AM, Cameron JS, Grunfeld J-P et al (eds) Oxford back. Curr Opin Nephrol Hypertens 19:59–64.
Textbook of Clinical Nephrology. Oxford: Oxford University Press; Tannen RL, Hallows KR 2005 Hypo-hyperkalaemia. In: Davison AM,
Ch. 2.1, vol. 1. Cameron JS, Grunfeld J-P et al (eds) Oxford Textbook of Clinical Neph-
Manalich R, Reyes L, Herrera M et al 2000 Relationship between weight at rology. Oxford: Oxford University Press; Ch. 2.2, vol. 1.
birth and the number and size of renal glomeruli in humans: a histo- Veyrac C, Baud C, Lopez C et al 2003 The value of colour Doppler ultra-
morphometric study. Kidney Int 58:770–3. sonography for identification of crossing vessels in children with pelvi-
Merklin RJ, Michels NA 1958 The variant renal and suprarenal blood supply ureteric junction obstruction. Pediatr Radiol 33:745–51.
with data on the inferior phrenic, ureteral, and gonadal arteries: a sta- | 1,733 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
CHAPTER
75
Bladder, prostate and urethra
umbilical ligament (urachus) ascends behind the anterior abdominal
URINARY BLADDER
wall from the apex to the umbilicus, covered by peritoneum to
form the median umbilical fold (Fig. 75.3, see Fig. 72.19) (see below
The urinary bladder is a reservoir. Its size, shape, position and relations and p. 1077).
all vary, according to its content and the state of the neighbouring The anterior surface of the bladder is separated from the transversalis
viscera. When the bladder is empty, it lies entirely in the lesser pelvis, fascia by adipose tissue in the potential retropubic space (of Retzius)
but as it distends, it expands anterosuperiorly into the abdominal cavity (Fig. 75.4). This is more adherent to the bladder than to the anterior
(Video 75.1). An empty bladder is somewhat tetrahedral and has a base surface of the prostate, which aids reliable identification of the region
(fundus), neck, apex, and a superior (dome) and two inferolateral of the bladder neck surgically. In males, each inferolateral surface is
surfaces. related anteriorly to the pubis and puboprostatic ligaments. In females,
the relations are similar, except that the pubovesical ligaments replace
the puboprostatic ligaments. The inferolateral surfaces are not covered
RELATIONS by peritoneum. The triangular superior surface is bounded by lateral
borders from the apex to the ureteric entrances, and by a posterior
The base of the bladder is triangular and located posteroinferiorly. In border that joins them. In males, the superior surface is completely
females, it is closely related to the anterior vaginal wall (Fig. 75.1); in covered by peritoneum, which extends slightly on to the base and con-
males, it is related to the rectum, although it is separated from it supe- tinues posteriorly into the rectovesical pouch and anteriorly into the
riorly by the rectovesical pouch, and inferiorly by the seminal vesicle median umbilical fold; it is in contact with the sigmoid colon and
and vas (ductus) deferens on each side, and by Denonvilliers’ fascia the terminal coils of the ileum (see Fig. 75.2). In females, the superior
(Fig. 75.2). The neck, which is most fixed, lies most inferiorly, 3–4 cm surface is largely covered by peritoneum, which is reflected posteriorly
behind the lower part of the pubic symphysis and just above the plane on to the uterus at the level of the internal os (the junction of the
of the inferior aperture of the lesser pelvis. The bladder neck is, essen- uterine body and cervix), to form the vesicouterine pouch. The posterior
tially, the internal urethral orifice, which lies in a constant position part of the superior surface, devoid of peritoneum, is separated from
that is independent of the varying positions of the bladder and rectum. the supravaginal cervix by fibroareolar tissue.
In males, the neck rests on, and is in direct continuity with, the base These relationships are important in managing bladder trauma.
of the prostate; in females, it is related to the pelvic fascia that Extraperitoneal injuries can often be managed conservatively because
surrounds the upper urethra. In both sexes, the apex of the bladder urine is contained, whereas intraperitoneal injuries usually require sur-
faces towards the upper part of the pubic symphysis. The median gical repair.
Fig. 75.1 The relations of the
female bladder, sagittal section of
the pelvis. (With permission from
Ureter
Waschke J, Paulsen F (eds),
Sigmoid colon Sobotta Atlas of Human
Anatomy, 15th ed, Elsevier,
External iliac artery and vein Urban & Fischer. Copyright 2013.)
Ovarian follicles
Uterine fundus
Rectal ampulla
Inferior epigastric artery and vein
Parietal peritoneum
Linea alba
Recto-uterine pouch
Median umbilical
ligament
Cervix
Internal urethral
orifice
Rectovaginal fascia
Corpus cavernosum
clitoris
Frenulum of clitoris Ureteric orifice
Labium minor
External urethral orifice
Labium majus
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Bladder, prostate and urethra
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A
Sigmoid colon
Internal urethral meatus
Ureteric orifice
Small intestine
Median umbilical ligament
Retropubic space
(of Retzius)
Rectovesical pouch
Linea alba
Pubic symphysis Rectal ampulla
Suspensory ligament of penis Denonvilliers’s fascia
Deep dorsal vein of penis Prostate
Visceral pelvic fascia
Dorsal vein of penis Anococcygeal ligament
External anal sphincter
Internal anal sphincter
Deep transverse perineal muscle
Perineal membrane
Membranous urethra
Bulb of penis
Parietal
peritoneum
Full bladder
Parietal
peritoneum
Rectum
Empty
bladder
Rectum Prostate
Prostate
Fig. 75.2 A, The relationship of the bladder and prostate: sagittal section, male pelvis. The relationship of the bladder to the peritoneum and anterior
abdominal wall on filling allows suprapubic cystostomy without intraperitoneal urinary leak. ( With permission from Waschke J, Paulsen F (eds), Sobotta
Atlas of Human Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
Continued
As the bladder fills, it becomes ovoid (Fig. 75.5; see Fig. 75.2 and between the summit and the anterior abdominal wall; this recess often
Video 75.1). Anteriorly, it displaces the parietal peritoneum from the contains coils of small intestine. At birth, the bladder is higher than in
suprapubic region of the abdominal wall. Its inferolateral surfaces the adult because the true pelvis is shallow, and the internal urethral
become anterior and rest against the abdominal wall without interven- orifice is level with the upper symphysial border. The bladder is then
ing peritoneum for a distance above the pubic symphysis that varies abdominal rather than pelvic, and extends about two-thirds of the
with the degree of distension, but is commonly 5–7 cm. The distended distance towards the umbilicus.
bladder may be punctured just above the pubic symphysis without
traversing the peritoneum (suprapubic cystostomy) (see Fig. 75.2); sur-
gical access to the bladder through the anterior abdominal wall is LIGAMENTS OF THE BLADDER
usually by this route. The summit of the full bladder points up and
forwards above the attachment of the median umbilical ligament, so The bladder is anchored inferiorly to the pubis, lateral pelvic side
that the peritoneum forms a supravesical recess of varying depth walls and rectum by condensations of pelvic fascia; although these | 1,735 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Bladder, prostate and urethra
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retpahC
Urine samples may, therefore, be obtained in children by performing 1300.00
97
suprapubic needle puncture. A normogram of bladder volume index 95
90
(BVI = length × width × depth of bladder), based on sonographic meas- 1200.00 75
50
urements in children, is shown in Figure 75.6. The bladder progres-
1100.00 25
sively descends with growth, and reaches the adult position shortly after 10
5
puberty. 1000.00 3
900.00
800.00
700.00
600.00
500.00
400.00
300.00
200.00
100.00
0.00
0 1 2 3 4 5 6 7 8 9 10
Age (years)
Fig. 75.6 Centiles of bladder volume index in children. (Redrawn with
permission from Leung VY, Chu WC, Yeung CK et al Nomograms of total
renal volume, urinary bladder volume and bladder wall thickness index in
3,376 children with a normal urinary tract, Pediatric Radiology (2007);
37:181–188.)
)3mc(
)IVB(
xedni
emulov
reddalB
11 12 13 14 15 16 17 18 19 | 1,736 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
urinary bladder
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Rectus abdominis Bladder Seminal vesicle Left lateral border of perivesical fat Left medial umbilical ligament
(entrance to space of Retzius) (obliterated umbilical artery)
Median umbilical
ligament (urachus)
Right medial
umbilical ligament
(obliterated
umbilical artery)
Urinary bladder
A
Left lateral border of perivesical fat Left medial umbilical ligament Median umbilical
(entrance to space of Retzius) (left obliterated umbilical artery) ligament (urachus)
B
Body of pubis Corpus Bulb of penis Prostate Rectum
cavernosum Origin of left
Fig. 75.2, cont’d B, A sagittal T2-weighted magnetic resonance image of inferior epigastric
the male pelvis, showing the bladder, prostate and relations. vessels
Left gonadal
vessels
condensations are not true anatomical ligaments, the term is applied
in routine clinical use (see p. 1224 for a further description of the vis-
ceral pelvic fascia).
In both sexes, stout bands of fibromuscular tissue, the pubovesical
ligaments, extend from the bladder neck to the inferior aspect of the B
pubic bones; they lie on each side of the median plane, leaving a
midline hiatus through which numerous small veins pass. The pubo-
Left vas deferens Peritoneum covering bladder dome
vesical ligaments are derived from the detrusor muscle, part of the
detrusor apron (Fig. 75.7). In the female, they constitute the superior Fig. 75.3 A, A view of the midline anterior abdominal wall and ligaments
extensions of the pubourethral ligaments. In the male, the detrusor during laparoscopy. B, A view of the left side of the anterior abdominal
wall and ligaments during laparoscopy.
apron is described as an extension of detrusor that extends over the
anterior surface of the prostate, and condenses distally and anteriorly
to form the puboprostatic ligaments.
Other ligaments that have been described in relation to the base of BLADDER INTERIOR
the urinary bladder are the lateral, sacrogenital/uterosacral and cardinal
ligaments. The literature is sometimes confusing and even contradic- Vesical mucosa
tory. The lateral ligament was described by Miles in 1908; although Almost all of the vesical mucosa (Fig. 75.10) is attached only loosely
never described in anatomical cadaveric dissection studies, it is recog- to subjacent muscle; it folds when the bladder empties, and the folds
nized clinically as an important structure in the pararectal space at are stretched flat as it fills. Over the trigone, immediately above and
operation. It is a broad band of dense connective tissue, varying in behind the internal urethral orifice, it is adherent to the subjacent
depth from 5 to 7 cm, and passing between the lateral wall of the pelvis muscle layer and is always smooth. The anteroinferior angle of the
and the base of the bladder at the point where the ureter terminates. It trigone is formed by the internal urethral orifice, its posterolateral
contains the middle rectal artery and lymphatic vessels that pass from angles by the ureteric orifices. The superior trigonal boundary is a
the lower rectum to the iliac lymph nodes (Takahashi et al 2000). The slightly curved inter-ureteric bar, which connects the two ureteric ori-
apex of the bladder is connected to the umbilicus by the remains of the fices and is produced by the continuation into the vesical wall of the
urachus, which forms the median umbilical ligament (see Fig. 75.3; ureteric internal longitudinal muscle. Laterally, this ridge extends
Video 75.2). Composed of longitudinal muscle fibres derived from the beyond the ureteric openings as ureteric folds, produced by the terminal
detrusor, it becomes more fibrous towards the umbilicus. It usually parts of the ureters, which run obliquely through the bladder wall. At
maintains a lumen lined with epithelium that persists into adult life cystoscopy, the inter-ureteric crest appears as a pale band and is a guide
but is only rarely complicated by a urachal cyst, sinus, fistula or to the ureteric orifices (Fig. 75.10B).
adenocarcinoma.
Trigone
From the superior surface of the bladder, the peritoneum is carried
off in a series of folds: the ‘false’ ligaments of the bladder. Anteriorly, The smooth muscle of the trigone consists of two distinct layers, some-
there are three folds (Fig. 75.8): the median umbilical fold over the times termed the superficial trigonal muscle and deep trigonal detrusor
median umbilical ligament (urachus), and two medial umbilical folds muscle. The latter is composed of muscle cells, indistinguishable from
over the obliterated umbilical arteries. The inferior epigastric vessels those of the detrusor, and is simply the posteroinferior portion of the
(Fig. 75.9) are lateral to these folds on the anterior abdominal wall and detrusor muscle proper. The superficial trigonal muscle represents a
are termed lateral umbilical ligaments in descriptions of anterior morphologically distinct component of the trigone, which, unlike the
abdominal wall anatomy. detrusor, is composed of relatively small-diameter muscle bundles that | 1,737 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Bladder, prostate and urethra
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The urachus may play a critical role in maintaining fetal life when Left inferior epigastric vessels Left medial umbilical ligament Urinary bladder
atresia of the urethra results in complete obstruction to the flow of
amniotic fluid. Anhydramnios noted at 17 weeks’ gestation has been
reported to resolve by 21 weeks when the patent urachus acts as a fistula
between the bladder and the amniotic space, preserving pulmonary and
renal function (Stalberg and Gonzalez 2012).
Left medial umbilical ligament Median umbilical ligament
Left testicular vessels
Fig. 75.9 A laparoscopic view of the left inferior epigastric vein (lateral
umbilical ligament) in a 12-month-old boy. (Courtesy of Mr Girish
Jawaheer.)
Urinary bladder Right medial umbilical ligament
Fig. 75.8 A laparoscopic view of the empty bladder and median and
medial umbilical folds in a 12-month-old boy. (Courtesy of Mr Girish
Jawaheer.) | 1,738 | 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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Left superior Endopelvic Left puboprostatic Dorsal venous
A
pubic ramus fascia ligament complex
Bladder
Pubis
Fibres of detrusor
muscle
Urethra
Striated urethral sphincter
Striated urethral meatus
Pubovesical ligament
B
Bladder
Detrusor apron
Bladder (released from Prostate
Seminal
the anterior abdominal wall)
vesicle
Fig. 75.4 A transperitoneal view of the male pelvis, as seen during
robotic-assisted laparoscopic radical prostatectomy. The bladder is
released from the anterior abdominal wall, the space of Retzius is Pubis
developed and the endopelvic fascia opened.
Prostate
Medial umbilical ligament (obliterated umbilical artery)
Striated urethral sphincter
Bulb of penis
Puboprostatic (pubovesical) ligament
Location of
seminal Fig. 75.7 Ligaments that anchor the neck of the bladder and pelvic part
vesicles and of the urethra to the pelvic bone. A, In the female. B, In the male. In
vas deferens males, the detrusor extends over the anterosuperior aspect of the
prostate and inserts into the pubic bone. It condenses to form
pubovesical/puboprostatic ligaments. (A–B, With permission from Drake
Tip of
Foley RL, Vogl AW, Mitchell A, Tibbitts R, Richardson P (eds), Gray’s Atlas of
catheter Anatomy, Elsevier, Churchill Livingstone. Copyright 2008.)
Rectovesical unit. The arrangement of smooth muscle in this region is quite different
pouch in males and females, and therefore will be described separately.
Female
Left Right In the female, the bladder neck consists of morphologically distinct
smooth muscle (Fig. 75.10C). The large-diameter fasciculi characteristic
Fig. 75.5 Laparoscopic view of the full bladder.
of the detrusor are replaced in the region of the bladder neck by small-
diameter fasciculi that extend obliquely or longitudinally into the ure-
are continuous proximally with those of the intramural ureters. The thral wall. In the normal female, the bladder neck sits above the pelvic
superficial trigonal muscle is relatively thin but is generally described floor, supported predominantly by the pubovesical ligaments (see Fig.
as becoming thickened along its superior border to form the interuret- 75.7A), the endopelvic fascia of the pelvic floor and levator ani. These
eric ridge (bar). Similar thickenings occur along the lateral edges of support the urethra at rest; with elevated intra-abdominal pressure, the
the superficial trigone. In both sexes, the superficial trigone muscle levators contract, increasing urethral closure pressure to maintain con-
becomes continuous with the smooth muscle of the proximal urethra, tinence. This anatomical arrangement commonly alters after parturition
and extends in the male along the urethral crest as far as the openings and with increasing age, such that the bladder neck lies beneath the
of the ejaculatory ducts. pelvic floor, particularly when intra-abdominal pressure rises, which
means that the mechanism described above fails to maintain conti-
Ureteric orifices nence and women may experience stress incontinence (Klutke and
The slit-like ureteric orifices are placed at the posterolateral trigonal Siegel 1995).
angles (Fig. 75.10A,B). In empty bladders, they are approximately
Male
2.5 cm apart, and 2.5 cm from the internal urethral orifice; in disten-
sion, these measurements may be doubled. In the male, the bladder neck is completely surrounded by a circular
collar of smooth muscle, with its own distinct adrenergic innervation,
Internal urethral orifice which extends distally to surround the preprostatic portion of the
The internal urethral orifice is sited at the trigonal apex, the lowest part urethra. These smooth muscle bundles are distinct from the smooth
of the bladder, and is usually somewhat crescentic in section. There is muscle bundles that run in continuity from the bladder neck down to
often an elevation immediately behind it in adult males (particularly the prostatic urethra, and from the smooth muscle within the prostate.
past middle age), which is caused by the median prostatic lobe. The bundles that form this ‘preprostatic sphincter’ are small in size
compared with the muscle bundles of the detrusor, and are separated
by a relatively larger connective tissue component rich in elastic fibres.
BLADDER NECK The bladder neck is sometimes called the proximal or internal
sphincter mechanism, to distinguish it from the distal urinary sphincter
The smooth muscle of the bladder neck is histologically, histochemi- mechanism. The internal sphincter contributes to urinary continence
cally and pharmacologically distinct from the detrusor muscle proper and, in the face of distal sphincteric incompetence, can, at times, main-
and so the bladder neck should be considered as a separate functional tain continence independently. Unlike the detrusor and the rest of the | 1,739 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
urinary bladder
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Median umbilical ligament
A B
Bladder mucosa
Muscular layer (muscular coat)
Mucosa (mucous membrane)
Interureteric bar Ureteric orifice
C
Internal
Bladder urethral sphincter
(lissosphincter)
Urethra
Ureteric orifice
Interureteric ridge Mucosal folds
External
Uvula of bladder Trigone urethral sphincter
(rhabdosphincter)
Urethral crest Internal urethral meatus
(bladder neck)
Prostatic sinus
Prostatic Prostatic Prostate
urethra utricle
Verumontanum Prostatic ducts
(seminal
colliculus) Ejaculatory
ducts
Fig. 75.10 A, A coronal section of the urinary bladder in the male. The mucosal folds are dependent on the state of filling. B, The ureteric orifice seen at
endoscopy. C, A posterior view of the bladder neck in the female. (A, With permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human
Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
urethral smooth muscle (common to both sexes), the preprostatic Inferior vesical artery
sphincter is richly supplied with sympathetic noradrenergic nerves and
The inferior vesical artery often arises with the middle rectal artery from
is almost totally devoid of parasympathetic cholinergic nerves (see
the internal iliac artery. It supplies the base of the bladder, prostate,
below).
seminal vesicles and lower ureter, and may sometimes provide the
artery to the vas deferens. Prostatic branches communicate across the
Bladder outflow obstruction
midline.
In progressive chronic obstruction to micturition, e.g. as a result of
prostatic enlargement or urethral stricture, or in children with congeni-
Veins
tal bladder outflow obstruction, e.g. posterior urethral valves, the
muscle of the bladder hypertrophies. The muscle fasciculi increase in
size and, because they interlace in all directions, a thick-walled ‘trabecu- The veins that drain the bladder form a complicated plexus on its infe-
lated bladder’ is produced. Mucosa between the fascicles forms ‘diver- rolateral surfaces and pass backwards in the lateral ligaments of the
ticula’. When outflow is obstructed, emptying is not complete; some bladder to end in the internal iliac veins (see Fig. 77.3).
urine remains and may become infected. Back-pressure from a chroni-
cally distended bladder may gradually dilate the ureters, renal pelves Lymphatic drainage
and even the renal collecting tubules, which can result in progressive
renal impairment. Lymphatics that drain the bladder begin in mucosal, intermuscular and
serosal plexuses (see Fig. 77.3). There are three sets of collecting vessels;
most end in the external iliac nodes. Vessels from the trigone emerge
VASCULAR SUPPLY AND LYMPHATIC DRAINAGE on the exterior of the bladder to run superolaterally. Vessels from the
superior surface of the bladder converge to the posterolateral angle and
Arteries pass superolaterally to the external iliac nodes (some may go to the
internal or common iliac group). Vessels from the inferolateral surface
The bladder is supplied principally by the superior and inferior vesical of the bladder ascend to join those from the superior surface or run to
arteries (see Figs 77.3, 74.22), derived from the anterior trunk of the the lymph nodes in the obturator fossa. Minute nodules of lymphoid
internal iliac artery, and supplemented by the obturator and inferior tissue may occur along the vesical lymph vessels.
gluteal arteries. In the female, additional branches are derived from the
uterine and vaginal arteries.
INNERVATION
Superior vesical artery
The superior vesical artery supplies many branches to the fundus of the The nerves supplying the bladder arise from the pelvic plexuses, a mesh
bladder. The artery to the vas deferens often originates from one of these of autonomic nerves and ganglia lying on the lateral aspects of the
and accompanies the vas deferens to the testis, where it anastomoses rectum, internal genitalia and bladder base (Fig. 75.11). They consist
with the testicular artery. Other branches supply the ureter. The initial of both sympathetic and parasympathetic components, each of which
portion of the superior vesical artery is the proximal, patent, section of contains both efferent and afferent fibres. For further reading, see
the fetal umbilical artery. Mundy et al (1999a). | 1,740 | 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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Paravertebral sympathetic chain
Coeliac plexus T12
Inferior mesenteric plexus
Superior hypogastric plexus
L5
Ureter Hypogastric nerve S1
Vas deferens
Urinary bladder
Pelvic splanchnic
Seminal vesicle nerves
Sciatic nerve
Puboprostatic ligament
Prostate
Pelvic (inferior hypogastric) plexus
Striated urethral
Pudendal nerve
sphincter
Inferior rectal nerve
Perineal nerve
Dorsal nerve of penis
Fig. 75.11 Innervation of the lower urinary tract and male genitalia. (Redrawn with permission from Dyck P, Thomas PK, 2005, Peripheral Neuropathy,
Saunders, Elsevier.)
Efferent fibres considered to typify cholinergic nerve terminals, and contain clusters
Parasympathetic fibres arise from the second to the fourth sacral seg- of small (50 nm diameter) agranular vesicles, occasional large
ments of the spinal cord and enter the pelvic plexuses on the postero- (80–160 nm diameter) granulated vesicles and small mitochondria.
lateral aspects of the rectum as the pelvic splanchnic nerves. The Terminal regions approach to within 20 nm of the surface of the muscle
sympathetic fibres are derived from neuronal cell bodies in the lower cells and may be partially surrounded by Schwann cell cytoplasm; more
three thoracic and upper two lumbar segments of the spinal cord and often, they are naked nerve endings. The human detrusor muscle pos-
form the coeliac and mesenteric plexuses around the great vessels in the sesses a sparse but definite supply of sympathetic noradrenergic nerves
abdomen; from here, the hypogastric plexuses descend into the pelvis that generally accompany the vascular supply and only rarely extend
as fairly discrete nerve bundles within the extraperitoneal connective among the myocytes. Non-adrenergic, non-cholinergic nerves have
tissue posterior to the ureter on each side. The anterior part of the pelvic been identified, and a number of other neurotransmitters or neuro-
plexus is known as the vesical plexus. Small groups of autonomic neu- modulators have been detected in intramural ganglia, including the
rones occur within the plexus and throughout all regions of the bladder peptide somatostatin. The superficial trigonal muscle is associated with
wall. These multipolar intramural neurones are rich in acetylcholinester- more noradrenergic (sympathetic) fibres than cholinergic (parasympa-
ase (AChE) and occur in ganglia consisting of up to 20 neuronal cell thetic) nerves, a difference that supports the view that the superficial
bodies. The majority of the preganglionic nerve terminals correspond trigonal muscle should be regarded as ‘ureteric’ rather than ‘vesical’ in
morphologically to presumptive cholinergic fibres. Noradrenergic ter- origin. It is, however, important to emphasize that the superficial trigo-
minals also relay on cell bodies in the pelvic plexus; it is not known nal muscle forms a very minor part of the total muscle mass of the
whether similar nerves synapse on intramural bladder ganglia. bladder neck and proximal urethra in either sex and is probably of little
The urinary bladder (including the trigonal detrusor muscle) is pro- significance in the physiological mechanisms that control these regions.
fusely supplied with nerves, which form a dense plexus among the The smooth muscle of the bladder neck in males is predominantly
detrusor muscle cells. The majority of these nerves contain AChE and orientated obliquely or circularly. It is sparsely supplied with cholin-
occur in abundance throughout the muscle coat of the bladder. Axonal ergic (parasympathetic) nerves but possesses a rich noradrenergic (sym-
varicosities adjacent to detrusor muscle cells possess features that are pathetic) innervation. A similar distribution of autonomic nerves also | 1,741 | 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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occurs in the smooth muscle of the prostate gland, seminal vesicles and bladder. This layer is often very superficial, lying close beneath the
vasa deferentia. Stimulation of sympathetic nerves causes contraction urothelium, but is sometimes deeper in the lamina propria, where it
of smooth muscle in the wall of the genital tract, resulting in seminal may be well developed; it must be distinguished from the muscularis
emission. Concomitant sympathetic stimulation of the proximal ure- propria. Several functions have been proposed for the lamina propria,
thral smooth muscle causes sphincteric closure of the preprostatic including acting as the capacitance layer of the bladder (determining
sphincter, thereby preventing reflux of ejaculate into the bladder. bladder compliance and enabling adaptive changes to increasing
It is extensively disrupted in the vast majority of men undergoing volumes); providing factors that influence the growth of the urothelium
bladder neck surgery, e.g. transurethral resection of the prostate, which and/or detrusor; and playing a role in signal transduction (Andersson
may result in retrograde ejaculation. Similarly, anejaculation can result and McCloskey 2014).
when the sympathetic fibres are disrupted during retroperitoneal lymph
node dissection surgery. Interstitial cells of Cajal-like cells
Although this genital function of the bladder neck of the male is Interstitial cells of Cajal (ICC) are a specialized population of cells
well established, it is not known whether the smooth muscle of this involved in smooth muscle excitability that were initially described in
region plays an active role in maintaining urinary continence. In con- the gastrointestinal tract (p. 1043). Cells with a similar morphology but
trast, the smooth muscle of the bladder neck of the female receives rela- expressing platelet-derived growth receptor alpha (PDGFRα), rather
tively few noradrenergic nerves but is richly supplied with presumptive than the tyrosine kinase receptor Kit that typifies ICC, and therefore
cholinergic fibres. The sparse supply of sympathetic nerves presumably designated interstitial cells of Cajal-like cells (ICC-LC), have been
relates to the absence of a functioning ‘genital’ portion of the wall of reported in the urethra, vas deferens, prostate, bladder, corpus caverno-
the female urethra. sum, ureter, Fallopian tube, oviduct and uterus, where they form a
The lamina propria of the fundus and inferolateral walls of the functional syncytium with nerves and smooth muscle cells. They may
bladder is virtually devoid of autonomic nerve fibres, apart from some function as electrical pacemakers in the urethra and prostate. In the
noradrenergic and occasional presumptive cholinergic perivascular bladder, they are found closely apposed to detrusor smooth muscle
nerves. However, the density of nerves unrelated to blood vessels cells, in the lamina propria and within the suburothelium; it has been
increases closer to the urethral orifice. At the bladder neck and trigone, tentatively suggested that one of their functions in the bladder is to act
a nerve plexus of cholinesterase-positive axons extends throughout the as intermediary cells transducing nerve signals to detrusor smooth
lamina propria, independent of blood vessels. Some of the larger- muscle cells (Drumm et al 2014).
diameter axons are myelinated and others lie adjacent to the basal
Muscularis propria
urothelial cells. In the absence of any obvious effector target sites, the
subepithelial nerve plexuses of the bladder and the ureter are assumed The muscularis propria is the detrusor muscle of the bladder wall. It
to subserve a sensory function. consists of three indistinct layers: an inner and outer longitudinal, and
an intermediate circular layer. In contrast to the muscularis mucosae,
Afferent fibres which consists of small wispy fibres, the muscularis propria is made up
Vesical nerves are also concerned with pain and awareness of distension, of larger, poorly defined, bundles of smooth muscle that form well-
and are stimulated by distension or spasm due to a stone, inflammation defined inner circular and outer longitudinal layers at the neck of the
or malignant disease; they travel in sympathetic and parasympathetic bladder.
nerves, but predominantly in the latter. Division of the sympathetic
Serosa
paths (e.g. ‘presacral neurectomy’) or of the superior hypogastric plexus,
therefore, does not materially relieve vesical pain, whereas considerable The serosa partially covers the bladder. It is lined externally by mesothe-
relief follows bilateral anterolateral cordotomy. Since nerve fibres medi- lium, beneath which there is a variable amount of vascularized adipose
ating awareness of distension travel in the posterior columns (fasciculus tissue that frequently extends into the muscularis propria and, occasion-
gracilis), the patient still retains awareness of the need to micturate after ally, into the lamina propria.
anterolateral cordotomy. The nerve endings detecting noxious stimuli
are probably of more than one type; a subepithelial plexus of fibres
MALE URETHRA
containing dense vesicles, which are probably afferent endings, has
been described.
The male urethra (Fig. 75.12, see Fig. 75.2) is 18–20 cm long, and extends
from the internal orifice in the urinary bladder to the external opening,
MICROSTRUCTURE
or meatus, at the end of the penis. It may be considered in two parts. The
anterior urethra is approximately 16 cm long and lies within the peri-
The bladder consists of four layers: a lining epithelium (urothelium), neum (proximally) and the penis (distally), surrounded by the corpus
lamina propria, muscularis propria and serosa. spongiosum. The posterior urethra is 4 cm long and lies in the pelvis
proximal to the corpus spongiosum, where it is acted on by the urogenital
Lining epithelium or urothelium sphincter mechanisms. Functionally, both parts act as a conduit.
Urothelium (transitional epithelium; see Fig. 2.5D) is 4–7 cells thick; The anterior urethra is subdivided into a proximal component, the
it may appear to be attenuated to 2–3 cells thick when the bladder is bulbar urethra, which is surrounded by bulbospongiosus and entirely
fully distended. It contains three distinctive cell layers: a basal layer, an within the perineum, and a pendulous or penile component, which
intermediate layer and a superficial (‘umbrella’ cell) layer (see Fig. continues to the tip of the penis. The posterior urethra is divided into
75.15). The basal layer consists of small cuboidal cells from which the preprostatic, prostatic and membranous segments. In the flaccid penis,
upper layers arise. The intermediate layers are polygonal and possess the urethra has a double curve. The urethral canal is a mere slit, except
the capacity to stretch and flatten. The superficial layer forms a protec- during the passage of fluid; in transverse section, it is transversely arched
tive, almost impermeable, surface for the bladder mucosa and consists in the prostatic part, stellate in the preprostatic and membranous por-
of large, sometimes multinucleated, cells displaying degenerative tions, transverse in the bulbar and penile portions, and sagittal at the
changes in their cytoplasm; these cells are ultimately exfoliated into the external orifice.
urine. The apical surface of the umbrella cell layer is covered by 16 nm
Posterior part
protein particles packed hexagonally to form two-dimensional crystals
of asymmetric unit membranes (AUMs), which contribute to the per- preprostatic urethra
meability barrier function of the urinary bladder, preventing reabsorp- The preprostatic urethra is approximately 1 cm in length, and extends
tion of urine across the urothelium into the blood stream. Islands or from the base of the bladder to the prostate (Fig. 75.12). Small peri-
nests of urothelium (von Brunn’s nests) may become separated from urethral glands at this site may contribute to benign prostatic hyperpla-
the surface during development and are found embedded in the under- sia (BPH) and symptoms of outflow obstruction in older men.
lying lamina propria; they may undergo central degeneration to form
cysts (cystitis cystica). prostatic urethra
The prostatic urethra is 3–4 cm in length and tunnels through the
Lamina propria
substance of the prostate, closer to the anterior than the posterior
The lamina propria forms a connective tissue bed supporting the overly- surface of the gland (Fig. 75.13; see Fig. 75.10). It is continuous above
ing urothelium, from which it is separated by a basement membrane. with the preprostatic part and emerges from the prostate slightly ante-
It is rich in capillaries, lymphatics and nerve endings, and contains rior to its apex (the most inferior point of the prostate). Throughout
elastic fibres and a thin, poorly defined, layer of smooth muscle fibres, most of its length, the posterior wall possesses a midline ridge, the
the muscularis mucosae, which is variably distributed within the urethral crest, that projects into the lumen, causing it to appear | 1,742 | 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
Bladder mucosa –
base of bladder
Fundus
Left ureteral
Interureteric ridge orifice
Mucosal folds
Trigone
Trigone
Left lateral
bladder neck
Ureteral orifice
Uvula of bladder Posterior
Internal urethral bladder
meatus (bladder neck) neck
Preprostatic urethra
Seminal colliculus Left lateral
(verumontanum) lobe of
prostate
Prostatic urethra Ejaculatory ducts Prostatic utricle
Prostatic ducts
Urethral crest
Urethral crest
Prostatic
Membranous urethra Bulbourethral gland Bulb of penis sinus
and duct
Crus of penis Verumontanum
Prostatic utricle
Bulbourethral glands
Urethral crest and
verumontanum
Mucosal folds of
external urethral
sphincter mechanism
Male urethra Bulbar urethra
Corpus spongiosum
Membranous
urethra
Bulbar urethra
Penile urethra
Corpus cavernosum
Penile urethra
Urethral lacunae
Urethral lacuna
Penile urethra
Glans penis
Navicular fossa
Prepuce
External urethral
meatus (orifice) Navicular fossa
Fig. 75.12 A, The male urethra. B, Endoscopic views (top to bottom): posterior bladder wall and trigone, bladder neck, urethral crest, membranous
urethra, bulbar urethra, penile urethra, navicular fossa. (A, with permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed,
Elsevier, Urban & Fischer. Copyright 2013.)
crescentic in transverse section. On each side of the crest, the floor of a Membranous urethra
shallow depression, the prostatic sinus, is perforated by the orifices of The membranous part of the urethra is the shortest (2–2.5 cm), least
15–20 prostatic ducts. An elevation, the verumontanum (seminal col- dilatable and, with the exception of the external orifice, the narrowest
liculus), occurs at about the middle of the length of the urethral crest; section of the urethra. It descends with a slight ventral concavity from
at this point, the urethra turns anteriorly and contains the slit-like the prostate to the bulb of the penis, passing through the perineal
orifice of the prostatic utricle. The extent of angulation most often membrane, 2.5 cm posteroinferior to the pubic symphysis. The wall of
approximates 30–35° but can change with age and differs between the membranous urethra consists of a muscle coat that is separated from
individuals. The verumontanum is used as a surgical landmark for the the epithelial lining by a narrow layer of fibroelastic connective tissue.
urethral sphincter during transurethral resection for benign enlarge- The muscle coat contains a relatively thin layer of bundles of smooth
ment of the prostate. muscle, which are continuous proximally with those of the prostatic
The two small openings of the ejaculatory ducts open on both sides urethra, and a prominent outer layer of circularly orientated striated
of, or just within, the prostatic utricle, a cul-de-sac approximately 6 mm muscle fibres, which together form the external urethral sphincter.
long, that runs upwards and backwards in the substance of the prostate Urinary continence at the level of the membranous urethra is medi-
behind its median lobe. Its walls are composed of fibrous tissue, muscular ated by the radial folds of urethral mucosa, the submucosal connective
fibres and mucous membrane, the latter pitted by the openings of numer- tissue, the intrinsic urethral smooth muscle, the striated muscle fibres
ous small glands. It develops from the paramesonephric ducts or urogeni- and the pubourethral component of levator ani. The muscle coat of the
tal sinus, and has been thought to be homologous with the vagina of the urethra and puborectalis surround the membranous urethra and are
female so that it is sometimes called the ‘vagina masculina’; the more attached to the inner surface of the ischiopubic ramus; fibres also reach
usual view is that it is a uterine homologue – hence the name ‘utricle’. up to the lowest part of the neck of the bladder and lie on the surface
The lowermost part of the prostatic urethra is fixed by the pubopros- of the prostate. The striated external urethral sphincter has a posterior
tatic ligaments and is therefore immobile. fibrous defect and is inserted throughout its length into the perineal | 1,743 | 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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Cystic dilation of the prostatic utricle (Fig. 75.14) may present in
childhood with urinary tract infections, recurrent epididymitis or
haematuria.
Fig. 75.14 Cystic dilation of the prostatic utricle (arrow) demonstrated in
an 8-month-old child during a micturating cystourethrogram. (Courtesy of
Mr Alok Godse.) | 1,744 | 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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Urethral sinuses Fig. 75.13 The prostatic part of the male urethra.
Internal urethral sphincter The raised part of the urethral crest is
(smooth muscle) the seminal colliculus, known clinically as the
Urethral crest verumontanum. (With permission from Drake RL,
Vogl AW, Mitchell A (eds), Gray’s Anatomy for
Prostate Students, 2nd ed, Elsevier, Churchill Livingstone.
Seminal colliculus Copyright 2010.)
(verumontanum)
Prostatic utricle
Glandular elements
of prostate
Openings of ducts of
glandular elements
of prostate Fibromuscular stroma
(smooth muscle and
Openings of fibrous connective tissue)
ejaculatory ducts
External urethral sphincter
(skeletal muscle)
Deep perineal pouch
Perineal membrane
body. It is related to the dorsal vein complex anteriorly, levator ani later- through the corpus spongiosum is so plentiful that the urethra can be
ally, and the perineal body and rectourethralis posteriorly; it is sus- divided without compromising its vascular supply.
pended from the pubis by fibrous tissue that extends from its anterior
and lateral parts to the puboprostatic ligaments posteriorly and to the Veins
suspensory ligament of the penis anteriorly. The bulbourethral glands The venous drainage of the anterior urethra is to the dorsal veins of the
are invested in sphincteric muscle and drain into the membranous penis and internal pudendal veins, which drain to the prostatic plexus.
urethra during sexual excitement. The posterior urethra drains into the prostatic and vesical venous plex-
uses, which drain into the internal iliac veins.
Anterior part
The anterior, or spongiose, part of the urethra lies within the corpus Lymphatic drainage
spongiosum penis (see Fig. 76.3). In the flaccid penis, it is about 15 cm Vessels from the posterior urethra pass mainly to the internal iliac nodes;
long and extends from the end of the membranous urethra to the a few may end in the external iliac nodes. Vessels from the membranous
external urethral orifice on the glans penis. It starts below the perineal urethra accompany the internal pudendal artery. Vessels from the ante-
membrane at a point anterior to the lowest level of the pubic symphysis rior urethra accompany those of the glans penis, most ending in the
as the bulbar urethra, the widest part of the urethra, surrounded by deep inguinal nodes; some may end in superficial nodes, while others
bulbospongiosus. The bulbourethral glands open into the bulbar may traverse the inguinal canal to end in the external iliac nodes.
urethra approximately 2.5 cm below the perineal membrane. The
urethra next curves downwards as the penile urethra. It is a narrow,
transverse slit when empty, and has a diameter of approximately 6 mm INNERVATION
when passing urine. It is dilated at its termination within the glans
penis, where it is known as the navicular fossa. The external urethral
The prostatic plexus supplies the smooth muscle of the prostate and
orifice is the narrowest part of the urethra and, in the adult, is a sagittal
prostatic urethra (see Fig. 75.11). On each side, it is derived from the
slit, about 6 mm long, bounded on each side by a small labium.
pelvic plexus and lies on the posterolateral aspect of the seminal vesicle
The urethral epithelium, particularly in the bulbar and distal penile
and prostate. The cavernous (deep, cavernosal) nerves, both major and
segments, presents the orifices of numerous small mucous urethral
minor, pierce the bulb of the corpus spongiosum to innervate the cav-
glands that lie in the submucosa. It also contains a number of small
ernous bodies of the penis. The sympathetic autonomic nerves that
pit-like recesses, or lacunae, of varying sizes with orifices directed for-
supply the internal urethral sphincter are derived from the pelvic plexus
wards. One, the lacuna magna, is larger than the rest and is situated in
as it descends in the pelvis adjacent to the inferior prostatovesical
the roof of the navicular fossa.
pedicle and prostate, and function to prevent retrograde ejaculation.
Traumatic injury to the male urethra Parasympathetic preganglionic axons arise from neuronal cell bodies in
the second to fourth sacral spinal segments. The nerve supply of the
external urethral sphincter is controversial. It is generally believed to be
Available with the Gray’s Anatomy e-book
supplied by neurones in Onuf’s nucleus and by perineal branches of
Congenital anomalies of the male urethra the pudendal nerve lying on the perineal aspect of the pelvic floor; in
both instances, the axons arise from neurones in the second to fourth
sacral spinal segments. Fibres from Onuf’s nucleus (somatic) travel with
Available with the Gray’s Anatomy e-book
the pelvic plexus on each side until they branch off to run on the pelvic
aspect of the pelvic floor to enter the membranous urethra.
VASCULAR SUPPLY AND LYMPHATIC DRAINAGE
MICROSTRUCTURE
Urethral artery
The urethral artery arises from the internal pudendal artery or common The epithelium lining the preprostatic urethra and the proximal part
penile artery just below the perineal membrane, and travels through the of the prostatic urethra is a typical urothelium (Fig. 75.15). It is con-
corpus spongiosum to reach the glans penis. It supplies the urethra and tinuous with that lining the bladder, and with the epithelium lining the
the erectile tissue around it. The urethra is also supplied by the dorsal ducts of the prostate and bulbourethral glands, the seminal vesicles,
penile artery, via its circumflex branches on each side and in a retrograde and the vasa deferentia and ejaculatory ducts. These relationships are
fashion from the glans, by its terminal branches. The blood supply important in the spread of urinary tract infections. | 1,745 | 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 mean length of the slit is 5.4 mm in boys between the ages of
0.3 and 15 years (Hutton and Babu 2007). The width of the external
urethral orifice in uncircumcised boys between the ages of 5 months
and 16 years varies from 3.5 to 7.5 mm (Orkiszewski and Madej 2010).
The urethra may be ruptured by a fall-astride (straddle) injury to the
bulbar urethra in the perineum, or by an injury related to a pelvic
fracture. These injuries usually affect the junction of the membranous
with the bulbar segments across the perineal membrane. One of the
complications associated with such injuries is extravasation of urine.
After an injury to the bulbar urethra, urine usually extravasates between
the perineal membrane and the membranous layer of the superficial
fascia (clinically, known as Colles’ fascia). As both of these are attached
firmly to the ischiopubic rami, extravasated fluid cannot pass posteri-
orly because the two layers are continuous around the superficial trans-
verse perineal muscles. Laterally, the spread of urine is blocked by the
pubic and ischial rami. Urine cannot enter the lesser pelvis through the
perineal membrane if this remains intact, and so it tracks anteriorly into
the loose connective tissue of the scrotum and penis, and, from there,
to the anterior abdominal wall. If the posterior urethra is injured, urine
is extravasated into the pelvic extraperitoneal tissue; if the perineal
membrane is also torn, then urine may be extravasated into the
perineum.
Hypospadias, found in 1 in 300 boys, most often results in the urethra
opening in the distal penis, either on the ventral aspect of the penis or,
more proximally, on to the perineum. There is also an associated abnor-
mality of the prepuce, which is longer dorsally and lacking ventrally,
and often an associated chordee, which causes a ventral curvature of
the penis. The microvessel density of the prepuce is reduced in children
with hypospadias and this has surgical implications when preputial
flaps are used for the repair of hypospadias (Yucel et al 2004, Cagri
Savas et al 2011). Anomalies of arterial vascular anatomy of the prepuce
have been described in boys with hypospadias; it is, therefore, impor-
tant for hypospadias to be identified prior to circumcision because the
abnormal foreskin is sometimes used for surgical correction of the
deformity. The anogenital distance (distance from the anus to the base
of penis) is reduced in Caucasian boys with hypospadias (Hsieh et al
2012).
Epispadias occurs in approximately 1 in 100,000 boys; it is typically
part of the exstrophy–epispadias complex but may occur in isolation.
The urethra is either completely open dorsally or uncovered to the level
of the pubic symphysis. The neurovascular bundles are anterolateral
along the proximal portions, and lateral along the middle and distal
portions, of the corporeal bodies (Hurwitz et al 1986). Other features
of epispadias are shortened penis and dorsal chordee; the incidence of
cryptorchidism is increased ten-fold.
Posterior urethral valves occur in 1 in 5000–8000 males and are the
most common cause of urinary outflow obstruction in male infants.
The most common type (type I) is believed to occur if the Wolffian
ducts open too anteriorly on to the primitive prostatic urethra; this
abnormal migration of the ducts leaves behind thick vestigial tissue that
forms rigid valve cusps extending caudally from the verumontanum.
Megalourethra may be associated with posterior urethral valves. Con-
genital anterior urethral valves are a rare cause of urethral obstruction
in boys and may be associated with posterior urethral valves and
hypospadias.
Very rarely, urethral duplication occurs; the two urethrae almost
invariably lie on top of each other rather than side by side. One of the
urethrae, usually the more dorsal, may be blind-ending. Congenital
prepubic sinus consists of a midline tract in the skin passing from the
suprapubic region towards the anterior bladder without communica-
tion, and is believed to be a variant of dorsal urethral duplication.
Congenital urethrocutaneous fistulae are very rare anomalies in which
the urethra opens on the ventral surface of the penis in the absence of
chordee or hypospadias.
Congenital rectourethral fistulae may be present in children born
with anorectal malformation. The prostatic or bulbar urethra is usually
affected, and the rectum and urethra share a common wall immediately
above the fistula site. | 1,746 | 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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Veins
U
The venous plexus around the urethra drains into the vesical venous
plexus around the bladder neck and into the internal pudendal veins
(see Fig. 77.3). An erectile plexus of veins along the length of the urethra
is continuous with the erectile tissue of the vestibular bulb.
LP Lymphatic drainage
The urethral lymphatics drain into the internal and external iliac
nodes.
INNERVATION
Parasympathetic preganglionic axons arise from neuronal cell bodies in
the intermediolateral column of the second to fourth segments of the
sacral spinal cord, run in the pelvic splanchnic nerves, and synapse in
the vesical plexus in or near the bladder wall (see Fig. 77.5B). Postgan-
glionic fibres are distributed to the smooth muscle of the urethral wall.
Somatic fibres to the striated muscle are also derived from the second
Fig. 75.15 The bladder is lined by urothelium with a surface ‘umbrella
to fourth segments of the sacral spinal cord, and run in the pelvic
cell’ layer (U) and a layer of intermediate cells (3–5 cells thick). The
splanchnic nerves but do not synapse in the vesical plexus. Sensory
lamina propria (LP) consists of stroma with blood vessels and von
fibres run in the pelvic splanchnic nerves to the second to fourth seg-
Brunn’s nests.
ments of the sacral spinal cord. Postganglionic sympathetic fibres arise
from the plexus around the vaginal arteries.
The epithelium changes below the openings of the ejaculatory ducts
to a pseudostratified or stratified columnar type, which lines the mem-
MICROSTRUCTURE
branous urethra and the major part of the penile urethra. Mucus-
secreting cells are common throughout this epithelium and frequently
The mucosa lining the female urethra consists of a stratified epithelium
occur in small clusters in the penile urethra. Branching tubular para-
and a supporting lamina propria of loose fibroelastic connective tissue.
urethral glands secrete protective mucus on to the urethral epithelial
The latter is bulky and well vascularized, and contains numerous thin-
lining and are especially numerous on its dorsal aspect. In older men,
walled veins. Its abundant elastic fibres are orientated both longitudi-
many of the deep recesses of the urethral mucosa contain concretions
nally and circularly around the urethra. The lamina propria contains a
similar to those found within prostatic glands (see Fig. 75.23A). Towards
fine nerve plexus, believed to be derived from sensory branches of the
the distal end of the penile urethra, the epithelium changes once again,
pudendal nerves. The proximal part of the urethra is lined by urothe-
becoming stratified squamous in type with well-defined connective
lium, identical in appearance to that of the bladder neck. Distally, the
tissue papillae. This epithelium also lines the navicular fossa and
epithelium changes into a non-keratinizing stratified squamous type
becomes keratinized at the external meatus. The epithelial cells lining
that lines the major portion of the female urethra. This epithelium is
the navicular fossa are glycogen-rich. This may provide a substrate for
keratinized at the external urethral meatus, where it becomes continu-
commensal lactobacilli, which, as in the female vagina, provide a
ous with the skin of the vestibule.
defence against pathogenic organisms.
The wall of the female urethra consists of an outer muscle coat and
an inner mucosa, which lines the lumen and is continuous with that
of the bladder. The muscle coat consists of an outer sheath of striated
FEMALE URETHRA
muscle, together with an inner coat of smooth muscle fibres. The female
external urethral sphincter is anatomically separate from the adjacent
The adult female urethra is approximately 4 cm long and 6 mm in periurethral striated muscle of the anterior pelvic floor. The muscle cells
diameter. The average length of the urethra is 26 mm in girls, increas- forming the external urethral sphincter are all small-diameter, slow-
ing from 23 mm at birth to 32 mm at 15 years (Hirdes et al 2010). It twitch fibres.
begins at the internal urethral orifice of the bladder, approximately The smooth muscle coat extends throughout the length of the
opposite the middle of the pubic symphysis, and runs anteroinferiorly urethra and consists of slender muscle bundles, the majority of which
behind the pubic symphysis, embedded in the anterior wall of the are orientated obliquely or longitudinally. A few circularly arranged
vagina (see Fig. 75.1). It is suspended beneath the pubis by the pos- muscle fibres occur in the outer aspect of the non-striated muscle layer
terior pubourethral ligaments, and anteriorly, by the suspensory liga- and intermingle with the skeletal muscle fibres forming the inner part
ment of the clitoris. It crosses the perineal membrane and normally of the external urethral sphincter. Proximally, the urethral smooth
ends at the external urethral orifice in the vestibule as an anteropos- muscle extends as far as the bladder neck, where it is replaced by fasci-
terior slit with rather prominent margins, directly anterior to the cles of detrusor smooth muscle. This region in the female lacks a well-
opening of the vagina and 2.5 cm behind the glans clitoris. It some- defined circular smooth muscle component comparable with the
times opens into the anterior vaginal wall. Except during the passage preprostatic sphincter of the male. Distally, urethral smooth muscle
of urine, the anterior and posterior walls of the urethra are in apposi- bundles terminate in the subcutaneous adipose tissue surrounding the
tion and the epithelium is thrown into longitudinal folds, one of external urethral meatus.
which, on the posterior wall of the canal, is termed the urethral crest. The smooth muscle of the female urethra receives an extensive pre-
Many small, mucous urethral glands and minute, pit-like recesses or sumptive cholinergic parasympathetic nerve supply but contains rela-
lacunae open into the urethra and may give rise to urethral diverticula. tively few noradrenergic nerves. In the absence of an anatomical bladder
On each side, near the lower end of the urethra, a number of these neck sphincter, competence of the female bladder neck and proximal
glands, Skene’s glands, are grouped together and open into the para- urethra is unlikely to be totally dependent on smooth muscle activity,
urethral duct; each duct runs down in the submucous tissue and ends and is more probably related to the support provided by the ligamen-
in a small aperture on the lateral margin of the external urethral tous structures that surround them. The innervation and longitudinal
orifice. orientation of most of the muscle fibres suggest that urethral smooth
Epispadias is a rare congenital anomaly that may affect the female muscle in the female is active during micturition, serving to shorten
urethra. It may occur in isolation or as part of the exstrophy–epispadias and widen the urethral lumen.
complex. Isolated epispadias in girls is characterized by the urethra
opening at the clitoris, which is typically bifid.
MICTURITION AND URINARY CONTINENCE
VASCULAR SUPPLY AND LYMPHATIC DRAINAGE
The central integration of nervous control of the bladder and urethra is
essential for normal micturition (Fig. 75.16). (For further reading, see
Urethral artery
Yoshimura and Chancellor (2012).)
The urethra is supplied principally by the vaginal artery, but also receives Micturition consists of storage and voiding phases. During the
a supply from the inferior vesical artery. storage phase, the bladder accommodates an increasing volume of urine | 1,747 | 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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Lateral aspect Medial aspect Fig. 75.16 The micturition control centre is in
the paramedian pontine reticular formation on
Anterior cingulate cortex (ACCx)
each side and consists of a medially placed
micturition centre, ‘M’, and a laterally placed
5 Paracentral lobule
storage centre, ‘L’. Neurones project from the
‘M’ centre and the storage centre ‘L’ to
parasympathetic neurones in segments 2–4 of
the sacral spinal cord, and to Onuf’s nucleus,
which is in the same segments, and which
innervates the external urethral sphincter. At
higher levels, neurones in the right prefrontal
and anterior cingulate cortex, right preoptic
Ventral posterior
4 nucleus of thalamus nucleus and periaqueductal grey matter are
involved in the control of micturition. Vesical
afferents from stretch receptors in the detrusor
Periaqueductal grey
and trigonal mucosa relay the extent of
matter (PAG)
bladder filling to the brainstem and thalamus
via spinoreticulothalamic fibres (1). Activity in
Inferior frontal gyrus
the sympathetic system that maintains
Preoptic area
increases in bladder compliance (via β2
receptors on detrusor fibres) and
parasympathetic activity is inhibited (2).
Pons Spinoreticular fibres synapsing in the ‘L’
nucleus in the pons activate Onuf’s nucleus to
'L' centre 'M' centre increase the tone of the external sphincter (3).
If micturition is deferred, fibres projecting from
the inferior frontal gyrus inhibit the right
anterior cingulate gyrus, preoptic area and
periaqueductal grey matter (4). Voluntary
contraction of the pelvic floor musculature,
controlled by the prefrontal cortex driving the
perineal ‘area’ of the motor cortex (5), cannot
be long sustained once filling is complete.
(With permission from FitzGerald MJT,
3
Preganglionic sympathetic supply Folan-Curren J 2001 Clinical Neuroanatomy,
Spinoreticulothalamic fibre to pelvic ganglia 4th edn. London: Saunders.)
Internuncial neurone
S2/S3 posterior nerve
Sacral parasympathetic neurone
root in cauda equina
Motor neurone to levator ani
Onuf 's nucleus
1 1
Mucosal afferent fibre 2
To levator ani
To external urethral sphincter To pelvic ganglia
without any change in intravesical pressure, partly because of the vis- urinary continence in the male
coelastic properties of its walls, and partly because a gating mechanism Urinary continence at the level of the membranous urethra is mediated
operates in the spinal cord that reflexively inhibits preganglionic para- by the radial folds of urethral mucosa, the submucosal connective
sympathetic activity. A gating mechanism in the pelvic ganglia prevents tissue, the intrinsic urethral smooth muscle, the striated external ure-
the activation of postganglionic parasympathetic neurones until pre- thral sphincter and the pubourethral component of levator ani, pubo-
ganglionic activity has reached a threshold level (Chancellor and perinealis (Fig. 75.17). The external urethral sphincter represents the
Yoshimura 2002). point of highest intraurethral pressure in the normal, contracted, state.
Mean bladder capacity in adult males varies around 400 ml but The striated muscle component of the external urethral sphincter is
micturition commonly occurs at smaller volumes. Voluntary control is devoid of muscle spindles. The striated muscle fibres themselves are
imposed from the inferior frontal gyrus of the cerebral cortex. Filling unusually small in cross-section (15–20 µm in diameter), and are phys-
to 500 ml may be tolerated; beyond this level, pain caused by tension iologically of the slow-twitch type, unlike the pelvic floor musculature,
in the bladder wall leads to the urgent desire to micturate. The pain is which is a heterogeneous mixture of slow- and fast-twitch fibres of
referred to the cutaneous areas supplied by T10–L2 and S2–4, includ- larger diameter. The slow-twitch fibres of the external sphincter are
ing the lower anterior abdominal wall, perineum and penis. Threshold capable of sustained contraction over relatively long periods of time
afferent stimulation activates the micturition centre in the rostral pons and actively contribute to the tone that closes the urethra and maintains
(the ‘M’ centre) (see Fig. 75.16), which drives preganglionic parasym- urinary continence. They are innervated by neurones that lie in Onuf’s
pathetic neurones in the intermediolateral grey column of the second, nucleus in the anterolateral grey matter of the second to fourth sacral
third and fourth sacral spinal segments via descending spinal path- spinal segments. Their firing is controlled centrally by a storage centre
ways. The axons of these neurones run to the inferior hypogastric within the rostral pons (the ‘L’ centre) (see Fig. 75.16). Just before the
plexus in the pelvic splanchnic nerves; they synapse on postganglionic onset of voiding, the external urethral sphincter is relaxed by central
neurones in ganglia lying within the plexus and in the wall of the inhibition of Onuf’s nucleus.
bladder. Postganglionic axons ramify throughout the thickness of the
detrusor smooth muscle coat. When stimulated, they release acetylcho- urinary continence in the female
line, which activates muscarinic receptors in the detrusor layer of the The urethral sphincter mechanism consists of the intrinsic striated and
bladder wall and produces the sustained bladder contraction required smooth muscle of the urethra, the mucosa and submucosal connective
for micturition. The distal urethral sphincter maintains urethral tissue, and the puborectalis component of levator ani (which surrounds
closure. the urethra at the point of maximum concentration of those muscles). | 1,748 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Bladder, prostate and urethra
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Bladder
Prostate
Striated sphincter &
membranous urethra
Levator ani (puboperinealis)
Bulbourethral glands
Anterior recess of ischioanal fossa
Perineal membrane
Ischiopubic ramus
Corpus spongiosum (bulb)
Corpus cavernosum
Ischiocavernosus
A B
Fig. 75.17 A, Coronal illustration of male anterior levator ani (urogenital) hiatus: prostate above, intervening striated urethral sphincter and perineal
membrane with corporal bodies below. B, This coronal T2-weighted MRI includes the cephalad extension of the smooth muscle urethral sphincter, which
cannot be discriminated from striated urethral sphincter; bulbourethral glands are offset from expected symmetry. (A, B Courtesy of Robert P Myers MD,
Akira Kawashima MD and Bernard F King MD, used with permission of Mayo Foundation for Medical Education and Research.)
The striated muscle component of the urethral sphincter mechanism about 8 g in youth but, almost invariably, enlarges with the develop-
surrounds the middle and lower thirds of the urethra in the female. ment of BPH; it usually weighs 40 g, but sometimes as much as 150 g
Proximally, it forms a complete ring around the urethra, while, more or even more, after the first five decades of life. The small prostate
distally, it covers the anterior and lateral aspects of the urethra; it blends without BPH is described as a croissant shape (short anterior commis-
above with the smooth muscle of the bladder neck and below with the sure, prominent apical notch and posterior lip of prostatic tissue), and
smooth muscle of the lower urethra and vagina. Contraction of this part the enlarged gland is more doughnut-shaped. The shape of the prostate
of the sphincter compresses the urethra against the relatively fixed affects the relationship of the prostatic apex to the external urethral
anterior vaginal wall. At its most distal point; the striated sphincter sphincter. This relationship is important when removing the prostate
encompasses the urethra and vagina as the urethrovaginal sphincter. at radical prostatectomy for cancer, and anastomosing the bladder to
The mucosa and submucosa are oestrogen-dependent and atrophy the urethra to maintain sphincter integrity. The external urethral sphinc-
postmenopausally, possibly resulting in stress incontinence. ter is flush to a large doughnut-type gland, and so a perpendicular
incision will separate the prostate and external urethral sphincter accu-
rately. In a small prostate, the external urethral sphincter fills the defect
PROSTATE
in the anterior aspect of the prostate, and so a perpendicular incision
at the level of the posterior lip of the croissant-shaped gland will excise
The prostate is a globular fibromuscular gland that surrounds the pro- much external urethral sphincter and leave the patient incontinent.
static urethra from the bladder base to the membranous urethra (Myers Superiorly, the base is largely contiguous with the neck of the
2001). It is enclosed by firmly adherent tissue that has been variously bladder. The apex is inferior, surrounding the junction of the prostatic
termed the prostatic capsule or the prostatic fascia (parietal fascia cover- and membranous parts of the posterior urethra. The apical posterior
ing the adjacent part of levator ani, lateral pelvic fascia, periprostatic relation of the prostate and external urethral sphincter is rectourethralis,
fascia, parapelvic fascia), reflecting, in part at least, inter-individual a Y-shaped muscle that originates from the outer longitudinal coat of
variability and sampling site (Myers et al 2010) (Fig. 75.18). Histologi- the rectum. The upper limbs of the Y extend from the lateral rectal wall
cally, it is a multilayered connective tissue (Hinata et al 2013). There is to the midline, where rectourethralis inserts into the perineal body at
no true fibrous capsule at the base or apex of the prostate, and the pres- the anorectal junction (Brooks et al 2002).
ence of a capsule between the apex and base is variable. The anterior surface lies in the arch of the pubis, separated from it
The muscular tissue within the prostate is mainly smooth muscle. by the dorsal vascular complex (Santorini’s plexus) and loosely attached
Anterior to the urethra, a layer of smooth muscle merges with the main adipose tissue. It is transversely narrow and convex, extending from the
mass of muscle in the fibromuscular septa; it blends superiorly with apex to the base. Near its superior limit, it is connected to the pubic
vesical smooth muscle. Anterior to the layer of smooth muscle, a trans- bones by the puboprostatic ligaments. The urethra emerges from this
versely crescent-shaped mass of skeletal muscle is continuous inferiorly surface anterosuperior to the apex of the gland. The anterior part of the
with the external urethral sphincter in the deep perineal pouch. Its fibres prostate is relatively deficient in glandular tissue and is largely com-
pass transversely internal to the capsule and are attached to it laterally posed of fibromuscular tissue. The anterior and lateral aspects of the
by diffuse collagen bundles; other collagen bundles pass posteromedi- prostate are covered by a layer of fascia derived from the endopelvic
ally, merging with the prostatic fibromuscular septa and the septum of fascia on each side, called the lateral prostatic fascia. This is adherent
the urethral crest. This muscle, supplied by the pudendal nerve, probably medially to the prostate, continues posteriorly over the lateral aspect of
compresses the urethra but it may pull the urethral crest back and the the prostate, neurovascular bundles and rectum (lateral rectal fascia),
prostatic sinuses forwards, dilating the urethra. Glandular contents may and passes distally over the urethra (see Fig. 75.18A). The prostatic
be expelled simultaneously into the urethra when it has expanded in venous plexus (see Fig. 75.19) lies between this extension of the
this way, so that it contains 3–5 ml seminal fluid prior to ejaculation. endopelvic fascia and the prostate. Anteroinferiorly, the parietal and
The prostate lies at a low level in the lesser pelvis, behind the inferior visceral fasciae of the prostate merge and blend with the puboprostatic
border of the pubic symphysis and pubic arch (see Fig. 75.2A; Fig. ligaments. The anterior surface of the prostate and associated vascular
75.19), and anterior to rectourethralis and the rectal ampulla, through plexus is covered by the detrusor apron (Myers 2002).
which it may be palpated. It presents a base or vesical aspect superiorly, The inferolateral surfaces are related to the muscles of the pelvic side
an apex inferiorly, and posterior, anterior and two inferolateral surfaces. wall; the anterior fibres of levator ani embrace the prostate in the pubo-
The prostatic base measures about 4 cm transversely. The gland is 2 cm urethral sling or pubourethralis. These muscles are separated from the
in its anteroposterior, and 3 cm in its vertical, diameters. It weighs prostate by a thin layer of connective tissue. | 1,749 | 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 Parietal endopelvic Superficial The posterior surface of the prostate is transversely flat and vertically
fascia dorsal vein convex. Near its superior (juxtavesical) border is a depression where it
Detrusor apron Dorsal vascular is penetrated by the two ejaculatory ducts. Below this is a shallow,
complex median sulcus, usually considered to mark a partial separation into
right and left lateral lobes. It is separated from prerectal fat in the pre-
rectal space (see Figs 75.2A, 75.18A) and rectum by Denonvilliers’
Prostate
Lateral prostatic fascia, a condensation of pelvic fascia that develops by obliteration of
fascia Levator ani the rectovesical peritoneal pouch, and by loose yellow, fatty areolar
tissue. The rectovesical pouch is obliterated from below upwards as fetal
life progresses, forming Denonvilliers’ fascia; at birth, this fascia sepa-
rates the prostate, the seminal vesicles and the ampullae of the vasa
deferentia from the rectum. The superior limit of Denonvilliers’ fascia
is the peritoneum of the rectovesical pouch. Laterally, Denonvilliers’
fascia fuses with the lateral pelvic fascia; anterior to Denonvilliers’
fascia, the lateral pelvic fascia is called the lateral prostatic fascia and,
posterior to Denonvilliers’ fascia, it is called the lateral rectal fascia.
The prostate is traversed by the urethra and ejaculatory ducts, and
contains the prostatic utricle. The urethra enters the prostate near its
anterior border and usually passes between its anterior and middle
thirds. The ejaculatory ducts pass anteroinferiorly through its posterior
region to open into the prostatic urethra.
ZONAL ANATOMY OF THE PROSTATE
The prostate gland was once thought to be divided into five anatomical
lobes, but it is now recognized that five lobes can only be distinguished
in the fetal gland prior to 20 weeks’ gestation. Between then and the
onset of BPH, only three lobes are recognizable: two lateral and a
median lobe. Clinicians refer to left and right ‘lobes’ when describing
either what can be felt on rectal palpation, or the endoscopically visible
abnormalities that are seen in the diseased state when prostatic anatomy
is distorted by BPH.
From an anatomical, and particularly from a morbid anatomical,
perspective, the glandular tissue may be subdivided into three distinct
zones (Figs 75.20–75.22): peripheral (70% by volume), central (25%
by volume) and transitional (5% by volume) (Mundy et al 1999b).
Non-glandular tissue (fibromuscular stroma) fills the space between the
peripheral zones anterior to the preprostatic urethra. The central zone
surrounds the ejaculatory ducts, posterior to the preprostatic urethra,
and is more or less conical in shape, with its apex at the verumontanum.
The fibromuscular stroma includes the smooth muscle detrusor apron
Lateral rectal Denonvilliers’ Rectal wall Prerectal fat Neurovascular
superoanteriorly and striated urethral sphincter fibres that extend ante-
fascia fascia bundle
riorly over the anterior prostate on to the bladder neck. The transitional
zone lies around the distal part of the preprostatic urethra just proximal
to the apex of the central zone and the ejaculatory ducts; it includes the
smooth muscle of the preprostatic urethral wall. Its ducts enter the
PC prostatic urethra just below the preprostatic sphincter and just above
the ducts of the peripheral zone. The peripheral zone is cup-shaped and
NVB encloses the central transitional zone and the preprostatic urethra,
except anteriorly, where the space is filled by the anterior fibromuscular
stroma. Simple mucus-secreting glands lie in the tissue around the
preprostatic urethra, above the transitional zone and surrounded by the
preprostatic sphincter. These simple glands are similar to those in the
female urethra and unlike the glands of the prostate.
On magnetic resonance imaging (MRI), the prostate gland has a
zonal anatomy on T2-weighted images (see Fig. 75.21). The normal
peripheral zone has high-signal intensity, as does fluid within the
seminal vesicles. The central and transitional zones have relatively low
signal and are often referred to as the ‘central gland’. The verumonta-
num may be seen as high-signal within the central gland. The relation-
ship of the zones of the gland normally changes with age. The central
B
zone atrophies, and the transitional zone enlarges secondary to BPH.
This often produces a low-signal band at the margin of the hypertro-
Fig. 75.18 A, The endopelvic fascia. The fascia covers the pelvic viscera
phied transitional and compressed peripheral zones: the surgical pseu-
and continues posteriorly over the lateral aspect of the prostate, as the
docapsule, which is well seen on T2-weighted MR images.
lateral prostatic fascia and, on the lateral aspect of the rectum, as the
lateral rectal fascia. Its relationship with Denonvilliers’ fascia may be The zonal anatomy of the prostate is clinically important because
visualized as an ‘H’. The deep dorsal vein and lateral branches run deep most carcinomas arise in the peripheral zone, whereas BPH affects the
to the endopelvic fascia and the lateral prostatic fascia, although transitional zone, which may grow to form the bulk of the prostate.
communicating with perforators to the pelvic side wall. Denonvilliers’
fascia is adherent to the prostate in the posterior midline but, like the
VASCULAR SUPPLY AND LYMPHATIC DRAINAGE
lateral prostatic fascia, is separated from the prostatic tissue by the
neurovascular structures and fatty tissues elsewhere. Between
Denonvilliers’ fascia and the rectum is a fatty potential plane, the prerectal Arteries
space. B, The prostatic capsule (PC) is a condensation of connective
tissue (green) on the surface of the gland and encloses the neurovascular The prostate is supplied by branches from the inferior vesical, internal
bundle (NVB). The prostatic fibromuscular stroma and glands lie beneath
pudendal and middle rectal arteries (see Fig. 75.19). They perforate the
the capsule.
gland along a posterolateral line from the junction of the prostate with
the bladder down to the apex of the gland. | 1,750 | 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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As the transitional zone grows, it produces the appearance of ‘lobes’
on either side of the urethra. In due course, these lobes may compress
or distort the preprostatic and prostatic parts of the urethra and produce
symptoms. The central zone surrounding the ejaculatory ducts is rarely
involved in any disease. It shows certain histochemical characteristics
that differentiate it from the rest of the prostate; it is thought to be
derived from the Wolffian duct system (much like the epididymi, vasa
deferentia and seminal vesicles), whereas the rest of the prostate is
derived from the urogenital sinus (p. 1218). | 1,751 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Bladder, prostate and urethra
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Hypogastric nerve (Sympathetic) S2–S4 (Parasympathetic)
Colon
Ureter
Vas deferens
Peritoneum
Inferior vesical artery and
vein
Pelvic plexus
Seminal vesicle
Bladder/detrusor Levator ani
Pubic bone Arterial blood
Superficial branch supply to bladder neck
of dorsal vein
Rectum
Puboprostatic ligaments
Capsular artery and vein
Vas deferens of the prostate
Cremaster
Dartos External anal sphincter
Crus penis Deep transverse perineal muscle
Cavernous artery
Bulbospongiosus
Ischiocavernosus
Prostate Bulbourethral gland
Urethral sphincter Cavernous nerve
Fig. 75.19 A sagittal section of the male pelvis. The pelvic plexus lies with its midpoint level with the tip of the seminal vesicles. It gives branches to the
prostate, bladder urethra, seminal vesicles, rectum and corpora cavernosa via the cavernous nerves. The cavernous nerves are the continuation of the
neurovascular bundles, lying posterolateral to the prostate. These bundles may be damaged at radical prostatectomy, resulting in impotence.
The inferior vesical artery often arises from the internal iliac artery Commentary 8.1). The prostatic capsule is covered by numerous nerve
with the middle rectal artery. It gives rise to two groups of branches: the fibres and ganglia posterolaterally, forming a crescentic periprostatic
urethral and capsular. The urethral vessels enter at the prostatovesical nerve plexus. The greatest density of nerves is found in the preprostatic
junction, principally posteriorly at the 5 and 7 o’clock positions, but sphincter; fewer fibres are found in the anterior fibromuscular stroma,
also anteriorly at 1 and 11 o’clock. This bladder neck arterial anatomy and the peripheral zone is the least densely innervated. Nerves contain-
is always apparent at transurethral resection of the prostate and open ing neuropeptide Y and vasointestinal polypeptide (VIP) are localized
removal of BPH adenomas. The capsular arteries run posterolaterally in the subepithelial connective tissue, in the smooth muscle layers of
and inferiorly in the neurovascular bundles, providing perpendicular the gland, and in the walls of its blood vessels. Neurovascular bundles
perforating vessels to the prostate. The most constant in position and (Walsh and Donker 1982) containing autonomic nerves that supply the
prominence is the apical perforator at the prostatourethral junction, an prostate, seminal vesicles, prostatic urethra, ejaculatory ducts, corpora
important landmark for this point and for the neurovascular bundle at cavernosa, corpus spongiosum, membranous and penile urethra, and
radical prostatectomy. bulbourethral glands are closely applied to, but separable from, the
posterolateral margins of the prostate (see Commentary 8.1). They are
Veins intimately related to the prostatic fascia. These nerves may be damaged
during radical prostate surgery for organ-confined prostate cancer, pro-
ducing impotence, or sacrificed as part of wide local excision of the
The veins run into a plexus around the anterolateral aspects of the
prostate (Tewari et al 2006, Pisipati et al 2014).
prostate, posterior to the arcuate pubic ligament and the lower part of
The somatic pudendal nerve supplies the external urethral sphincter.
pubic symphysis, anterior to the bladder and prostate. The chief tribu-
The branches enter at the 5 and 7 o’clock positions. Sensory branches
tary is the deep dorsal vein of the penis. The plexus also receives anterior
pass through the penile hilus in association with the dorsal venous
vesical and prostatic rami (which connect with the vesical plexus and
complex and dorsal vein of the penis.
internal pudendal vein), and drains into vesical and internal iliac veins.
Lymphatic drainage
MICROSTRUCTURE
Collecting vessels from the vas deferens drain into the external iliac
nodes, while those from the seminal vesicle drain to the internal and The glandular tissue consists of numerous follicles with frequent inter-
external iliac nodes. Prostatic vessels end mainly in internal iliac, sacral nal papillae. Follicles open into elongated canals, which join to form
and obturator nodes. A vessel from the posterior surface accompanies 12–20 main ducts. The follicles are separated by loose connective tissue,
the vesical vessels to the external iliac nodes, and another from the supported by extensions of the fibrous capsule and muscular stroma,
anterior surface reaches the internal iliac group by joining vessels that and enclosed in a delicate capillary plexus. Follicular epithelium is
drain the membranous urethra. variable but predominantly columnar, and either single-layered or
pseudostratified.
Prostatic ducts open mainly into the prostatic sinuses in the
INNERVATION floor of the prostatic urethra. They have a bilayered epithelium, the
luminal layer is columnar, and the basal layer is populated by small
The prostate receives an abundant nerve supply from the inferior cuboidal cells. Small colloid amyloid bodies (corpora amylacea) are
hypogastric (pelvic) plexus (see Figs 59.4, 75.11 and Fig. 8.1.1 in frequent in the follicles (Fig. 75.23). Prostatic and seminal vesicular | 1,752 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
prostate
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Central and transitional Verumontanum Bladder Peripheral zone of
zones of prostate prostate
TZ TZ
PZ PZ
A
A
TZ
PZ
B
Fig. 75.20 Ultrasound of the prostate. A, An axial view showing the
hypoechoic transition zone (TZ) and the more echogenic peripheral zone
(PZ). Their interface is the surgical capsule (*). B, A sagittal view showing
the hypoechoic transition zone (TZ) and the more echogenic peripheral
zone (PZ).
secretions form the bulk of seminal fluid. Prostatic secretions are
slightly acid, and contain acid phosphatase, amylase, prostate-specific
antigen, fibrinolysin and zinc. Numerous neuroendocrine cells, con- B
taining neurone-specific enolase, chromogranin and serotonin
(5-hydroxtryptamine, 5-HT), are present in the glandular epithelium; Peripheral zone of Prostatic Central and transitional Bladder
their numbers decline after middle age and their function is unknown. prostate urethra zones of prostate
Histological sections just above the level of the verumontanum
Fig. 75.21 Magnetic resonance imaging (MRI) of the prostate. A, A
reveal two concentric, partially circumurethral, zones of glandular
T2-weighted MRI scan showing the normal high signal of the peripheral
tissue. The larger outer zone is the peripheral zone and has long, zone and the intermediate signal of the central and transitional zones and
branched glands, whose ducts open mainly into the prostatic sinuses. the verumontanum in the central gland. B, A T2-weighted coronal MRI
The inner zone is the transitional zone and consists of glands whose scan of the prostate showing the zonal anatomy.
ducts open on the floor of the prostatic sinuses and colliculus seminalis,
and a group of simple mucosal glands that surround the preprostatic
urethra. Anteriorly, in the prostatic isthmus, the peripheral zone and
submucosal glands are absent. the ductal branches. Morphogenesis and differentiation of the epithelial
cords starts in an intermediate part of the epithelial anlage and proceeds
to the urethral and subcapsular parts of the gland; the latter is reached
AGE CHANGES IN THE PROSTATE by the age of 17–18 years. The glandular epithelium is initially multi-
layered squamous or cuboidal, and is transformed into a pseudostrati-
At birth, the prostate has a system of ducts embedded in a stroma that fied epithelium consisting of basal, exocrine secretory (including
forms a large part of the gland. Follicles are represented by small end- mucous) and neuroendocrine cells. The mucous cells are temporary,
buds on the ducts. Before birth, the epithelium of the ducts, seminal and are lost as the gland matures. The remaining exocrine secretory cells
colliculus and prostatic utricle display hyperplasia and squamous meta- produce a number of products, including acid phosphatase, prostate-
plasia, possibly due to maternal oestrogens in the fetal blood. This specific antigen and β-microseminoprotein. Growth of the secretory
subsides after birth and is followed by a period of quiescence lasting component is associated with condensation of the stroma, which
for 12–14 years. diminishes relative to the glandular tissue. These changes are probably
At puberty, between the ages of approximately 14 and 18 years, the a response to the secretion of testosterone by the testis.
prostate gland enters a maturation phase and more than doubles in size During the third decade, the glandular epithelium grows by irregular
during this time. Growth is almost entirely due to follicular develop- multiplication of the epithelial infoldings into the lumen of the folli-
ment, partly from end-buds on ducts, and partly from modification of cles. After the third decade, the size of the prostate remains virtually | 1,753 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Bladder, prostate and urethra
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noItCes
Transition zone
CCAA
CCAA
A
Central zone BB
EE
B
Fig. 75.23 A, Prostatic acini show papillary infoldings at the base of the
gland (central zone). They are irregularly divided by fibromuscular stroma.
Peripheral zone Some acini contain eosinophilic (pink) secretions called corpora amylacea
(CA) (×10, haematoxylin and eosin stain). B, Prostatic acini consist of a
double layer of epithelial cells (E), which line the lumen, and basal cells
(B), which give rise to epithelial cells.
Anterior fibromuscular stroma
Bonus e-book images and videos
Fig. 75.6 Centiles of bladder volume index in children.
Fig. 75.8 A laparoscopic view of the empty bladder and median
and medial umbilical folds in a 12-month-old boy.
Fig. 75.9 A laparoscopic view of the left inferior epigastric vein
(lateral umbilical ligament) in a 12-month-old boy.
Fig. 75.14 Cystic dilation of the prostatic utricle demonstrated in an
Fig. 75.22 The zonal anatomy of the prostate. (With permission from 8-month-old child during a micturating cystourethrogram.
Walsh PC, Retik AB, Vaughan ED et al (eds) 2002 Campbell’s Urology,
8th edition. Philadelphia: Saunders.) Video 75.1 Laparoscopic view of bladder filling and emptying in
relation to the rectovesical pouch.
Video 75.2 Laparoscopic view of anterior abdominal wall and
unaltered until 45–50 years, when the epithelial foldings tend to disap-
ligaments.
pear, follicular outlines become more regular, and amyloid bodies
increase in number: all signs of prostatic involution. After 45–50 years,
the prostate tends to develop BPH: an age-related condition. If a man
lives long enough, then BPH is inevitable, although not always
symptomatic.
Acknowledgements
Robert P Myers, Emeritus Professor of Urology, and Akira Kawashima
and Bernard F King, Professors of Radiology, Mayo Clinic College of
Medicine. | 1,754 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Bladder, prostate and urethra
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BPH begins as micronodules in the transitional zone, which grow
and coalesce to form macronodules around the inferior margin of the
preprostatic urethra, just above the verumontanum. Macronodules, in
turn, compress the surrounding normal tissue of the peripheral zone
posteroinferiorly, creating a ‘false capsule’ around the hyperplastic
tissue, which, coincidentally, provides a plane of cleavage for its surgical
enucleation (for further reading see Kutikov et al (2006)). | 1,755 | 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
KEY REFERENCES
Kutikov A, Guzzo TJ, Malkowicz SB 2006 Clinical approach to the prostate: Walsh PC, Donker PJ 1982 Impotence following radical prostatectomy:
an update. Radiol Clin North Am 44:649–63. insight into etiology and prevention. J Urol 128:492–7.
Details the practical approach to diseases of the prostate. A landmark assessment of the importance of neurovascular anatomy in
prostate surgery.
Myers RP 2001 Practical surgical anatomy for radical prostatectomy. Urol
Clin North Am 28:473–90. Yoshimura N, Chancellor MB 2012 Physiology and pharmacology of the
Details clinically relevant anatomy of the prostate and surrounding bladder and urethra. In: Wein AJ, Kavoussi LR, Novick AC et al (eds)
structures. Campbell-Walsh Urology, 10th ed. Philadelphia: Elsevier, Saunders;
Ch. 60.
Mundy AR, Fitzpatrick J, Neal D et al 1999a Structure and function of the
An overview of physiology and pharmocology of the lower urinary tract.
lower urinary tract. In: The Scientific Basis of Urology. Oxford: Isis
Medical Media; Ch. 11, pp. 217–42.
A detailed assessment of the structure and function of the lower urinary
tract.
Mundy AR, Fitzpatrick J, Neal D et al (eds) 1999b The prostate and benign
prostatic hyperplasia. In: The Scientific Basis of Urology. Oxford: Isis
Medical Media; Ch. 13, pp. 257–76.
An account that includes a review of prostatic zonal anatomy. | 1,756 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Bladder, prostate and urethra
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REFERENCES
Andersson KE, McCloskey KD 2014 Lamina propria: the functional center Myers RP 2001 Practical surgical anatomy for radical prostatectomy. Urol
of the bladder? Neurourol Urodyn 33:9–16. Clin North Am 28:473–90.
Brooks JD, Eggener SE, Chao W-E 2002 Anatomy of the rectourethralis Details clinically relevant anatomy of the prostate and surrounding
muscle. Eur Urol 41:94–100. structures.
Cagri Savas M, Kapucuoglu N, Gursoy K et al 2011 The microvessel density Myers RP 2002 Detrusor apron, associated vascular plexus, and avascular
of the hypospadiac prepuce in children. J Pediatr Urol 7:162–5. plane: relevance to radical retropubic prostatectomy – anatomic and
Chancellor MB, Yoshimura N 2002 Physiology and pharmacology of the surgical commentary. Urology 59:472–9.
bladder and urethra. In: Walsh PC et al (eds) Campbell’s Urology Study An explanation of the neurological components of bladder function from the
Guide, 10th ed. Philadelphia: Elsevier, Saunders; Ch. 23. higher cortical centres to molecular events within the cells of the detrusor
muscle.
Drumm BT, Koh SD, Andersson KE et al 2014 Calcium signalling in Cajal-
like interstitial cells of the lower urinary tract. Nat Rev Urol 11: Myers RP, Cheville JC, Pawlina W 2010 Making anatomic terminology of the
555–64. prostate and contiguous structures clinically useful: historical review
Hinata N, Sejima T, Takenaka A 2013 Progress in pelvic anatomy from the and suggestions for revision in the 21st century. Clin Anat 23:18–29.
viewpoint of radical prostatectomy. Int J Urol 20:260–70. Orkiszewski M, Madej J 2010 The meatal/urethral width in healthy uncir-
Hirdes MM, de Jong TP, Dik P et al 2010 Urethral length in girls with lower cumcised boys. J Pediatr Urol 6:130–3.
urinary tract symptoms and forme fruste of female epispadias. J Pediatr Pisipati S, Ali A, Mandalapu RS et al 2014 Newer concepts in neural anatomy
Urol 6:372–5. and neurovascular preservation in robotic radical prostatectomy. Indian
Hsieh MH, Eisenberg ML, Hittelman AB et al 2012 Caucasian male infants J Urol 30:399–409.
and boys with hypospadias exhibit reduced anogenital distance. Hum Stalberg K, Gonzalez R 2012 Urethral atresia and anhydramnios at 18 weeks
Reprod 27:1577–80. of gestation can result in normal development. J Pediatr Urol 8:
Hurwitz RS, Woodhouse CR, Ransley P 1986 The anatomical course of the e33–5.
neurovascular bundles in epispadias. J Urol 136:68–70. Takahashi T, Ueno M, Azekura K et al 2000 Lateral ligament: its anatomy
Hutton KA, Babu R 2007 Normal anatomy of the external urethral meatus and clinical importance. Semin Surg Oncol 19:386–95.
in boys: implications for hypospadias repair. BJU Int 100:161–3. Tewari A, Takenaka A, Mtui E et al 2006 The proximal neurovascular plate
Klutke CG, Siegel CL 1995 Functional female pelvic anatomy. Urol Clin and the trizonal neural architecture around the prostate gland: impor-
North Am 22:487–98. tance in the athermal robotic technique of nerve sparing prostatectomy.
BJU Int 98:314–23.
Kutikov A, Guzzo TJ, Malkowicz SB 2006 Clinical approach to the prostate:
an update. Radiol Clin North Am 44:649–63. Walsh PC, Donker PJ 1982 Impotence following radical prostatectomy:
Details the practical approach to diseases of the prostate. insight into etiology and prevention. J Urol 128:492–7.
A landmark assessment of the importance of neurovascular anatomy in
Miles WE 1908 A method of performing abdominoperineal excision for prostate surgery.
carcinoma of the rectum and of the terminal portion of the pelvic colon.
Lancet 2:1812–14. Yoshimura N, Chancellor MB 2012 Physiology and pharmacology of the
bladder and urethra. In: Wein AJ, Kavoussi LR, Novick AC et al (eds)
Mundy AR, Fitzpatrick J, Neal D et al 1999a Structure and function of the
Campbell-Walsh Urology, 10th ed. Philadelphia: Elsevier, Saunders;
lower urinary tract. In: The Scientific Basis of Urology. Oxford: Isis
Ch. 60.
Medical Media; Ch. 11, pp. 217–42.
An overview of physiology and pharmocology of the lower urinary tract.
A detailed assessment of the structure and function of the lower urinary
tract. Yucel S, Guntekin E, Kukul E et al 2004 Comparison of hypospadiac and
normal preputial vascular anatomy. J Urol 172: 1973–6.
Mundy AR, Fitzpatrick J, Neal D et al (eds) 1999b The prostate and benign
prostatic hyperplasia. In: The Scientific Basis of Urology. Oxford: Isis
Medical Media; Ch. 13, pp. 257–76.
An account that includes a review of prostatic zonal anatomy. | 1,757 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
CHAPTER
76
Male reproductive system
mesothelium.Thepotentialspacebetweenthevisceralandparietal
INTRODUCTION
layers–thecavityofthetunicavaginalis–isnormallyoccupiedbya
thinfilmofclear,straw-colouredfluid.Thevolumeofthisfluidcan
Themalereproductivesystemconsistsofthegonads(testes),sperm- increasewithobstructionoflymphaticdrainage,duetoinflammatory,
aticcord,sexaccessoryglandsandexternalgenitalia.Thetestesperform traumaticorneoplasticconditionsofthetestis,resultinginahydrocele.
bothspermatogenicandsteroidogenicfunctions.Theuniqueanatomy
ofthereproductivetract,bothgrossandmicroscopic,isoptimally Vascular supply and lymphatic drainage
suitedforthesefunctionstobecarriedoutefficientlyandeffectively.
Arteries
TESTIS AND EPIDIDYMIS Thearterialsupplytothetestisandepididymisisderivedfromthree
sources.Indescendingorderofcontribution,thesearethetesticular
TESTIS artery(supplyingapproximatelytwo-thirdsofthetesticularblood
supply),thevasalartery(arterytovasdeferens,arterytoductusdefer-
Thetestesareovoidorgansresponsibleforspermandtestosterone ens,vasalartery,ductalartery)andthecremastericarteries(together
production.Inadults,theytypicallymeasure4–5cminlength,2–3cm supplyingapproximatelyone-thirdofthetesticularbloodsupply)(Fig.
inbreadthand3–4cminanteroposteriordiameter(Tishler1971);their 76.7)(HarrisonandBarclay1948,RamanandGoldstein2004).
weightvariesbetween12and20g.Averagetesticularvolumeranges
Testicular artery
from15to25ml(Prader1966,Goede2011).
Thetestesaresuspendedinthescrotumbythespermaticcord(Figs Thetesticularartery(internalspermaticartery)arisesfromtheabdomi-
76.2,76.3).Thelefttestisusuallylieslowerthantherighttestis;both nalaorta,inferiortotheoriginoftherenalartery,andcoursesinfero-
arepositionedobliquely,suchthattheupperpoleistiltedanterolater- laterallyundertheparietalperitoneum,alongpsoasmajor,towardsthe
allywhilethelowerpoleistiltedanteromedially.Thelocationofthe pelvis.Ontheright,itcoursesanteriortotheinferiorvenacavaand
testesinthescrotum,combinedwiththecharacteristicsofthescrotal posteriortothemiddlecolicandileocolicarteriesandtheterminal
skin,aswellasthecounter-currentheatexchangemechanismofthe ileum.Ontheleft,itcoursesposteriortotheinferiormesentericvein,
testicularpampiniformplexus,maintainsthetestesatatemperature leftcolicarteryandthedescendingcolon.Astherightandlefttesticular
3–4°Cbelowbodytemperature. arteriesenterthepelvis,theylieanteriortothegenitofemoralnerves,
Thetestesareenclosedinatoughcapsulemadeupofthreelayers: uretersandexternaliliacarteries.Botharteriesthenenterthedeep
aninnermosttunicavasculosa,anintermediatetunicaalbugineaand internalinguinalringandtravelwiththeipsilateralspermaticcordin
anoutertunicavaginalis(Fig. 76.4).Theposterioraspectofthetestis theinguinalcanaltothescrotum(seeFigs76.2,76.5).
isthesiteofattachmentoftheepididymisandis,therefore,onlypartly Initscoursetothetestis,thetesticulararterygivesoffoneormore
coveredbyserosa.Here,thetunicaalbugineaprojectsinwardstoform internalspermaticarteries,aninferiortesticularartery,andbranches
themediastinumtestis,andthetunicavaginalisprojectsoutwardsto supplyingthecaput,corpusandcaudaepididymis(Macmillan1954).
covertheepididymis.Withinthescrotum,thetestesareseparatedbya Thelevelatwhichthisbranchingoccursisvariable;in31–88%ofcases,
fibrousmedianseptum. itoccurswithintheinguinalcanal(Becketal1992,Jarowetal1992).
Atthelevelofthetestis,branchesofthetesticulararteryenterthe
Tunica vasculosa Thetunicavasculosacontainsaplexusofblood tunicaalbugineainthemediastinumtestisandramifyinthetunica
vesselsandlooseconnectivetissue.Itlinestheinnersurfaceofthe vasculosabeforereachingtheirdistribution.Ramificationofthetesticu-
tunicaalbuginea,aswellasallofthesurfacesandseptationswithinthe lararteriesoccursprimarilyintheanterior,medialandlateralportions
testis. ofthelowerpoleofthetestis,andintheanteriorsegmentoftheupper
pole(Jarow1991),whichhasimportantimplicationsforplanning
Tunica albuginea Thetunicaalbugineaisadense,blue–whitelayer testicularbiopsies.(Forfurtherreadingaboutvariationsintheorigin,
composedprimarilyofcollagenfibres.Itcoversthetunicavasculosa courseandnumberofthetesticulararteries,seeAsalaetal(2001),Pai
andissurroundedbytheviscerallayerofthetunicavaginalis.Atthe etal(2008)).
posterioraspectofthetestis,itprojectsinwardsasathickbutincom-
Vasal artery (artery to vas deferens, artery to
pletefibrousseptum–themediastinumtestis–whichextendsfrom
theuppertothelowerpoleofthetestis.Itisherethatvessels,nerves ductus deferens, deferential artery, ductal artery)
andtesticularductstraversethetesticularcapsule(Fig. 76.5). Thevasalarteryisabranchofthesuperior(and,occasionally,inferior)
vesicalartery,whicharisesfromtheinternaliliacartery.
Tunica vaginalis Thetunicavaginalisisacontinuationoftheperi-
tonealprocessusvaginalis,whoseformationprecedesthedescentofthe Cremasteric artery
fetaltestisfromtheabdomentothescrotum.Followingtesticular Thecremastericartery(externalspermaticartery)isabranchofthe
migrationintothescrotum,theportionoftheprocessusvaginalisthat inferiorepigastricartery.Itaccompaniesthespermaticcordandsup-
fallsbetweentheinternalinguinalringandthetestiscontractsandis pliesthecremasterandothercoveringsofthecord.Boththevasaland
obliterated,leavingadistalsaccontainingthetestis.Failuretoobliterate thecremastericarteriesentertheinguinalcanalatthedeepinguinal
theprocessusvaginalisresultsinapersistentcommunicationwiththe ring,andtravelthelengthofthespermaticcordalongsidethetesticular
scrotumandperitonealcavity(Fig. 76.6),whichcanleadtohydroceles artery.Thetesticulararteryandinternalspermaticveinsliewithinthe
andindirectinguinalhernias. internalspermaticfascia,whereasthevas(ductus)deferensandits
Thetunicavaginalisisreflectedfromthesurfaceofthetestisonto vessels,aswellasthecremastermusclesanditsvessels,lieoutsidethe
theinnersurfaceofthescrotum,formingvisceralandparietallayers internalspermaticfasciabutwithintheexternalspermaticfascia.Inthe
thatarecontinuousatbothpolesofthetestis.Theviscerallayercovers scrotum,arichvascularanastomosisoccursattheheadoftheepidi-
allaspectsofthetestis,excepttheposterioraspect,whereitisreflected dymis,betweenthetesticularandepididymalarteries,andatthetailof
towardstheepididymisbeforebecomingcontinuouswiththeparietal theepididymisbetweenthetesticular,epididymal,cremastericand
1272 layer.Theinnersurfaceoftheparietallayerhasasmooth,moist, vasalarteries. | 1,758 | 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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Thevolumeoftheleftandrighttestis,asmeasuredbyultrasono-
graphyinboysbetweeninfancyandadolescence,isshowninTable
76.1;referencecurvesformeantesticularvolumeareshowninFigure
76.1.
20
2.0
15
1.5
10
1.0
5
0.5
0 0
1 6 12
Age (years) Age (years)
Fig. 76.1 A, Reference curves for mean testicular volume measured by
ultrasound. P , P and P indicate tenth, fiftieth and ninetieth centiles,
10 50 90
respectively. B, Enlargement of the reference curves for mean testicular
volume measured by ultrasound. (With permission from Goede J, Hack
WW, Sijstermans K et al; Normative values for testicular volume measured
by ultrasonography in a normal population from infancy to adolescence.
Horm Res Paediatr. 2011;76(1):56–64.)
)lm(
emulov
sitseT
Table 76.1 Volume of the left and right testis, as measured by ultrasound in boys
between infancy and adolescence
Ultrasound (ml)
Age Boys Left SD Right SD Mean SD
(years) (n) volume volume volume
A B
1 40 0.48 0.14 0.48 0.13 0.48 0.13
P90
P90 2 38 0.47 0.09 0.45 0.1 0.46 0.09
3 36 0.52 0.18 0.5 0.13 0.51 0.15
4 38 0.52 0.18 0.5 0.15 0.51 0.16
P50
5 48 0.59 0.15 0.58 0.15 0.58 0.15
6 42 0.63 0.25 0.64 0.28 0.63 0.26
P10 P50 7 62 0.64 0.18 0.66 0.18 0.65 0.17
8 59 0.64 0.2 0.67 0.24 0.66 0.22
P10 9 53 0.78 0.46 0.8 0.48 0.79 0.46
10 49 0.95 0.51 0.99 0.52 0.97 0.51
11 60 1.31 0.95 1.35 1.14 1.33 1.03
12 55 2.31 1.8 2.35 1.79 2.33 1.77
18 1 2 3 4 5 6 7 8 9 1011 13 47 4.21 2.44 4.62 2.95 4.42 2.66
14 35 7.2 4.13 7.42 4.16 7.31 4.11
15 26 8.69 3.06 8.69 2.86 8.69 2.91
16 31 11.48 2.99 11.55 3.24 11.51 3.03
17 27 12.14 2.87 12.09 2.95 12.12 2.8
18 23 13.67 3.49 13.8 3.77 13.73 3.51
(SD = standard deviation)
(With permission from Goede J, Hack WW, Sijstermans K et al; Normative values for testicular volume
measured by ultrasonography in a normal population from infancy to adolescence. Horm Res Paediatr.
2011;76(1):56–64.) | 1,759 | 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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Fig. 76.2 The external male genitalia, ventral aspect.
Fundiform ligament of penis
Nerves and vessels exposed by extensive removal of
Suspensory
Dorsal artery of penis ligament of penis the skin and the superficial fascia of the penis. The
layers of the spermatic cord have been incised on the
Superficial
right; note the pampiniform venous plexus surrounding
inguinal ring
Spermatic cord the testicular artery. (With permission from Waschke J,
Ilioinguinal nerve
Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th
Testicular vein ed, Elsevier, Urban and Fischer. Copyright 2013.)
Spermatic cord
Genitofemoral nerve,
Cremasteric artery,
genital branch
cremasteric vein
Deep dorsal vein of penis
Dorsal nerve of penis
External pudendal
artery and vein
Pampiniform plexus
Vas deferens
Anterior scrotal branches
Testicular artery
Deep dorsal vein of penis
Deep fascia of penis
Superficial dorsal vein of penis
Subcutaneous tissue, Fig. 76.3 The external male genitalia,
Superficial inguinal ring, medial crus
fatty layer ventral aspect. The skin of the abdomen
and parts of the skin of the scrotum have
Internal oblique
been removed, and the body of the penis
Inguinal canal has been severed, revealing the internal
Ilioinguinal nerve structure of the penis. The layers of the
spermatic cord and the coverings of the
Superficial inguinal External oblique, testis have been dissected on the right.
ring, lateral crus aponeurosis (With permission from Waschke J, Paulsen
F (eds), Sobotta Atlas of Human Anatomy,
External spermatic 15th ed, Elsevier, Urban and Fischer.
fascia Copyright 2013.)
Cremasteric fascia, Deep dorsal vein of penis;
cremaster dorsal artery and
nerve of penis
Cavernous artery of penis
Corpus cavernosum
Urethra
Corpus spongiosum
Head
Epididymis
Appendix Cremasteric fascia, cremaster
Appendix of testis
Tunica vaginalis, visceral layer
External spermatic fascia
Tunica vaginalis, parietal layer
Dartos fascia
Internal spermatic fascia
(superficial fascia of scrotum),
Cremaster dartos muscle
External spermatic fascia Skin
Septum of scrotum Raphe of scrotum
theirvascularwalls,permittingtheexchangeofheatandsmallmole-
Veins
cules(Harrison1949),andfacilitatingthemaintenanceoflowertes-
Pampiniform plexus ticulartemperatures.Thepampiniformplexusascendsanteriortothe
Testicularveinsemergeposteriorlyfromthetestis,draintheepididymis, vasdeferens,andisdrainedby3–4veinsintheinguinalcanal.The
andunitetoformseveralhighlyanastomoticchannelssurroundingthe veinsentertheabdomenthroughthedeepinguinalringandcoalesce
testis,knownasthepampiniformplexus,amajorcomponentofthe intoasingletesticularveinthatdrainsintotheinferiorvenacavaon
spermaticcord(seeFig.76.2).Thisvasculararrangementmeansthat theright,andintotherenalveinontheleft.Therighttesticularvein
counterflowingarteriesandveinsareseparatedonlybythethicknessof joinstheinferiorvenacavaatanacuteangle,justinferiortothelevel | 1,760 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
MAlE REPRoduCTiVE sysTEM
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NoiTCEs
A
Head of
epididymis
Spermatic cord
Cremasteric fascia; cremaster
Mediastinum of Lobules of
Internal spermatic fascia Head of epididymis testis testis
Tunica vaginalis, parietal layer
Septa of
Appendix testis
testis
Appendix epididymis
Superior ligament of epididymis
Tunica
Upper pole Tail of epididymis albuginea
Sinus of epididymis
B
Posterior border Lateral surface
Pampiniform
Inferior ligament of plexus
epididymis Testicular
Anterior border artery
Tail of epididymis Efferent
ductules
Lower pole Head of
Tunica
epididymis
albuginea
Lobules of
Fig. 76.4 The left testis, exposed by incising and laying open the testis
cremasteric fascia and parietal layer of the tunica vaginalis on the lateral
aspect of the testis. (With permission from Waschke J, Paulsen F (eds),
Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban and Fischer.
Copyright 2013.)
Vas deferens
oftherenalveins,whilethelefttesticularveinjoinstheleftrenalvein
atarightangle(Fig. 76.8).Thetesticularveinscontainvalves. Body of epididymis
Lymphatic drainage
Testicularlymphaticflowisabundantandconsistent,andfollowsthe
generalretroperitonealschemeofverticaldrainage,withlateralflow Inferior aberrant
fromrighttoleft.Lymphaticvesselsfromtherighttestisdrainprimarily ductule
intotheinter-aortocavalnodesandparacavalnodes,withsomedrain- Septa of
testis
ageintotheleftpara-aorticnodes.Lymphaticvesselsfromthelefttestis
drainintotheleftpara-aorticandinter-aortocavalnodes.
Tail of epididymis
Innervation
Fig. 76.5 A, A vertical section through the testis and epididymis. B, The
Thetestisisinnervatedeitherbynervefibresthatarisefromthetenthand arrangement of the ducts of the testis and the mode of formation of the
vas deferens. (With permission from Waschke J, Paulsen F (eds), Sobotta
elevenththoracicspinalsegments,viatherenalandaorticplexuses,and
Atlas of Human Anatomy, 15th ed, Elsevier, Urban and Fischer. Copyright
accompanythetesticularvessels,orbyfibresthatarisefromthepelvic
2013.)
plexusandaccompanythevasdeferens(Rauchenwaldetal1995).Inter-
estingly,someafferentandefferentnerveshavebeenshowntocrossover
tothecontralateralpelvicplexus(Taguchietal1999),whichmaybeone epitheliumthatalsocontainsnon-ciliated,activelyendocyticcells.
reasonwhypathologicalprocessesinonetestiscanaffecttheother. Outsidetheepitheliallining,theductulesaresurroundedbyathin
circularcoatofsmoothmuscle.
Microstructure
Thereisareductioninthediameteroftheseminiferoustubules
duringthethirdtrimesterofpregnancyandimmediatelybeforebirth,
Thetestisisenclosedwithinatough,collagenoustunicaalbuginea, whichisfollowedbyagradualincreaseinthediameterthroughout
whichthickensposteriorlyasthemediastinumtestis.Bloodvessels, childhood(MendezandEmery1979).Seminiferoustubulesarerespon-
lymphaticsandgenitalductsallenterandleavethetestisatthemedia- sibleforupto80%ofthetotaltesticularvolume.Itisestimatedthat
stinum(Fig. 76.9).Septationsoriginatingatthemediastinumtestis thecombinedlengthofthe600–1200tubulesinthehumantestisis
extendinternallytopartitionthetestisintoapproximately250lobules approximately250metres.Eachtubuleissurroundedbyabasallamina,
thatdifferinsize,thelargestandlongestlobulesbeingnearthecentre restingonacomplex,stratifiedepithelium.Incross-section,thelumen
(seeFig.76.5).Eachlobulecontains1–4convolutedseminiferous oftheseminiferoustubuleislinedbySertolicells,andcontainssperm-
tubulesandinterstitialtissuecomposedofLeydigcells,mastcells, atozoainvariousstagesofdevelopment,fromspermatogonialstem
macrophages,nervesandbloodvessels. cellsnearthebase,toprogressivelymatureforms(spermatogonia,
Seminiferoustubulesaretypicallylong,highlycoiledandlooped; spermatocytes,spermatidsandspermatozoa)arrangedinasystematic
bothendsterminateinthemediastinumtestis.Spermatogenesisoccurs fashiontowardsthecentreofthetubule.Residualbodies,spherical
inthehighlycoiledportions(Fig. 76.10).Asthetubulesreachthe structures derived from surplus spermatid cytoplasm shed during
apicalportionofthelobulenearthemediastinum,theybecomemuch spermatozoalmaturation,maybefoundamongthespermatids.
lessconvolutedandformshorttubulirecti,whichlackspermatogenic SpecializedtightjunctionalcomplexesbetweenadjacentSertolicells
cellsandare,instead,linedbycuboidalepithelium.Withinthemedia- formafunctional‘blood–testisbarrier’thatsubdividestheseminiferous
stinumtestis,tubulirectianastomosetoformtheretetestis,whichis epitheliumintobasalandadluminalcompartments.Spermatogonia
linedbyaflatepithelium.Here,tubularfluidisreabsorbedandsperm- anddevelopingspermatocyteslieoutsidetheblood–testisbarrier,in
atozoabecomeconcentrated.Theretetestiscoalescestoform7–15 thebasalcompartment,whereasmaturespermatocytesandspermatids
efferentductules,whichactasconduitstocarryspermatozoaintothe are sequestered above the blood-testis barrier, in the adluminal
caputepididymis.Theefferentductulesarelinedbyaciliatedcolumnar compartment. | 1,761 | 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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Thelongerlengthofthelefttesticularveinanditsangleofinsertion
intotheleftrenalveinhavebeensuggestedaspossibleaetiologiesfor
theoccurrenceofvaricoceles.Additionally,thetesticularveinsmay
anastomosewiththeexternalpudendal,cremastericandvasalveins,
allowingvaricocelestopersistorrecurafterablativeproceduresthatdo
notaddressthesepotentialcollaterals. | 1,762 | 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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Fig. 76.6 A
laparoscopic view of a
persistent
communication
between the scrotum
and peritoneal cavity in
a 4-month-old boy
(patent processus
vaginalis).
2
3
Patent Right vas Right testicular
processus deferens vessels
vaginalis 4
1
Cremasteric artery Testicular artery and vein
Pampiniform plexus
Vasal artery
Head of epididymis
Fig. 76.8 A multislice computed tomogram of the inferior vena cava,
showing the left testicular vein draining to the left renal vein, and the right
Tail of epididymis
testicular vein draining directly to the inferior vena cava. Key: 1, right
testicular vein; 2, inferior vena cava; 3, left renal vein; 4, left testicular
vein.
Fig. 76.7 The arterial blood supply and venous drainage of the testis.
(With permission from Waschke J, Paulsen F (eds), Sobotta Atlas of
Human Anatomy, 15th ed, Elsevier, Urban and Fischer. Copyright 2013.)
Spermatogonia Spermatogonia,thegermcellsforallspermatozoa,
aredescendedfromprimordialgermcellsthatmigrateintothegenital
cordsofthedevelopingtestis.Inthefullydifferentiatedtestis,theyare
locatedalongthebasallaminaeoftheseminiferoustubules(Fig.
76.10B).Basedontheircellularandnucleardimensions,distribution
ofnuclearchromatin,andhistochemicalandultrastructuralproperties,
spermatogoniaarecharacterizedaseitherdark-typeA(Ad),pale-typeA
(Ap)ortypeB.Adspermatogoniadividemitoticallytomaintaintheir
ownpopulation,andcandifferentiatetogiverisetoApcells,theprecur-
sorsoftypeBcells,whicharecommittedtothespermatogenesiscycle.
TypeBcellsgiverisetotypeIspermatocytes;theyleavethebasalcom-
partmentoftheseminiferoustubuleandcrosstheblood–testisbarrier
toentertheadluminalcompartmentinastepcoordinatedbySertoli
cells.
Thegenerationofmaturespermatozoafromspermatogoniatakes Fig. 76.9 A colour Doppler scan of the scrotal contents showing normal
approximately64days.Incross-section,aseminiferoustubuleshows flow. The linear echogenic band (arrow) seen centrally represents the
morethanonephaseofthecyclearounditscircumferencebecause mediastinum testis, which is composed of fibrofatty material.
wavesofprogressionthroughaspermatogeniccycleoccurinspirals
alongthelengthofatubule(seeFig.76.10B).
proportionofspermatidsdegenerateduringmaturation,reducingthe
Primary and secondary spermatocytes Primaryspermatocytes expectedyield.
haveadiploidchromosomenumber,withduplicatedsisterchromatids
(4NDNAcontent).Theyarelargecellswithroundnuclei,inwhichthe Spermatids Spermatidsundergoaseriesofnuclearandcytoplasmic
chromatiniscondensedintodark,thread-like,coiledchromatids.They changes,termedspermiogenesis,inordertodevelopintomaturesper-
undergomeiosisItogiverisetosecondaryspermatids(2N),which matozoa.Thesechangestakeplacewhilethespermatidsareclosely
rapidlyundergomeiosisIItoformhaploidspermatids(N).Theoreti- associatedwithSertolicells,andlinkedtooneanotherbycytoplasmic
cally,eachprimaryspermatocyteproducesfourspermatids;however,a bridges.Spermiogenesisincludesthedevelopmentoftheacrosome | 1,763 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
MAlE REPRoduCTiVE sysTEM
1276
8
NoiTCEs
Acrosomal cap
Head 4 µm
ST Nucleus
Centriole Neck 0.3 µm
Spiral mitochondria
Middle piece 7 µm
L
Axoneme
Principal piece 40 µm
A
L
M
End piece 5–7 µm
S
SC
SZ Fig. 76.11 The main ultrastructural features of a mature spermatozoon.
ST
tened nucleus with condensed, dark-staining chromatin, covered
SG anteriorlybyanacrosomalcap.Thelattercontainsacidphosphatase,
hyaluronidaseandproteasesnecessaryforoocytefertilization.Thehead
isconnectedbyashortneck,approximately0.3µminlength,toalong
tail,whichisdividedintomiddle,principalandendpieces.Themid-
B
pieceofthetailisalongcylinder,approximately7µminlength.It
consistsofanaxialbundleofmicrotubules,theaxoneme,surrounded
Fig. 76.10 A, Seminiferous tubules (ST; cut in various planes of section)
byacylinderofninedenseoutermicrotubules,surroundedbyahelical
and the interstitial tissue (Leydig cells, L) of the testis. The seminiferous
mitochondrialsheath.Themid-pieceisthepowerhouseofthesperma-
tubules are highly convoluted and lined by a stratified epithelium,
tozoon.Theprincipalpieceofthetailisresponsibleformotility.With
which consists of cells in various stages of spermatogenesis and
spermiogenesis (collectively referred to as the spermatogenic series). alengthof40µmandadiameterof0.5µm,thetailformsthemajority
Non-spermatogenic cells are the Sertoli cells. B, A human seminiferous ofthevolumeofaspermatozoon.Theaxonemalcomplexiscontinuous
tubule showing the differentiation sequence of spermatozoa from basally fromtheneckregiontotheterminusofthetail,withonlytheaxoneme
situated spermatogonia (SG). Large primary spermatocytes (SC) have persistinginthefinal5–7µm.
characteristic thread-like chromatin in various stages of prophase of the
first meiotic division. Smaller haploid spermatids (ST) have round nuclei Sertoli cells Sertolicellshaveeuchromaticandirregularnucleithat
initially, but mature to possess the dense, elongated nuclei and flagella arealignedperpendiculartothebasallaminaandcontainoneortwo
of spermatozoa (SZ). Sertoli cells (S) are identified from their oval or prominentnucleoli.Theyarevariableinshape.Theirbasalendrestson
pear-shaped nuclei, orientated perpendicular to the basal lamina, and thebasallamina,whiletheirapicalendextendsintothetubulelumen.
from their prominent nucleoli. The tubule is surrounded by peritubular Consistentwiththeirphagocyticfunction,theircytoplasmisrichin
myoid cells (M). Clusters of large endocrine Leydig cells (L) are seen in lysosomes.Sertolicellsprovidekeysupportforspermatogenesiswithin
the interstitial connective tissue. theseminiferoustubules.Complexrecessesintheirplasmamembranes
servetoenvelopspermatogonia,spermatidsandspermatozoa,untilthe
latterarematureenoughforrelease.Longcytoplasmicprocessesextend
fromGolgivesicles,generationoftheaxonemefromthecentrioles,and betweenspermatogoniainthebasalcompartmentandspermatocytes
formationoftheacrosomalcapattheanteriorpoleofthespermato- intheadluminalcompartmentoftheseminiferoustubule.Adjacent
zoon.Concurrently,thenuclearchromatincondensesandthenucleus Sertolicellsarejoinedatthislevelbytightjunctionsthatcreateadif-
assumesaspearheadshape.Thecytoplasmicvolumeshrinks,bringing fusionbarrierbetweentheextratubularandintratubularcompartments.
thewalloftheacrosomalvesicleintocontactwiththeplasmamem- Thisso-calledblood–testisbarriercanbedisruptedbytraumaticor
brane.Aperinuclearsheathofmicrotubulesdevelopsfromtheposte- inflammatory events, allowing self-directed immune responses to
rioredgeoftheacrosomeandextendstowardstheposteriorpoleofthe developagainstspermantigens,potentiallyleadingtosubfertility.
spermatozoon.Here,themicrotubulesarearrangedinthetypicalflagel- Inadditiontotheirroleinspermatogenesis,Sertolicellssecrete
larpatternofnineoutermicrotubulessurroundingtwocentralmicro- proteinaceousfluidtofacilitatespermatozoaltransportthroughthe
tubules,theaxonemalcomplexthatextendslongitudinallytoformthe seminiferoustubulesandintotheexcurrentducts.Theyalsoregulate
tailofthespermatozoon.Mitochondriamigratealongtheaxonemal theintratesticularhormonalmilieubysecretinginhibinBandandro-
complexandconcentrateinthemid-pieceofthetail.Inthefinalphase gen binding protein in response to stimulation by pituitary
ofspermiogenesis,excesscytoplasmisdetachedfromthespermato- gonadotropins.
zoonasaresidualbodythatisphagocytosedanddegradedbySertoli
cells.Duringtheformationofresidualbodies,spermatidslosetheir Leydig cells and interstitial tissue Theinterstitialtissuebetween
cytoplasmicbridges,andseparatefromoneanother,beforebeing seminiferoustubulesincludesperitubularmyoidcells,vessels,nerves
releasedintothelumenoftheseminiferoustubule. andclustersofLeydigcells.Myoidcellsarecontractile;theirrhythmic
activityhelpspropelnon-motilespermatozoathroughtheseminiferous
Spermatozoa Spermatozoareleasedintotheseminiferoustubuleare tubulestowardstheretetestisandexcurrentductalsystem.Leydigcells
structurallymaturebutusuallynon-motile.Inthepresenceofexcurrent arelargepolyhedralcellswitheccentricnucleicontaining1–3nucleoli,
ductalobstruction,testicularspermcanacquiremotility(Jowetal andpale-stainingcytoplasmcontainingsmoothendoplasmicreticu-
1993).Theshapeofthespermatozoonisideallysuitedforrapidpro- lum,lipiddroplets,andcharacteristicneedle-shaped,crystalloidinclu-
gressivemotility(Fig. 76.11).Itsheadhasminimalcytoplasmand sions(crystalsofReinke).Inresponsetostimulationbypituitary
measuresapproximately4µm×3µm.Itcontainsanelongated,flat- gonadotropins,theysynthesizeandsecretetestosterone. | 1,764 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Testis and epididymis
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Age-related changes Functionally,thefetaltestisisprimarily inguinalring,intheinguinalcanal,orbetweenthesuperficialinguinal
anendocrineorganthatproducestestosteroneandanti-Müllerian ringandthescrotum.Retentionintheinguinalcanalisassociatedwith
hormone.Seminiferoustubulesdonotbecomecanalizeduntilapproxi- apatentprocessusvaginalis,andmaybefurthercomplicatedbyacon-
matelytheseventhmonthofgestation.FetalLeydigcells,responsible genitalhernia.Occasionally,thetestismaymigrateoutsideitsnormal
forandrogen-induceddifferentiationofmalegenitalia,degenerateafter pathofdescent,andlieinanectopiclocation.
birth.AsecondwaveofLeydigcelldifferentiationoccurs2–3months Atbirth,3%offull-termmaleinfantshaveaunilateralundescended
afterbirth,brieflyelevatingtestosteronelevelsinmaleinfants.The testis.By6monthsofage,thisnumberdecreasestolessthan1%.Unde-
Leydigcellsofearlyinfancysubsequentlyregressandthetestisremains scendedtestesareassociatedwithahigherriskofinfertilityandtesticu-
inastateofdormancyduringchildhood.InastudyofJapaneseboys, larcancerlaterinlife.
gonocyteswerereportedtoappearatabouttheageof2years,sperma- Incontrast,maldescentinchildrenbetweentheagesof1and
tocytesby4yearsandspermatidsby11years(Yuasaetal2001). 15yearsisassociatedwithSertolicelldegeneration(Runeetal1992).
Pubertyisassociatedwiththedevelopmentofanadultpopulation
ofandrogen-producingLeydigcells,whichpersistthroughoutadultlife. Retractile testis
Thetestesgrowslowlyinsizeuntiltheageof10or11years,atwhich
timethereisamarkedaccelerationofgrowthrate.Thisincreasein Available with the Gray’s Anatomy e-book
testicularsizeislargelyduetotheonsetofspermatogenesis,character-
izedbyproliferationanddifferentiationofpreviouslydormantsperma- Torsion
togonialstemcells.Testicularsize,spermqualityandquantity,andthe
numbersofSertoliandLeydigcellshaveallbeenreportedtodecline Available with the Gray’s Anatomy e-book
withage,althoughnoconsistentordefinitiveagefortheonsetofthis
declinehasbeenidentified.Testicularvolumeoccupiedbyseminiferous
Hydrocele
tubulesdecreases,whereasthatoccupiedbyinterstitialtissueremains
approximatelyconstant.
Available with the Gray’s Anatomy e-book
Themostfrequentlyobservedhistologicalchangeintheageingtestis
istheapparentvariabilityinspermatogenesis;spermatogenesisiscom-
pleteinsomeareas,andreducedinothers,orabsentaltogetherasa Splenogonadal fusion
resultoftubularsclerosis.Intubuleswherespermatogenesisiscom-
plete,morphologicalabnormalities,suchasmultinucleation,maybe Available with the Gray’s Anatomy e-book
observedinthegermcells.Germcellloss,beginningwithspermatids,
andprogressivelyaffectingtheearlierstagesofspermatogenesis,can Transverse/crossed testicular ectopia
alsobeseen.Asaresult,bothspermqualityandquantitymaybe
affected.Insomemen,thischangeisnotableasearlyasthethirdor Available with the Gray’s Anatomy e-book
fourthdecadeoflife.
Sertolicellsarealsoaffectedbyageing,andshowarangeofmor-
Polyorchidism
phologicalchangesincludingde-differentiation,mitochondrialmeta-
plasia,andmultinucleation.InLeydigcells,thereisadeclineinthe
Available with the Gray’s Anatomy e-book
numberofmitochondriaandthequantityofsmoothendoplasmic
reticulum,paralleledbyanincreaseinlipiddroplets,crystallineinclu-
sionsandresidualbodies.Somecellsmayalsobecomemultinucleated.
Functionally,thesechangesaremanifestedasanage-relatedgradual EPIDIDYMIS
declineincirculatingtestosteronelevels.
Theepididymisliesposterior,andslightlylateral,tothetestis.Anatomi-
Sperm motility and maturation Humanspermatozoaacquirean cally,itisdividedintothreesections:caput(head),corpus(body)and
increasedcapacityformotilityastheymigratethroughtheepididymis, cauda(tail).Between8and12efferentductulesfromthesuperiorpole
whichismanifestednotonlyasaquantitativeincreaseinthepercentage ofthetestisdrainintoandformthecaputepididymis.Distally,the
ofspermatozoawithmotiletails,butalsoasaqualitativechangefrom caudaepididymisbecomescontinuouswiththeconvolutedportionof
animmaturetoamorematurepatternofmotility.Spermatozoainthe thevasdeferens(seeFig.76.5B).Theepididymisisinvestedbytunica
proximalepididymisdemonstratehigh-amplitude,low-frequencytail vaginalis,continuouswiththatcoveringthetestis.Laterally,adeep
movements,producinglittlemotion.Thisisincontrasttospermatozoa groove,thesinusepididymis,markstheboundarybetweenthetestis
inthecaudaepididymis,whichdemonstratelow-amplitudeandhigh- andepididymis.Testis–epididymisnon-fusionhasbeendescribedin
frequencytailmovements,resultinginconsiderablygreaterforward childrenwithcryptorchidism;non-fusionmayinvolvetheepididymal
progression(Bedfordetal1973). headortail,orthewholeepididymis(Kraftetal2011).
Whether,andtowhatextent,spermmotilityisdependentonthe
interactionofhumanspermatozoawithaparticularsectionofthe Epididymal cyst and spermatoceles
epididymisisunknown.Inpatientswithcongenitalabsenceorobstruc-
tionofthevasdeferens,spermatozoainthedistalepididymisdemon- Available with the Gray’s Anatomy e-book
strate worse motility compared to spermatozoa in the proximal
epididymis(Silber1989,SchoysmanandBedford1986).Therefore,
Microstructure
intrinsicspermprocesses,aswellasintrinsicepididymalfunction,
appeartoplayanimportantroleinspermmaturation.
Followingejaculation,spermatozoadisplaytheirfullpatternofmo- Theepididymaltubuleis3–4metresinlength(Turneretal1978),and
tility.Althoughspermmotilityishighestinthehoursfollowingejacula- isentirelyencapsulatedbythetunicavaginalis.Extensionsfromthis
tion,motilehumanspermatozoahavebeenrecoveredfromcervical connectivetissuesheathentertheinterductalspaces,formingseptathat
mucusseveraldaysafterinsemination.However,thissurvivalperiod dividethetubuleintohistologicallysimilarregions(Kormanoand
maybeoflittlerelevance,giventhathumanspermatozoaarecapableof Reijonen1976).Thecaputepididymisconsistsof8–12efferentducts
migratingtotheirtubaldestinationwithinanhourofinsemination. andtheproximalsegmentoftheductusepididymis.Theefferentducts
Afterenteringthefemalereproductivetract,spermatozoaundergoa becomelargerandmoreconvolutedthantheyareinthetestis.Each
processknownascapacitation,torenderthemcapableoffertilizingthe ductis15–20cminlength,andopensintoanindividualepididymal
oocyte.Capacitationinvolvesanumberofstructuralandbiochemical tubule.Thetubulesanastomosewithoneanotheralongthelengthof
changes,includingthedevelopmentofhyperactivatedmotilityand theepididymis,eventuallybecomingasingle,coiledtubuleinthe
completionoftheacrosomereaction.Independentofothersperm corpusepididymis.Theyaresurroundedbycontractilesmoothmuscle
characteristicssuchasmotilityandmorphology,capacitationisaneces- cells(Fig. 76.13),whichincreaseinsizeandnumberinthedistal
sarystepforthedevelopmentoffunctionalspermatozoa. epididymis.Peristalticcontractionsgeneratedbythesmoothmuscle
propelthespermatozoainanantegradedirectiontowardsthecauda.
Developmental anomalies of the testis Epithelium Theepithelialliningoftheepididymaltubulecontains
principal,basal,apicalandclearcells.Principalcellsaretallcolumnar
Cryptorchidism Testiculardescentfromtheabdominalcavitytothe cells with basally located, oval nuclei. They bear long stereocilia
scrotummaybearrestedatanypointalongitscourseatthedeep (15µm),andfunctiontoresorbtesticularfluid;approximately90%of | 1,765 | 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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Orchidopexyis,therefore,recommendedforpatientswithpersistent Gangrene of appendix testis
cryptorchidismafter6monthsofageandwithin18monthsofage. secondary to torsion
Availableevidencesuggeststhatorchidopexyatanyagemayimprove
spermatogenesis(Shinetal1997),butdoesnotdecreasetheriskof
testicularcancerinacryptorchidtestis.Aninverserelationshiphasbeen
reportedbetweenageatorchidopexyandtotalspermcountandsperm
motility.Thedataareinsupportoforchidopexyinthefirstyearoflife
(Canaveseetal2009).Nevertheless,surgicalcorrectiondoesmaximize
thechanceofearlydetectionofatesticularmass,andistheonlymeans
ofrestoringanormalmilieuforspermatogenesistooccur.Interestingly,
Leydigcellfunctionisusuallyunchangedbymaldescent,soserum
testosteronelevelsremainwithinthenormalrangeinaffectedpatients.
Retractiletestesareseenmorecommonlythanundescendedtestesin
boys.Aretractiletestisisonethatmovestoandfrobetweenthegroin
andthescrotum.Unlikeundescendedtestes,retractiletestescanbe
manipulatedtothelowerpartofthescrotumonclinicalexamination.
Retractiletestesaresmallerthannormaltestes,havingameanvolume
of0.50mlinchildren.
Testiculartorsionreferstorotationofthetestisarounditsbloodsupply,
leadingtotesticularischaemia.Torsionmaybeextravaginalorintra-
vaginal,dependingonwhetheritinvolvesarotationofboththetestis
andthetunicavaginalis,orofthetestisalone,withinanintacttunica
vaginalis.Ineithercase,torsionresultsinseverescrotalpainsecondary Fig. 76.12 Gangrene of the appendix testis secondary to torsion in an
totissueischaemia.Fertilitycanbeaffectedbyasingleepisodeof 8-year-old child.
torsion.Ifunrelievedwithin4–6hours,permanenttissuelosscanoccur.
Testiculartorsionisthereforeconsideredasurgicalemergency.
Otherstructuresinthescrotum,suchastheappendixtestis(hydatid
ofMorgagni)(Fig. 76.12)andappendixepididymis(seeFig.76.4),can
alsoundergotorsion,resultinginscrotalpainthatmaybedifficultto Transverse/crossedtesticularectopiaisanextremelyrareconditionin
differentiatefromtesticulartorsion.Insomeinstances,a‘bluedot’sign whichbothtestesdescendintoasingleinguinalcanalorhemiscrotum.
isnotedattheupperpoleofthetestis,whichisdiagnostic.Thesestruc- Theoriginofthespermaticcordisnormallylocatedoneachside.It
turesaredevelopmentalremnantsoftheparamesonephric(Müllerian) mayoccurinassociationwithpersistentMüllerianductsyndrome
ductandthemesonephros,respectively.Therearenoassociatedlong- (Tiryakietal2005).
termsequelae.
Polyorchidismisararecongenitalanomalyinwhichtherearetwoor
Apatentprocessusvaginalisallowscommunicationbetweentheperi- moretestes.Themostcommontypeconsistsofthreetestes;caseswith
tonealcavityandthespermaticcordorscrotum.Passageofperitoneal fourtesteshavealsobeenreported.Thesupernumerarytestesmayor
fluidintothescrotumpresentsasacommunicatinghydrocele,and maynotbeconnectedtoavasdeferens.
usuallyresolvesspontaneouslyoncetheprocessusisobliterated,by
18–24monthsofage.Alternatively,iftheprocessusispatentproximally Epididymalcystsarisefromtheepididymaltubulesandmayoccur
butobliterateddistally,ahydroceleorcystofthecordmaybenoted. anywhereinthecaput,corpusorcaudaepididymis.Ifasymptomatic,
Surgicaltreatmentmaybeindicatedforpersistent,non-communicating removalisunnecessary,particularlygiventheriskofiatrogenicepidi-
hydroceles.Hydrocelecanalsooccurasaresultoflymphaticobstruc- dymalobstruction.Spermatocelesarecyststhatare,basically,aneu-
tionfromtesticulartumour,epididymitis,orchitisortrauma.A20% rysmsoftheefferentductsthatformthecaputepididymisandcontain
incidenceofhydrocelehasbeenreportedinchildrenhavinglaparo- sperm.Removalisunnecessaryunlesstheygrowtoalargesizeand
scopicen blocligationofthespermaticvesselsontheposteriorab- causepain(Kaufmanetal2011).However,spermatocelesmaybeaspi-
dominalwall(Palomoprocedure).Thiscomplicationisavoidedby ratedasasourceofspermatozoa.
lymphatic-sparingsurgery(Schwentneretal2006).
Splenogonadalfusionisararecongenitalanomalycharacterizedby
splenictissuebeingconnectedtothegonad,resultingfromanabnor-
malconnectionbetweenthespleenandthegonadduringgestation.It
hasahigherpredominanceinmalesandisalmostinvariablyonthe
leftside.Itmaybeofthecontinuoustype,wherethetestisisconnected
tothemainspleen,orofthediscontinuoustype,wherethetestisis
connectedtoectopicsplenictissue. | 1,766 | 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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thetotalsecretoryfluidvolumeisabsorbedintheepididymis.Theyalso deriveddirectlyfromtheinternaliliacartery.Veinsfromthevasand
endocytoseothercomponentsofseminalfluidandproduceglycopro- seminalvesiclesdraintothepelvicvenousplexus,whereastheassoci-
teinsthatareessentialforspermmaturation.Basalcellsliebetweenthe atedlymphaticvesselsdrainintotheexternalandinternaliliacnodes.
basesoftheprincipalcellsandarethoughttobeprecursorsofprincipal
cells.Apicalandclearcellsarefarlesscommonthanprincipalandbasal Innervation
cells.Apicalcellsarerichinmitochondriaandaremostabundantin
thecaputepididymis.Incontrast,clearcellsarecolumnarandmost
Thevasadeferentiaareinnervatedbyarichautonomicplexusofpri-
abundantinthecaudaepididymis.Theyhavefewmicrovillibutnumer-
marilypostganglionicsympatheticfibresderivedfromthepelvicplexus.
ousendocyticvesiclesandlipiddroplets.Theirfunctionsareunknown.
Microstructure
VAS DEFERENS, SPERMATIC CORD,
PARADIDYMIS AND EJACULATORY DUCT Inhumans,thevasdeferensis30–35cminlengthand2–3mmin
diameter,withaluminaldiameterof300–500µm.Incross-section,it
consistsofanouteradventitialsheathcontainingbloodvesselsand
VAS DEFERENS
nerves;athick,three-layeredmuscularwallofinnerandouterlongitu-
dinalandmiddlecircularsmoothmuscle;andaninnermucosallining
Thevasdeferens(ductusdeferens)isatubularstructurederivedfrom
ofpseudostratifiedcolumnarepitheliumwithnon-motilecilia(Fig.
themesonephricduct.Itsprimaryfunctionisthetransportofsperm
76.14).Ithasthegreatestmuscletolumenratio(approximately10:1)
fromtheepididymistotheurethra,althoughabsorptiveandsecretory
ofanyhollowviscusinthebody.Duringejaculation,thesmooth
functionshavealsobeendescribed(Hoffer1976).Asitarisesfromthe
musclelayerscontractreflexively,propellingthesperminanantegrade
caudaepididymis,thevasistortuousfor2–3cm(seeFig.76.5B).
direction(seeabove).
Beyondthisconvolutedsegment,itliesposteriorandparalleltothe
vesselsofthespermaticcord,passesthroughtheinguinalcanal(seeFig.
Developmental anomalies
76.16),andemergesinthepelvislateraltotheinferiorepigastricvessels
of the vas deferens
(seeFig.61.3).Attheinternalring,thevasdivergesfromthetesticular
vessels,coursingmedialtothestructuresofthepelvicsidewall,inorder
toreachthebaseoftheprostateposteriorly.Here,thevasonceagain
Available with the Gray’s Anatomy e-book
becomestortuousanddilated(theampullaofthevasdeferens),before
culminatingattheejaculatoryduct(seeFig.74.23).
SPERMATIC CORD
Vascular supply and lymphatic drainage
Thespermaticcordbeginsatthedeeporinternalinguinalring,extends
Thevasdeferensissuppliedbythevasalartery,whichisusuallyderived
thelengthoftheinguinalcanal,exitsthecanalatthesuperficialor
fromthesuperiorvesicalartery,andoccasionallyfromtheinferior
externalinguinalring,andsuspendsthetestisinthescrotum(Fig.
vesicalartery,bothbranchesoftheinternaliliacartery.Rarely,itis
76.15;seeFig.76.3).Betweenthesuperficialinguinalringandthetestis,
thecordliesanteriortothetendonofadductorlongus.Itisflanked
anteriorlybythesuperficialexternalpudendalartery,andposteriorly
bythedeepexternalpudendalartery.Theilioinguinalnerveliesinferior
tothecordasittraversestheinguinalcanal.
Inadditiontotheartery,veins,lymphaticsandnervessupplyingthe
testis,whicharecontainedwithintheinternalspermaticfascia,the
ET spermaticcordincludestheilioinguinalnerve,thegenitalbranchof
thegenitofemoralnerve,thecremastericartery,veinsandlymphatics,
andthevasalartery,veinsandlymphatics,allofwhicharecontained
withintheexternalspermaticfascia(Fig. 76.16;seeFig.76.2).These
fasciallayersarecontinuouswiththelayersoftheabdominalwall.The
internalspermaticfasciaisderivedfromthetransversalisfascia,and
formsathin,looselayeraroundthespermaticcord.Thecremasteric
FCT fascia,whichcontainstheskeletalmusclefibresthatmakeupthecre-
mastermuscle,isderivedfrominternaloblique.Theexternalspermatic
fasciaiscontinuouswiththeaponeurosisofexternaloblique.
Ectopicsuprarenaltissue(adrenalrest)isencounteredwithinthe
distalendofthespermaticcordin2%ofchildrenundergoinginguinal
procedures.Adrenalrestsaretypicallybrightyellowtoorangeincolour,
roundorovalinshape,andupto5mmindiameter;theycontainthe
Fig. 76.13 The microstructure of the epididymis. Abbreviations: ET, threelayersofthesuprarenal(adrenalcortex)butnomedulla(Savaset
epididymal tubule; FCT, fibromuscular connective tissue. al2001).
Fig. 76.14 The vas deferens. A, A low-power view,
transverse section. B, A higher-power view. The
convoluted lumen is lined by pseudostratified
columnar epithelial cells.
A B | 1,767 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Male reproductive system
1278.e1
67
RETPAHC
Thevasdeferensmaybecongenitallyabsent,eitherunilaterallyor
bilaterally.Whenbilateral,theconditionisassociatedwithamutation
ofthecysticfibrosistransmembraneconductancegenein80%of
affectedmen.Thisconditionischaracterizedbylowsemenvolumedue
toabsentorhypoplasticseminalvesiclesandazoospermia,although
spermatogenesisisusuallynormal.Absentvasaisusuallytheonly
genitalmanifestationofcysticfibrosis.
Theanatomyofthevasdeferensisworthyofnoteinchildrenwith
cryptorchidism(seeabove).Atlaparoscopicorchidopexyforintra-
abdominaltestis,itisimportanttoexcludea‘loopingvasdeferens’that
enterstheinguinalcanalandloopsbacktotheabdominalcavity
(Shalabyetal2011);failuretorecognizethisanatomicalanomalymay
resultiniatrogenicinjurytothevasdeferens. | 1,768 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Accessory glandular structures
1279
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RETPAHC
Fig. 76.15 The relationship of
the spermatic cord to the
External oblique
External oblique anterior abdominal wall. (With
permission from Waschke J,
Paulsen F (eds), Sobotta Atlas
of Human Anatomy, 15th ed,
Linea alba Elsevier, Urban and Fischer.
Copyright 2013.)
External oblique,
Internal oblique
aponeurosis
Inguinal ligament
Cremaster
Intercrural fibres
Reflected ligament
Lateral crus
Superficial
Fundiform ligament Medial crus inguinal ring
of penis
Spermatic cord
Fig. 76.16 Structures contained within the
spermatic cord. (With permission from Waschke
J, Paulsen F (eds), Sobotta Atlas of Human
Anatomy, 15th ed, Elsevier, Urban and Fischer.
External oblique, Copyright 2013.)
aponeurosis
Internal oblique
Deep inguinal ring
Transversus
Inferior epigastric
abdominis
arteries and veins
Ilioinguinal nerve
Transversalis fascia
Transversalis fascia
Ilioinguinal nerve Artery of vas deferens
Vas deferens
Superficial inguinal ring
Pampiniform plexus
Genitofemoral nerve, genital branch
Genitofemoral nerve,
genital branch Cremaster
Inguinal ligament
External spermatic fascia
PARADIDYMIS diameterofgreaterthan2.3mmdefinesadilatedorobstructedefferent
duct(Nguyenetal1996).
Theparadidymis(organofGiraldes)isasmallcollectionofconvo-
lutedtubuleslocatedanteriorlyinthespermaticcord,justabove
ACCESSORY GLANDULAR STRUCTURES
thecaputepididymis.Thetubulesarelinedwithcolumnarciliated
epitheliumandarelikelytorepresentavestigialremnantofthe
mesonephros. SEMINAL VESICLES
Theseminalvesiclesarepairedoutpouchingsoftheterminalvasdefer-
EJACULATORY DUCTS ens,locatedatthebaseoftheprostate,betweenthebladderandthe
rectum(Fig. 76.17,seeFig.74.23).Inadults,theseminalvesiclemeas-
Thepairedejaculatoryductsareformedfromtheunionoftheductof uresbetween5and10cminlength,and3and5cmindiameter,with
theseminalvesiclewiththeampullaofthevasdeferens.Eachisapprox- anaveragevolumecapacityof13ml(Goldstein2012).Inthemajority
imately2cminlength,andextendsfromthebaseoftheprostate, ofmen,therightseminalvesicleisslightlylargerthantheleft;thesize
betweenthemedianandlaterallobes,towardsitsopeningontheveru- ofbothglandsdecreaseswithage.
montanum(seeFig.75.13).Theductsdiminishinsizeandconverge Inessence,eachseminalvesicleisacoiledtubewithirregulardiver-
towardstheirends.Ejaculatoryductobstruction,thoughrare,canlead ticula,containedwithinadense,fibromuscularsheathandpartly
tooligospermiaorazoospermia.Causesincludecongenitalcysts,such coveredbyperitoneum.Theupperpoleisacul-de-sac,whilethelower
asMüllerianductcysts,oriatrogenicinjuryduringurethralmanipula- polenarrowstoastraightduct,which,togetherwiththevasdeferens,
tion.Incontrasttothewallsofthevasdeferens,thewallsoftheejacula- culminatesastheejaculatoryduct.Theseminalvesiclesareintimately
toryductsarethin.Theyconsistofanouterfibrouslayer,which associatedwiththeprostateandbladderanteriorly,thedistalureter
decreasesinthicknessontheirentryintotheprostate;athinlayerof superiorly,andtherectumandDenonvilliers’fasciaposteriorly.The
smoothmusclefibres;andamucosalinedbycolumnarepithelium.The ampullaeofthevasdeferensliealongthemedialmarginsofthe
ductsdilateduringejaculation.Normalluminalandwalldimensions seminalvesicles,whiletheveinsoftheprostaticvenousplexuslie
oftheejaculatoryductareremarkablyuniformamongmen;aluminal laterally. | 1,769 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
MAlE REPRoduCTiVE sysTEM
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Rectum Bladder Left seminal vesicle
Fig. 76.18 The microstructure of the seminal vesicles, showing the
tubulo-acinar structure.
locatedlateraltothemembranousurethraandsuperiortotheperineal
membrane.Theyaredrainedbylongexcretoryducts,eachductbeing
almost3cminlength,whichpassobliquelyandanteriorlyfromthe
regionofthemembranousurethra,topenetratetheperinealmem-
brane,andopenonthefloorofthebulbarurethra,approximately
2.5cmbelowtheperinealmembrane.Theglandsaresurroundedby
fibresoftheurinarysphincter.Duringsexualexcitement,contractionof
Obturator internus
themusclefibresleadstoexpulsionofclearmucusfromtheglandsinto
Fig. 76.17 An axial magnetic resonance imaging (MRI) scan
thebulbarurethra.Secretionsofthebulbourethralglandscomprise
demonstrating the normal high signal in the seminal vesicles on a
5–10%ofthetotalejaculatevolume.
T2-weighted scan.
Microstructure
Agenesisoftheseminalvesiclesisacongenitalanomaly,whichis
Eachbulbourethralglandconsistsofseverallobulesenclosedbya
associatedwithabsenceofthevasdeferensorvasoureteralcommunica-
fibrouscapsule.Thesecretoryunitsaretubulo-alveolarinform.The
tion(Wuetal2005).
glandularepitheliumiscolumnar,andsecretesacidicandneutral
mucinsintotheurethrapriortoejaculation;thesecretionsprimarily
Vascular supply and lymphatic drainage havealubricatingfunction.Diffusemucosa-associatedlymphoidtissue
(MALT)isassociatedwiththeglands.
Theprimarybloodsupplytotheseminalvesiclesisfromthevesiculo-
deferentialartery,abranchoftheumbilicalartery(Braithwaite1952). PERIURETHRAL GLANDS
Anadditionalsourceofbloodsupplyistheinferiorvesicalartery,which
arisesfromtheinternaliliacarteryortheinferiorglutealartery.Venous
Theperiurethralglands(glandsofLittre)aremostnumerousinthe
drainageisprovidedbythevesiculodeferentialveinsandtheinferior
penileurethra.Likethebulbourethralglands,theysecretemucusinto
vesicalplexus.Lymphaticdrainage,accordingly,occursviatheinternal
thelumenoftheurethrapriortoejaculation;thesecretionshavea
iliacnodes.
lubricatingfunction.
Innervation
EXTERNAL GENITALIA
Theseminalvesiclesreceivepreganglionicparasympatheticinputfrom
thepelvicnerve,andsympathetic(postganglionic)andparasympa- PENIS
thetic(preganglionic)inputfromthehypogastricnerve.
Thepenisconsistsofanattachedrootintheperineum(radix),anda
Microstructure
free,pendulousbody(shaft),whichiscompletelyenvelopedinskin
(Fig. 76.19).Atitsbase,thepenisissupportedbytwosuspensoryliga-
Afterpuberty,thevesiclesmatureintoelongated,sac-likestructures, ments,whichanchorittothepubicsymphysis(Fig. 76.20B).These
produceaviscouswhite–yellowfluidthatcontributestoatleasttwo- ligamentsarecomposedprimarilyofelasticfibresandarecontinuous
thirdsofthetotalejaculatevolume,andplayanimportantroleinsperm withBuck’sfasciaofthepenis.Thepenileshaftcontainsthreeerectile
motilityandmetabolism.Thesecretedfluidisrichinfructose,coagula- columns–thepairedcorporacavernosaandthecorpusspongiosum;
tionproteinsandprostaglandins,withapHintheneutraltoalkaline theurethra;andtheinvestingfasciae,bloodvesselsandnervesassoci-
range.Thewalloftheseminalvesicleiscomposedofanexternalcon- atedwiththesestructures(Fig. 76.20A).
nectivetissuelayer,amiddlesmoothmusclelayer(significantlythinner Thecorporacavernosalieinintimateappositionwithoneanother
thanthecorrespondinglayerinthevasdeferens),andaninnermucosal alongthelengthofthepenileshaft(Fig. 76.21);thecorpusspongiosum
layerwithahighlyfolded,labyrinthinestructure(Fig. 76.18).The liesintheventralgroovebetweenthecavernousbodies.Proximally,
mucosallayerislinedbycuboidaltopseudostratifiedcolumnarepithe- posteriortothesuspensoryligaments,therightandleftcorporacaver-
lium,featuringtypicalprotein-secretingcells.Contrarytotheimplica- nosadivergetoformtwotaperingprocesses,thecrurapenis,whichare
tionoftheirname,seminalvesiclesarenotreservoirsforspermatozoa, firmlyanchoredtotheischiopubicrami(seeFig.76.20B).Thecorpus
exceptincasesofejaculatoryductobstruction;theycontractduring spongiosumbroadensbetweenthetwocruratoformthebulbospongi-
ejaculationtoreleasesecretionsintotheejaculatoryduct. osusmuscle(seeFig.76.20C).Atthedistalendofthepenis,thecorpus
spongiosumagainenlargesandassumesabulbousshapetoformthe
glanspenis.Theroundedbaseoftheglans,thecorona,separatesthe
BULBOURETHRAL GLANDS glansfromthepenileshaft.Theglansiscoveredbytheforeskin
(prepuce),whichisaloosefoldofretractableskinattachedtothe
Thebulbourethralglands(Cowper’sglands)aresmall,round,yellow, ventralsurfaceoftheglanspenis,underthecorona,atthefrenulum.
lobulatedstructures,measuringapproximately1cmindiameter,and Cutaneoussensitivityisgreatestovertheglanspenis. | 1,770 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
External genitalia
1281
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RETPAHC
A C
Body of penis
Glans penis
Neck of glans
Testis Corona of glans
Prepuce
Epididymis, Glans penis
vas deferens,
vessels,
nerves and
lymphatics
Position of
perineal body
Ischial tuberosity
Body of penis (unattached parts
of corpus spongiosum and
B
D Crus of penis (attached part corpora cavernosa)
of corpus cavernosum) Glans penis
Glans penis
Frenulum
Ventral surface
of body of penis
Raphe
Testis
Bulb of penis (attached part
of corpus spongiosum) Position of perineal body
Fig. 76.19 Structures in the male urogenital triangle. A, An inferior view. B, The ventral surface of the body of the penis. C, A lateral view of the body of
the penis and glans. D, An inferior view of the urogenital triangle of a male, with the erectile tissues of the penis indicated with overlays. (With permission
from Drake RL, Vogl AW, Mitchell A (eds), Gray’s Anatomy for Students, 2nd ed, Elsevier, Churchill Livingstone. Copyright 2010.)
Skin Theskinofthepenileshaftisthin,highlyelasticanddevoidof Shaft Themajorportionofthepenileshaftconsistsofthepaired
appendages(hairorglandularelements),withtheexceptionofsmegma- corporacavernosa.Thesecontainerectiletissue,enclosedwithina
producingglandslocatedatthebaseofthecorona.Itisalsodevoidof densefibroelasticsheathofconnectivetissue,thetunicaalbuginea
fatandquitemobilebecauseoflooseattachmentsbetweenthedartos (seeFigs76.21E,76.22).Theouterlongitudinalandinnercircular
fasciaandtheunderlyingBuck’sfascia.Incontrast,theskinoftheglans fibresofthetunicaformanundulatingmeshworkwhenthepenisis
isimmobile,asaresultofitsdirectattachmenttotheunderlyingtunica flaccidbutbecometightlystretchedonerection.Thecircularfibres
albuginea.Bloodsupplytothepenileskinisindependentoftheerectile surroundeachcorpusseparatelyandthecorporaarethensurrounded
bodies,andisderivedfromtheexternalpudendalbranchesofthe asaunitbytheouterlongitudinalfibres.Smoothmusclebundles
femoralvesselsthatenterthebaseofthepenisandrunlongitudinally traverse the erectile bodies to form endothelium-lined cavernous
withinthedartosfascia,formingarichanastomoticnetwork.Thus,it sinuses,whichgivetheerectiletissueaspongyappearanceongross
ispossibletomobilizepenileshaftskinonavascularpedicleforsurgi- examination.Bloodflowintothesinusesleadstopenileengorgement
calproceduressuchasurethralreconstruction. andcompressionofvenousoutflowchannels,resultinginpenile
Thesuperficialpenilefasciaisdevoidoffat,andconsistsofloose erection.
connectivetissueinterspersedbyfibresofthedartosmusclefromthe Thecorporacavernosaarenotdistinct,separatestructuresbutare
scrotum;itiscommonlyreferredtoasthedartoslayer.Incontrast,the dividedinthemidlinebyafibrousseptumthatiscontinuouswith
deeppenilefasciaisadenserfascialsheath,knownasBuck’sfascia, thedeepcircularfibresofthetunicaalbuginea.Theseptumiscom-
whichenvelopsbothcorporacavernosaandsplitstoenvelopthecorpus pleteandthickproximally,butincompletedistally,permittingcom-
spongiosum(Fig. 76.22B).Distally,itblendswiththetunicaalbuginea municationandexchangeofbloodflowbetweenthecorporalbodies.
coveringallthreecorporalbodies.Proximally,itiscontinuouswiththe Thewidemediangroovealongtheventralaspectofthecorporacaver-
dartosmuscleandthedeepperinealfascia.Bleedingfromatearinthe nosaisoccupiedbythecorpusspongiosum,containingtheurethra.
corporalbodiesisusuallycontainedwithinBuck’sfascia,andecchymo- Dorsally,asimilar,butnarrower,groovecontainsthedorsalneurovas-
sisislimitedtothepenileshaft. cularbundle.Thecorporacavernosaenddistallywithintheglans
penisasindividual,roundedcones(seeFig.76.19D).Thecorpus
Root Theroot(radix)ofthepenisconsistsofthreemassesoferectile spongiosumcontainslesserectiletissuethanthecorporacavernosa,
tissueintheurogenitaltriangle:namely,thetwocruraandthebulb, andisenclosedbyathinnerlayeroftunicaalbuginea.Theurethra
firmlyattachedtothepubicarchandtheperinealmembrane,respec- traversesthelengthofthecorpusspongiosum,terminatingataslit-
tively.Thecruraaretheposteriorextensionsofthecorporacavernosa, likemeatusonthetipoftheglanspenis,whichis,itself,anexpan-
whilethebulbisthedilatedposteriorendofthecorpusspongiosum. sionofthecorpusspongiosum.Numeroussmallpreputialglands
Theurethraentersthebulbviaitsposteriorsurfaceandtravelsthe secretingsebaceoussmegmalinethecoronaalongthebaseofthe
lengthofthepenileshaftwithinthecorpusspongiosum. glanspenis. | 1,771 | 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 Corpora cavernosa
Body of penis
Corpus spongiosum (cross-section)
containing urethra
Glans penis
Corpus cavernosum
External urethral
meatus (orifice)
Navicular fossa of urethra
Perineal membrane
Corpus spongiosum Crus of penis (attached part of
corpus cavernosum)
Bulbourethral gland
within deep pouch
B Fundiform ligament of penis
Suspensory ligament of penis
Ischiocavernosus
Midline raphe
Bulbospongiosus
Puborectalis
Superficial anal sphincter
Superficial transverse perineal muscle
C Penile skin
Superficial penile (Colles’) muscle
Ischiocavernosus Tunica albuginea
Deep penile (Buck’s) fascia
Glans penis
Corpus spongiosum
Corpus cavernosum
Bulbospongiosus Urethra
Fig. 76.20 A, The erectile tissues of the penis. B, The muscles in the superficial perineal pouch. C, The muscles and erectile tissues of the penis in
section. (A–B, With permission from Drake RL, Vogl AW, Mitchell A (eds), Gray’s Anatomy for Students, 2nd ed, Elsevier, Churchill Livingstone. Copyright
2010. C, Adapted from Drake RL, Vogl AW, Mitchell A, Tibbitts R, Richardson P (eds), Gray’s Atlas of Anatomy, Elsevier, Churchill Livingstone. Copyright
2008.) | 1,772 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
External genitalia
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RETPAHC
Corpus Corpus Prostate Seminal
cavernosum spongiosum vesicle Bladder
A B
Penile Bulbospongiosus Prostatic urethra Corpus cavernosum Corpus spongiosum
urethra
Crus of the corpus cavernosum Corpus cavernosum Tunica albuginea Corpus cavernosum Corpus spongiosum Glans penis
C D E
Bulb of penis Prostate Anal canal Tunica Corpus
albuginea cavernosum
Fig. 76.21 A–B, An MRI scan of the penis showing the corpora cavernosum and spongiosum. Note the corpus spongiosum flaring posteriorly into
the bulbospongiosus. C, An MRI scan showing the bulb of the penis and the attachment of the posterior portion of the corpora cavernosa, the crura.
D–E, An MRI scan of the penis showing the tunica albuginea.
Vascular supply and lymphatic drainage entialbranchestothecorpusspongiosumandurethra.Therichblood
supplytothespongiosumallowssafedivisionoftheurethraduring
stricturerepair.
Arteries
Bloodsupplytothecorporalbodiesisderivedfromtheinternalpuden-
Cavernous (deep, cavernosal) artery of the penis Thecavern-
dalartery,abranchoftheinternaliliacartery,whichtravelswithin
ous(deep,cavernosal)arteryofthepenisisusuallyapairedvesselthat
Alcock’scanalbeforereachingthepenisandperineum(Fig. 76.23).As
piercesthetunicaalbugineaofthecorporacavernosaatthehilumof
itemergesfromAlcock’scanal,theinternalpudendalarterygivesoff
thepenisandthentravelsnearthecentreofthecorporalbodiesinthe
theperinealartery,tosupplyischiocavernosusandbulbospongiosus,
directionoftheglanspenis.Alongitscourse,itgivesoffseveralstraight
andtheposteriorsurfaceofthescrotum,aswellasthecommonpenile
andhelicinebranchesatregularintervals;theyopendirectlyintothe
arterythatsuppliesthedeepstructuresofthepenis(Fig. 76.24).
sinusoidalspacesofthecorporalbodies.
Thecommonpenilearteryhasthreemainbranches:thebulboure-
Variationsinpenilevascularanatomyarecommon,andmayinclude
thralartery,thedorsalpenilearteryandthecavernous(deep,cavern-
asingleorabsentcavernousarteryorthepresenceofaccessorypuden-
osal)artery(Fig. 76.25).
dalarteries(Bareetal1994,Matin2006).Whilepenilearterialsupply
iscommonlyderivedfrombothaccessoryandinternalpudendalarter-
Bulbourethral artery Thebulbourethralarterypenetratestheperi-
ies,itmaybederivedexclusivelyfromeithertheinternalpudendal
nealmembranetoenterthespongiosumfromaboveitsposterolateral
arteriesortheaccessorypudendalarteries(Droupyetal1997).Recog-
borderandsuppliesthepenilebulbandtheurethra,inadditiontothe
nizingsuchvariationisextremelyimportantforanysurgeoncontem-
corpusspongiosumandglanspenis.
platingpenilerevascularizationsurgery.
Dorsal artery of the penis Thedorsalarteryofthepenispasses
Veins
betweenthecruspenisandthepubistoreachthedorsalsurfaceofthe
corporalbodies.Itrunsalongsidethedorsalveinandthedorsalpenile Bloodleavingthepenisisdrainedbyoneofthreevenoussystems:
nerve,andisattached,togetherwiththesestructures,totheunderside superficial,intermediateordeep(seeFigs76.22B,76.23).Thesuperfi-
ofBuck’sfascia.Asitcoursestotheglanspenis,itgivesoffcircumfer- cialveinsarecontainedwithinthedartosfasciaonthedorsolateral | 1,773 | 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 vein Fig. 76.22 A, Layers of the penis and main structures.
B, C, Cross-sectional anatomy of the penile shaft.
Glans
Corpus spongiosum
surrounding urethra External urethral
meatus (orifice)
B
Superficial dorsal vein
Deep dorsal vein
Dorsal artery
Dorsal nerve
Cavernous vein
Tunica albuginea
Cavernous artery Superficial penile
(Colles’) fascia
Septum of penis
Deep penile
(Buck's) fascia
Circumflex vein
Corpus spongiosum
with urethra Sinusoidal spaces
C
Deep dorsal vein Superficial dorsal vein
Dorsal artery
Superficial dorsal artery
Dorsal nerve
Efferent vein
Corpus cavernosum
Cavernous vein
Skin
Emissary vein
Superficial penile
(Colles') fascia
Outer circular layer
Tunica albuginea Areolar tissue
Inner longitudinal layer
Deep penile
Cavernous artery (Buck's) fascia
Helicine artery
Septum of penis
Sinusoid
Bulbourethral vein
Urethral artery
Corpus spongiosum
Urethra
surfaceofthepenis.Theyreceivebloodfromthepenileshaftskinand groovebetweenthetwocorporacavernosa.Itpassesinferiortothe
prepuce,andcoalesceatthebaseofthepenistoformasinglesuperficial pubicsymphysisatthelevelofthesuspensoryligament,leavingthe
dorsalveinthatdrainsintothegreatsaphenousveinviathesuperficial shaftofthepenisatthecrus,anddrainsintotheprostaticplexus.
externalpudendalveins. Deepvenousdrainageoccursviathecruralandcavernous(deep,
Theintermediatedrainagesystemcontainsthecircumflexanddeep cavernosal)veins,whichreceivebloodfromtheproximalthirdofthe
dorsalveins,whichliewithinandbeneathBuck’sfascia.Thissystem penis.Theemissaryveinsconsolidateinto2–5veinsonthedorsome-
receivesbloodfromtheglans,corpusspongiosumandthedistaltwo- dialsurfaceofthecorporacavernosa.Cruralveinsariseinthemidline,
thirdsofthepenis.Circumflexveinsoriginateinthecorpusspongio- inthespacebetweenthecrura,andjointhecavernousveinsatthe
sum,andcoursearoundthecorporacavernosatomeetthedeepdorsal hilumofthepenis,ultimatelydrainingintotheinternalpudendalvein.
veinperpendicularly.Theyareonlypresentinthedistaltwo-thirdsof
Lymphatic drainage
thepenileshaft,andrangebetween3and10innumber.Intermediate
venulesintheerectiletissueofthecorporacavernosaarisefromthe Thepenileandperinealskinisdrainedbylymphaticvesselsthataccom-
cavernoussinusesanddrainintoasubtunicalcapillaryplexus.This panytheexternalpudendalveinstothesuperficialinguinalnodes.
plexusgivesrisetoemissaryveinsthatcourseobliquelythroughthe Lymphaticsfromtheglanspenispasstothedeepinguinalandexternal
tunicaalbuginea,anddraineitherintothecircumflexveins,ordirectly iliacnodes,andthosefromtheerectiletissueandpenileurethrapass
intothedeepdorsalvein.Thedeepdorsalveinliesinthemidline totheinternaliliacnodes. | 1,774 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
External genitalia
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External iliac artery and vein nervesandhelicinearteriesareintimatelyassociatedwithsmooth
muscle.Thehelicinearteriesarecontractedandtortuousintheflaccid
Internal iliac artery and vein state,andstraightanddilatedintheerectstate.
Thetunicaalbugineasurroundingthecorporaconsistsofaninner
Internal pudendal circularandouterlongitudinallayerofelasticfibresarrangedinalat-
artery and vein ticednetwork.Venousdrainagefromthecorporacavernosaoriginates
inthetrabeculaebetweentheperipheralsinusoidsandthetunicaalbug-
inea(thesubtunicalvenousplexus)beforeexitingthecorporaviathe
emissaryveins.
Emissaryveinstravelbetweenthetwolayersofthetunicaalbug-
inea,andexittheouterlayerinanobliquefashion.Theouterlayer
compressestheemissaryveinswhenthepenisbecomesengorged
withblood,preventingvenousoutflow,andtherebymaintainsthe
erection.
Thestructureofthecorpusspongiosumissimilartothatofthe
corporacavernosa,withtheexceptionoflargersinusoidsandathinner
tunicaalbuginea.Theglanshasnotunicalcovering.
ERECTION AND EJACULATION
Penileerectionisaneurovascularprocess,initiatedbysexualstimula-
tionandrelaxationofthesmoothmuscleofthecorporacavernosaand
mediatedbyvariousneurotransmittersproducedbytheparasympa-
theticnervesandtheendothelium.Themostimportantneurotransmit-
terisnitricoxide,whichactsviathecyclicguanosinemonophosphate
Vesical venous (cGMP)secondmessengersystem.Followingsmoothmusclerelaxa-
plexus
tion,thereisrapidinfluxofbloodflowfromthehelicinearteries,filling
thecavernousspacesandleadingtopeniletumescence.Theresulting
distensioncompressestheemissaryveins,preventingvenousoutflow.
Thisso-called‘veno-occlusivemechanism’convertstumescenceintoan
Cavernous artery
erection.Continuingcutaneousstimulationoftheglansandfrenulum
Dorsal artery and Cf penis
contributessignificantlytowardsmaintaininganerectionandinitiating
vein of penis
orgasmandejaculation.Erection,therefore,dependsonavarietyof
factors,includinganormalpsychogenicresponsetostimulation,intact
Artery of the bulb parasympatheticnerves,healthycorporalsmoothmusclecapableof
of the penis relaxation,patentarteriescapableofdeliveringbloodattherequired
rate,andanormalvenoussystem.Followingejaculation,thesequence
justdescribedisreversed;smoothmusclecontractioninresponseto
Periprostatic
venous plexus sympatheticstimulationleadstopeniledetumescence.
Emissionandejaculationareseparate,butrelated,processes.Emis-
sionisthetransmissionofseminalfluidfromthevasdeferens,prostate
Fig. 76.23 The perineal vessels. (Adapted from Drake RL, Vogl AW,
andseminalvesiclesintotheprostaticurethraandisundersympathetic
Mitchell A (eds), Gray’s Anatomy for Students, 2nd ed, Elsevier, Churchill
control.Ejaculationistheexpulsionofseminalfluidfromtheprostatic
Livingstone. Copyright 2010.)
urethratotheexteriorandhasbothautonomicandsomaticcompo-
nents.Thefirstdiscernibleeventduringejaculationiscontractionof
bulbospongiosus,whichoccursapproximatelysixtimesandisunder
somaticcontrol.Antegradeejaculationrequiresconcomitantbladder
Innervation
neckclosureandperiurethralmusclecontraction(Ch.75).Relaxation
oftheexternalurethralsphincter,underautonomiccontrol,permits
Arichsensoryinnervationtotheglanspenisisprovidedbythedorsal expulsionofseminalfluidfromtheprostatictothebulbarurethra,and
nerve,adivisionofthepudendalnerve;itfollowsthecourseofthe fromtheretotheexterior.Thetimingofthisprocessissuchthatthe
dorsalpenilearteries(Fig. 76.26,seealsoFig.76.2).Smallbranches ejaculateisexpelledfromtheexternalurethralmeatusbetweenthe
fromtheperinealnerveprovideadditionalinnervationtotheskinon secondandfinalcontractionofbulbospongiosus;insomemen,ejacu-
theventrumofthepenis,asfardistallyastheglans(Uchioetal1999). lationmaybepulsatile.
Sympatheticandparasympatheticinputtothecorporacavernosais
providedbythecavernous(deep,cavernosal)nerve,whichoriginates Erectile dysfunction and priapism
inthepelvicplexus.Itcoursesalongtheposterolateralaspectofthe
prostatebeforeexitingthepelvis,togetherwiththeurethra,andenter-
ingthecorporacavernosaatthecrus.Beforeenteringthecavernous Available with the Gray’s Anatomy e-book
bodies,thecavernousnervesendsbranchestothecorpusspongiosum.
Parasympatheticinputtothepenis(excitatory)originatesintheneu-
ronesofthefirstfoursacralsegmentsofthespinalcordandtravelsvia SCROTUM
thepelvicsplanchnicnerves(nervierigentes)tothepelvicplexus(see
Fig.76.26),wherepreganglionicfibressynapseonpostganglionic
Thescrotumiscomposedofmultiplelayersoftissues,includingskin,
neuronsthatgiverisetothecavernousnerve.Sympatheticinputtothe
dartosmuscleandexternalspermatic,cremastericandinternalsperm-
penis(inhibitory)originatesintheintermediolateralcolumnsofthe
aticfasciae(seeFig.76.3).Theinternalspermaticfasciaisloosely
eleventhandtwelfththoracic,andfirstlumbarsegmentsofthespinal
attachedtotheparietallayerofthetunicavaginalis.
cord,andtravelsthroughthesympathetictrunkbeforedescendingto
Scrotalskinisthin,pigmented,devoidoffat,hair-bearing,andrich
thepelvicplexus.Parasympatheticstimulationproducesvasodilation,
insebaceousandsweatglands.Itisalsorichlyinnervatedbysensory
whilesympatheticinnervationcausesvasoconstriction,contractionof
nervesthatrespondtostimulationoftheskinandhairs,andtochanges
theseminalvesiclesandprostate,andseminalemission.
intemperature.Theappearanceofthescrotalskinmayvaryfrom
smoothtorugated,dependingonthedegreeofcontractionofthe
Microstructure
underlyingdartosmuscle.Amidlinerapheextendsfromtheurethral
meatus,downtheventralpenileshaftandtotheanus,signifyingthe
Thecorporacavernosaarecylindersofspongyerectiletissue,composed lineoffusionofthegenitaltubercles(seeFig.72.20).Itisarelatively
ofinterconnectedendothelium-linedsinusoids,separatedbysmooth avascularplaneand,therefore,apopularlocationforincisionsusedto
muscletrabeculae,andsurroundedbyelasticfibres,collagenandloose accessbothscrotalcompartments.Deeptotheraphe,thescrotumis
areolartissue.Thesinusoidsarelargerinthecentre.Terminalcavernous separatedintotwocompartmentsbyaseptumcomposedofallthe | 1,775 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
Male reproductive system
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Erectiledysfunctionistheinabilitytoachievetumescencedespiteade-
quatesexualstimulation.Thepathophysiologyoferectiledysfunction
iscomplex,andinvolvesvascular,neurogenicandpsychogeniccompo-
nents.Commonaetiologiesunderlyingadiagnosisoferectiledysfunc-
tioninclude:inabilitytorelaxthecavernoussmoothmuscle;arterial
insufficiencyduetoatheromatousdisease;neurogenicdysfunctiondue
todiabetesorsurgery;andradiationtherapy.
Aprolongederectionthatfailstosubsideafterejaculationiscalled
priapism.Priapismcan,broadly,beclassifiedasbeinghigh-flow(non-
ischaemic)orlow-flow(ischaemic).Low-flowpriapism,whichisdue
toimpairedeffluxofvenousbloodfromthepenis,ischaracterizedby
significantpainandisamedicalemergency.Ifuntreated,priapismleads
toischaemiaofthecorporalsmoothmuscleandirreversibleerectile
dysfunction.Theaetiologyoflow-flowpriapismincludesconditions
suchassickle-celldiseaseandleukaemia,andtheuseofintracavernosal
injectiontherapywithmedicationssuchasprostaglandin.Incontrast,
high-flowpriapismistheconsequenceofexcessivebloodflowintothe
penis,usuallysecondarytoafistulabetweenthecavernousarteriesand
sinusoidalspaces. | 1,776 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
MAlE REPRoduCTiVE sysTEM
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Fig. 76.24 The blood vessels
and nerves of the perineal
Perineal artery, posterior scrotal branches
region and external genitalia
in the adult male. The fat
body of the ischio-anal fossa
Bulbospongiosus has been removed and
Posterior scrotal nerves
gluteus maximus has been
incised in order to expose the
Dorsal artery of penis Ischiocavernosus course of the pudendal nerve
and internal pudendal artery.
(With permission from
Artery of bulb of penis
Superficial external Waschke J, Paulsen F (eds),
anal sphincter Sobotta Atlas of Human
Dorsal nerve of penis Anatomy, 15th ed, Elsevier,
Perineal artery Urban and Fischer. Copyright
2013.)
Perineal branches, posterior
cutaneous nerve of thigh
Superficial transverse
perineal muscle
Perineal nerve
Posterior cutaneous
nerve of thigh
Dorsal nerve of penis
Dorsal nerve of penis
Inferior rectal nerves
Internal pudendal
Perineal nerve artery and vein
Sacrospinous ligament
Pudendal nerve Inferior rectal artery
Internal pudendal artery
Posterior cutaneous nerve of thigh
Sacrotuberous ligament
Gluteus maximus Levator ani
Anococcygeal ligament Anococcygeal nerves
Dorsal arteries Perineal arteries layersofthescrotalwallexcepttheskin.Thetestesaresuspendedby
thespermaticcordswithinthesecompartments.
ThedartoslayerofsmoothmusclesiscontinuouswithColles’,
Scarpa’sandthedartosfasciaofthepenis.Theexternalspermatic,cre-
mastericandinternalspermaticlayersofthescrotumarecontinuous
withthecorrespondinglayersinthespermaticcord,andarisefromthe
aponeurosesofexternalobliqueandinternalobliqueandthetransver-
salisfasciaoftheabdominalwall,respectively.Thetestisisalsofixed
tothescrotalwallatitslowerpolebyafibrousbandoftissueknown
asthegubernaculum.
Cavernous artery
Bulbourethral artery Developmental anomalies of the scrotum Congenitalagenesis
ofthescrotumisaveryrareanomalycharacterizedbytheabsenceof
thescrotum;norugaearenotedintheperineum(Yilmazetal2013).
Penoscrotaltransposition,inwhichthescrotumislocatedsuperiorand
Circumflex artery anteriortothepenis,isaconsequenceofabnormalgenitaltubercle
developmentandisassociatedwithhypospadias,renalagenesisand
dysplasia,andimperforateanus.
Vascular supply and lymphatic drainage
Arterialsupplytothescrotumincludesexternalpudendalbranchesof
thefemoralartery,scrotalbranchesoftheinternalpudendalartery,and
Fig. 76.25 The arterial blood supply to the body of the penis. acremastericbranchfromtheinferiorepigastricartery.Ofnote,the
anteriorscrotalwallissuppliedprimarilybybranchesoftheexternal
pudendalartery,whichrunparalleltotherugaeanddonotcrossthe
raphe;thisanatomicaldetailisimportantforplanningappropriate
incisionsduringscrotalsurgery.
Thescrotalvesselsarearrangedinadensesubcutaneousnetwork,
whichfacilitatesheatlossandregulationofscrotaltemperature.Venous
drainagefollowsthearterialnetwork,andsimplearteriovenousanas-
tomosesarecommon. | 1,777 | 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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RETPAHC
Key references
Scrotallymphaticsdonotcrossthemedianraphe.Therefore,lym-
phaticdrainagefromthescrotumisalwaysroutedtotheipsilateral
superficialinguinalnodes.
Innervation
Pelvic
Thescrotumisinnervatedbytheilioinguinalnerve,thegenitalbranch
parasympathetic
roots ofthegenitofemoralnerve,twoposteriorscrotalbranchesoftheperi-
nealnerve,andtheperinealbranchoftheposteriorfemoralcutaneous
nerve(seeFig.76.24).Innervationoftheanteriorthirdofthescrotum
isprimarilyderivedfromthefirstlumbarspinalsegment,bywayofthe
ilioinguinalandgenitofemoralnerves(seeFig.76.2).Innervationofthe
posteriortwo-thirdsofthescrotumisprimarilyderivedfromthethird
sacralspinalsegment,viatheperinealandposteriorfemoralcutaneous
nerves.Inordertoanaesthetizethescrotum,spinalanesthesiamust,
therefore,beinjectedhigherthantheL1level.
Obturator
nerve
Bonus e-book images and table
Hypogastric
nerves
Fig. 76.1 A, Reference curves for mean testicular volume measured
by ultrasound. B, Enlargement of the reference curves for mean
Rectum
testicular volume measured by ultrasound.
Prostate
Left inferior Fig. 76.12 Gangrene of the appendix testis secondary to torsion in
hypogastric an 8-year-old child.
Dorsal sensory plexus
nerve Table 76.1 Volume of the left and right testis, as measured by
Pudendal nerve ultrasound in boys between infancy and adolescence.
Cavernous nerves
Posterior scrotal nerve
Fig. 76.26 The nerve supply to the penis. The corpus cavernosum of
penis receives both a parasympathetic and a sympathetic innervation
from the cavernous nerves. It should be noted that, in life, multiple
cavernous nerves emanate from the prostatic plexus and intertwine with
both dorsal sensory nerves. The afferent fibres from the glans pass via
the dorsal nerves of the penis and via the pudendal nerve. (Adapted from
Drake RL, Vogl AW, Mitchell A (eds), Gray’s Anatomy for Students,
2nd ed, Elsevier, Churchill Livingstone. Copyright 2010.)
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men with varicoceles. astudyofcadavericandsurgicalspecimens.JUrol155:1639–42.
BraithwaiteJL1952Thearterialsupplyofthemaleurinarybladder.BrJ Gross and microscopic evaluation of the human ejaculatory duct, correlating
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A definitve and unparallelled summary of the indications and operative abnormal testicular size and various underlying medical disorders.
techniques for operations involving the male reproductive tract. SilberSJ1989Roleofepididymisinspermmaturation.Urology33:
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RETPAHC
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anastomoses with the testicular blood supply, and clinical implications in reportofarareentity.JPediatrUrol991:e76–7.
disease settings. YuasaJ,ItoH,ToyamaYetal2001Postnataldevelopmentofthetestisin
MatinSF2006Recognitionandpreservationofaccessorypudendalarteries Japanesechildrenbasedonobservationsofundescendedtestes.IntJ
duringlaparoscopicradicalprostatectomy.Urology67:1012–15. Urol8:490–4.
MendezJA,EmeryJL1979Theseminiferoustubulesofthetestisbefore,
aroundandafterbirth.JAnat128:601–7. | 1,779 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
CHAPTER
77
Female reproductive system
The female reproductive system consists of the lower genital tract (vulva mons becomes prominent with coarse hair and atrophies slightly after
and vagina) and the upper tract (uterus and cervix with associated menopause.
uterine (Fallopian) tubes and ovaries).
Labia majora
LOWER GENITAL TRACT
The labia majora are two prominent, longitudinal folds of skin that
extend back from the mons pubis to the perineum (Fig. 77.1B). They
VULVA
form the lateral boundaries of the vulva. Each labium has an external,
pigmented surface covered with hairs and a smooth, pink internal
The female external genitalia or vulva include the mons pubis, labia surface with large sebaceous follicles. Between these surfaces there is
majora, labia minora, clitoris, vestibule, vestibular bulb and the greater loose connective and adipose tissue, intermixed with smooth muscle
vestibular glands (Fig. 77.1). (resembling the scrotal dartos muscle), vessels, nerves and glands. The
subcutaneous layer consists of a superficial fatty layer similar to Camp-
Mons pubis
er’s fascia, and a deep membranous layer – Colles’ fascia – continuous
with Scarpa’s fascia of the anterior abdominal wall (p. 1069). The
The mons pubis is the rounded, hair-bearing area of skin and adipose uterine round ligament may end in the adipose tissue and skin in the
tissue over the pubic symphysis and adjacent pubic bone. Before anterior part of the labium. A patent processus vaginalis may also reach
puberty, the mons pubis is relatively flat and hairless, and the labia a labium. The labia join anteriorly to form the anterior commissure.
minora are poorly formed. Through adolescence and into adult life, the Posteriorly, they do not join, but instead merge into neighbouring skin,
A B Skin overlying
body of clitoris
Prepuce of clitoris
Glans clitoris
Frenulum Lateral fold Glans clitoris
Urethral opening Medial fold
Vestibule Opening of duct of Labium minus
(between labia minora) para-urethral gland
Hymen Vestibule
Labium minus
Vaginal opening
Opening of duct of Labium majus
greater vestibular gland
Fourchette
Posterior
commissure
(overlies
perineal body)
C D
Prepuce
of clitoris
Frenulum
Glans clitoris of clitoris Area of opening of the
duct of the para-urethral
gland
Labium
minus
Area of opening of the
External duct of the greater
urethral orifice vestibular gland
Vaginal opening
(introitus)
Fig. 77.1 A, The superficial features of the perineum. B, The labia majora and surrounding external genitalia. C, The labia minora. D, An inferior view of
the vestibule with the left labium minus pulled to one side to show the regions of the vestibule into which the greater vestibular and para-urethral glands
open. (A, With permission from Drake RL, Vogl AW, Mitchell A, Tibbitts R, Richardson P (eds), Gray’s Atlas of Anatomy, Elsevier, Churchill Livingstone.
Copyright 2008. B–D, With permission from Drake RL, Vogl AW, Mitchell A (eds), Gray’s Anatomy for Students, 2nd ed, Elsevier, Churchill Livingstone.
1288 Copyright 2010.) | 1,780 | 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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ending near and almost parallel to each other. The connecting skin A
between them posteriorly forms a ridge, the posterior commissure, Ischiocavernosus Suspensory ligament
which overlies the perineal body and is the posterior limit of the vulva.
The distance between the posterior vulva and the anus is 2.5–3 cm and
is termed the ‘gynaecological’ perineum.
Labia minora
The labia minora are two small cutaneous folds, devoid of fat, that lie
between the labia majora. They extend from the clitoris obliquely
down, laterally and back, flanking the vaginal orifice. Anteriorly, each
labium minus bifurcates. The upper layer of each side passes above the
clitoris to form the hood or prepuce, while the lower layer passes below
the clitoris to form the frenulum of the clitoris (Fig. 77.1A–C). Seba-
ceous follicles are numerous on the medial surfaces. Sometimes, an
extra labial fold (labium tertium) is found on one or both sides between Bulbospongiosus Perineal body Superficial transverse perineal muscle
the labia minora and majora. Adhesions between the labia minora are
common in prepubertal girls and may predispose to urinary infections
(Leung and Robson 1992).
B
Vestibule Glans clitoris Skin Body of clitoris
(cross-section)
Corpus cavernosum
Corpora cavernosa
The vestibule is the cavity that lies between the labia minora. It contains
the vaginal and external urethral orifices and the openings of the two
greater vestibular (Bartholin’s) glands and of numerous mucous, lesser
vestibular glands. There is a shallow vestibular fossa between the vaginal
orifice and the frenulum of the labia minora. The posterior part of the
vestibule is a classic site where a fistulous opening of the rectum may
be located in girls born with an imperforate anus (Bill et al 1975).
Urethra
The urethra opens into the vestibule about 2.5 cm below the clitoris
and above the vaginal opening via a short, sagittal cleft with slightly
raised margins: the urethral meatus. The meatus is very distensible and
varies in shape; the aperture may be rounded, slit-like, crescentic or Bulb of vestibule Greater vestibular gland Crus of clitoris
in superficial pouch (attached part of
stellate. The ducts of the para-urethral glands (Skene’s glands) open on
corpus cavernosum)
each side of the lateral margins of the urethra.
C
Bulbs of the vestibule
Body of clitoris (unattached
The bulbs of the vestibule lie on each side of the vestibule (Fig. 77.2B). parts of corpora cavernosa)
They are two elongated masses of erectile tissue, 3 cm long, which flank Mons pubis
the vaginal orifice and unite anterior to it by a narrow commissura
bulborum (pars intermedia). Their posterior ends are expanded and are
in contact with the greater vestibular glands. Their anterior ends taper
and are joined by a commissure, and also to the clitoris by two slender
bands of erectile tissue. Their deep surfaces contact the inferior aspect
of the perineal membrane; superficially, each is covered posteriorly by
bulbospongiosus (Fig. 77.2A) (Delancey 2011).
Greater vestibular glands
(Bartholin’s glands)
The greater vestibular glands are homologues of the male bulbourethral
glands. They consist of two small, round or oval, reddish-yellow bodies
that flank the vaginal orifice, in contact with, and often overlapped by,
the posterior end of the vestibular bulb. Each opens into the vestibule
by a 2 cm duct, situated in the groove between the hymen and the
labium minus at approximately the 5 and 7 o’clock positions (Corton
Crus clitoris (attached part
2012) (see Fig. 77.1D). The glands are composed of tubulo-acinar of corpus cavernosum) Glans clitoris
tissue; the secretory cells are columnar and secrete a clear or whitish
Fig. 77.2 A, The muscles of the vestibule and clitoris. B, The erectile
mucus for lubrication during sexual arousal.
tissues of the clitoris. C, The erectile tissues of the clitoris, vestibule and
Clitoris greater vestibular gland with a surface anatomy overlay. (A–B, Adapted
with permission from Drake RL, Vogl AW, Mitchell A (eds), Gray’s
Anatomy for Students, 2nd ed, Elsevier, Churchill Livingstone. Copyright
The clitoris is an erectile structure, partially enclosed by the anterior 2010. C, With permission from Drake RL, Vogl AW, Mitchell A (eds),
bifurcated ends of the labia minora. It has a root, a body and a glans Gray’s Anatomy for Students, 2nd ed, Elsevier, Churchill Livingstone.
(see Fig. 77.2). The body can be palpated through the skin. It contains Copyright 2010.)
two corpora cavernosa, composed of erectile tissue and enclosed in
dense fibrous tissue, and separated medially by an incomplete fibrous
pectiniform septum. The fibrous tissue forms a suspensory ligament Vascular supply and lymphatic drainage
that is attached superiorly to the pubic symphysis. Each corpus caverno-
of the vulva
sum is attached to its ischiopubic ramus by a crus that extends from
the root of the clitoris. The glans clitoris is a small, round tubercle of
Arteries
spongy erectile tissue at the end of the body, connected to the bulbs of
the vestibule by thin bands of erectile tissue. It is exposed between the The arterial blood supply of the female external genitalia is derived
anterior ends of the labia minora. Its epithelium has high cutaneous from the superficial and deep external pudendal branches of the femoral
sensitivity, important in sexual responses. Congenital absence of the artery superiorly and the internal pudendal artery inferiorly on each
clitoris is very rare. side (Figs 77.3A, 77.4). | 1,781 | 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
Common iliac vein Internal iliac vein
Common iliac artery Median sacral artery
Superior vesical artery and vein
Internal iliac artery
Rectum, longitudinal
Ovarian artery
muscular layer
Umbilical artery, patent part Uterine artery
Ureter
Middle rectal artery
Right ovary and vein
Recto-uterine fold
Uterine tube, infundibulum
Uterine tube Left ureter
Round ligament of uterus
External iliac Uterine artery and
artery and vein vein
Vagina
Uterus
Middle rectal
Urinary bladder
artery and vein
Vaginal artery
Left ovary
Inferior vesical
Uterine artery,
artery
tubal branch
Levator ani
Bulb of vestibule
Inferior rectal vein
Round ligament of
uterus
Vaginal venous plexus
Vesical veins Internal pudendal artery and vein
B
Abdominal aorta Common iliac nodes
Iliolumbar artery
Ovarian artery and vein Superior rectal
artery and vein
Internal iliac node
Rectum
External iliac node
Genitofemoral nerve Uterine artery
and vein
Obturator nerve
Superior rectal
External iliac artery and vein node
Obturator artery and vein Vaginal artery
External iliac nodes, Internal pudendal
medial and lateral nodes artery
Inferior epigastric
artery and vein
Cord of umbilical
artery Recto-uterine
pouch
Round ligament of
uterus
Umbilical artery,
patent part
Levator ani
Round ligament of uterus
Uterus, intestinal surface
Superior vesical arteries
Ureter
Urinary bladder Round ligament of uterus
Median umbilical ligament Uterine tube, isthmus
Fig. 77.3 A, The vessels of the female pelvis: sagittal view. B, The nerves and lymphatics of the female pelvis: sagittal view. (With permission from
Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.) | 1,782 | 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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Bulbospongiosus Fig. 77.4 The muscles,
External urethral orifice
vessels and nerves of
Internal pudendal artery, the female perineum:
Bulb of vestibule posterior labial branches inferior view. (With
Vein of bulb of Ischiocavernosus permission from
vestibule Waschke J, Paulsen F
Dorsal artery of (eds), Sobotta Atlas of
clitoris Human Anatomy, 15th
ed, Elsevier, Urban &
Perineal artery Urogenital diaphragm Fischer. Copyright
2013.)
Dorsal nerve of
clitoris
Superficial transverse
perineal muscle
Perineal branches,
posterior cutaneous
nerve of thigh
Posterior labial nerves
Inferior rectal nerves
Internal pudendal
artery and vein
Posterior cutaneous
Gluteus maximus
nerve of thigh
Inferior rectal artery
Perineal nerves
Pudendal nerves
Levator ani Anococcygeal nerves
External anal sphincter
Anococcygeal ligament
This blood supply to the labial fat must be carefully preserved during
VAGINA
vaginal surgery, e.g. in creating a Martius fat pad flap to repair a vesico-
vaginal fistula where blood supply has already been compromised by
The vagina is a fibromuscular tube lined by non-keratinized stratified
radiation or fibrosis (Delancey 2011).
epithelium. It extends from the vestibule (the opening between the
Veins labia minora) to the uterus. The upper end of the vagina surrounds the
Venous drainage of the vulval skin is via external pudendal veins to the vaginal projection of the uterine cervix. The anular recess between the
long saphenous vein. Venous drainage of the clitoris is via deep dorsal cervix and vagina is the fornix; the different parts of the fornix are given
veins to the internal pudendal vein, and via superficial dorsal veins to separate names, i.e. anterior, posterior and right and left lateral, but they
the external pudendal and long saphenous veins. are continuous (Fig. 77.6).
In the standing position, the vagina ascends posteriorly and superi-
Lymphatic drainage
orly, forming an angle of 60–70° with the horizontal plane (Corton
A meshwork of connecting vessels from the skin of the labia, clitoris 2012). The vagina forms an angle of over 90° to the uterine axis (see
and perineum join to form three or four collecting trunks that drain to Fig. 77.12); this angle varies with the contents of the bladder and
superficial inguinal nodes lying on the cribriform fascia covering the rectum. The apex of the vagina is directed posteriorly towards the ischial
femoral artery and vein; these nodes drain through the cribriform fascia spines. The width of the vagina increases as it ascends. The inner sur-
to the deep inguinal nodes lying medial to the femoral vein (Corton faces of the anterior and posterior vaginal walls are in contact with each
2012). The deep inguinal nodes drain via the femoral canal to the pelvic other, forming a transverse slit. The vaginal mucosa is attached to the
nodes (Table 77.1). The last of the deep inguinal nodes lies under the uterine cervix higher on the posterior cervical wall than on the anterior;
inguinal ligament within the femoral canal and is often called Cloquet’s the anterior wall is approximately 7.5 cm long and the posterior wall
node. Lymph vessels from the clitoris drain directly to the deep inguinal is approximately 9 cm long. The fibromuscular anterior wall of the
nodes, and direct clitoral lymphatics may pass to the internal iliac nodes vagina supports the base of the bladder in its middle and upper por-
(Fig. 77.3B). Lymph vessels in the perineum and lower part of the labia tions, and the urethra (which is embedded in it) inferiorly. The fibro-
majora drain to the rectal lymphatic plexus. muscular posterior wall of the vagina supports the rectum. The upper
quarter of the posterior vagina is separated from the rectum by the
Innervation
peritoneum of the recto-uterine pouch, and by moderately dense fibro-
muscular tissue (Denonvilliers’s fascia) in its middle half (Delancey
The main nerve supply of the vulva is the pudendal nerve (S2, 3 and 2011). In its lower quarter, it is separated from the anal canal by the
4) through its inferior rectal and perineal branches and the dorsal nerve fibromuscular perineal body. The upper part of the vagina is supported
of the clitoris (Table 77.2; Figs 77.4, 77.5). Shoja et al 2013). The laterally by levator ani, together with the transverse cervical, pubocervi-
sensory innervation of the anterior and posterior parts of the labium cal and uterosacral ligaments. Pubovaginalis provides a U-shaped mus-
majus differs. The anterior third of the labium majus is supplied by the cular sling around the mid-vagina. The lower vagina is surrounded by
ilioinguinal nerve (L1), the posterior two-thirds are supplied by the the skeletal muscle fibres of bulbospongiosus (see Fig. 77.4). As the
pudendal nerve through the posterior labial branches of the perineal ureters pass anteromedially to reach the fundus of the bladder, they
nerve (S3), and the lateral aspect is also innervated by the perineal pass close to the lateral fornices, where care must be taken to avoid
branch of the posterior cutaneous nerve of the thigh (S2). Vulvar nerves damage during hysterectomy (Fig. 77.7). As they enter the bladder, the
are susceptible to trauma and inflammation, leading to vulvar pain ureters are usually anterior to the vagina; at this point, each ureter is
syndromes or vulvodynia (Shoja et al 2013). crossed transversely by a uterine artery (Fig. 77.8). | 1,783 | 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 77.1 Lymphatic drainage of the female genitalia
Structure Nodes
Vulva
Labia, clitoris, and perineum Superficial inguinal nodes
Perineum and lower labia majora Rectal lymphatic plexus
Clitoris Superficial inguinal nodes
Direct to deep inguinal nodes
Direct to internal iliac nodes
Vagina
Upper vagina Internal and external iliac nodes
Mid-vagina Internal iliac nodes
Lower vagina Superficial inguinal nodes
Uterus
Fundus Para-aortic nodes
Isthmus of tube and round ligament Superficial inguinal nodes
Body of uterus, including cervix External iliac nodes
Internal iliac nodes
Obturator nodes
Uterine (Fallopian) tubes Para-aortic nodes
Internal iliac nodes
Superficial inguinal nodes
Ovaries Para-aortic nodes | 1,784 | 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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T12 Fig. 77.5 The autonomic innervation of the
female reproductive system. (Based on Barucha
Paravertebral sympathetic chain AE 2006 Pelvic floor: anatomy and function.
L1 Neurogastroenterol Motil 18:507–19.)
L2
Aortic plexus
L3
L4
Lumbar splanchnic nerves
L5
Superior hypogastric plexus
Left hypogastric nerve
Right hypogastric nerve S1
S2
S3
Pelvic splanchnic nerves
S4
Uterovaginal plexus
S5
Pudendal nerve
Vesical plexus Inferior hypogastric plexus
Middle rectal plexus
Inferior rectal nerve
Perineal nerve
Anterior fornix Anterior lip Fig. 77.6 The cervix after it has been ruptured. It has no established function. The hymen
Cervical os of vagina of cervix Left vaginal wall and vaginal fornices, as may be imperforate; this is usually detected in adolescence.
seen via a Cusco’s Remnants of the duct of Gartner (embryologically, the caudal end
bivalve speculum. of the mesonephric duct) (see Figs 72.13, 72.19) are occasionally seen
protruding through the lateral fornices or lateral parts of the vagina and
may cause cysts (Gartner’s cysts). Prepubertal distal longitudinal folds
are common within the vagina and they disappear during puberty
(Altchek et al 2008).
Vascular supply and lymphatic drainage
Arteries
The arterial supply of the vagina is derived from the internal iliac arter-
ies by two median longitudinal vessels, the azygos arteries of the vagina,
which descend anterior and posterior to the vagina; they also supply
the vestibular bulb, fundus of the bladder, and adjacent part of the
rectum (see Fig. 77.3A). The uterine, internal pudendal and middle
rectal branches of the internal iliac artery may contribute to the blood
Right Posterior fornix Posterior lip of Cusco’s speculum
supply of the vagina.
vaginal wall of vagina cervix
Veins
The vagina opens externally via a sagittal introitus positioned below The vaginal veins, one on each side, arise from lateral plexuses that
the urethral meatus (see Fig. 77.1C). The size of the introitus varies; it connect with uterine, vesical and rectal plexuses and drain to the inter-
is capable of great distension during childbirth and, to a lesser degree, nal iliac veins. The uterine and vaginal plexuses may provide collateral
during sexual intercourse. The hymen is a thin fold of mucous mem- venous drainage to the lower limb.
brane situated just within the vaginal orifice. The internal surfaces of
Lymphatic drainage
the folds are normally in contact with each other and the vaginal
opening appears as a cleft between them. The hymen varies greatly in Vaginal lymphatic vessels link with those of the cervix, rectum and
shape and dimensions. When stretched, it is anular and widest poste- vulva. They form three groups but the regions drained are not sharply
riorly; it may also be semilunar and concave towards the mons pubis, demarcated. Upper vessels accompany the uterine artery to the internal
cribriform, fringed, absent or complete and imperforate. The hymenal and external iliac nodes; intermediate vessels accompany the vaginal
ring normally ruptures after first sexual intercourse, but can rupture artery to the internal iliac nodes; and vessels draining the vagina below
earlier during non-sexual physical activity. Small round carunculae the hymen, and from the vulva and perineal skin, pass to the superficial
hymenales (also known as carunculae myrtiformis) are its remnants inguinal nodes (see Table 77.1). | 1,785 | 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 lower vagina is supplied by the pudendal nerve (S2, S3 and S4).
The upper vagina is supplied by the pelvic splanchnic nerves (S2, S3
and, sometimes, S4) (see Fig. 77.5 and Table 77.2).
Abdominal aorta
Developmental anomalies of the vagina
Ovarian artery
Congenital anomalies of the vagina are vaginal agenesis, absent hymen,
transverse vaginal septum and persistent cloaca. Vaginal agenesis, in
the presence of other Müllerian duct anomalies and renal agenesis,
is termed Mayer–Rokistansky–Kuster–Hauser syndrome. An absent
hymen in patients with vaginal agenesis is associated with renal agen-
Uterine tube esis (Kimberley et al 2012). A congenital transverse septum may be
present within the vagina and manifests clinically in adolescence with
primary amenorrhoea and haematocolpos. Children with a persistent
cloaca have a congenital defect characterized by fusion of the rectum,
2 vagina and urethra into a single common channel that varies in length
from 1 to 7 cm.
Microstructure
Ovary
Uterus The vagina has an inner mucosal and an external muscular layer. The
1 Ureter
mucosa adheres firmly to the muscular layer. There are two median
Uterine artery longitudinal ridges on its epithelial surface: one anterior and the other
posterior. Numerous transverse bilateral rugae extend from these
3 vaginal columns, divided by sulci of variable depth, giving an appear-
ance of conical papillae. These transverse rugosities are most numerous
Bladder on the posterior wall and near the orifice; they increase under the influ-
ence of oestrogen during puberty and pregnancy, are especially well
developed before parturition, and decrease after the menopause (Corton
2012). The epithelium is non-keratinized, stratified, squamous similar
Vagina to, and continuous with, that of the ectocervix. After puberty, it thickens
and its superficial cells accumulate glycogen, which gives them a clear
appearance in histological preparations.
Fig. 77.7 The most common sites of ureteric injury during hysterectomy.
The vaginal epithelium does not change markedly during the men-
Key: 1, distal ureter at the level of the uterine artery; 2, dorsal to the
strual cycle, but its glycogen content increases after ovulation and then
infundibulopelvic ligament, near the pelvic bone; 3, intramural portion of
diminishes towards the end of the cycle. Natural vaginal bacteria, par-
ureter at the angle of the vaginal cuff.
ticularly Lactobacillus acidophilus, break down glycogen in the desqua-
mated cellular debris to lactic acid. This produces a highly acidic (pH
3) environment that inhibits the growth of most other microorganisms.
The amount of glycogen is less before puberty and after the menopause,
when vaginal infections are more common. There are no mucous
glands, but a fluid transudate from the lamina propria and mucus from
the cervical glands lubricate the vagina (Fig. 77.9). The muscular layers
are composed of smooth muscle and consist of a thick outer longitu-
dinal and an inner circular layer; the two layers are not distinct but are
Median sacral artery
Ovarian artery
Ovarian
vessels
E
Ureter
Ureter
Broad
ligament
Vaginal Uterine
artery artery
Branches of
anterior trunk
of internal
iliac artery
Fig. 77.9 Stratified squamous non-keratinizing epithelium (E) covering the
Fig. 77.8 The relationship of the ureter to the uterine and vaginal arteries. ectocervix and vagina. The cells of the middle and upper layers appear
(With permission from Drake RL, Vogl AW, Mitchell A (eds), Gray’s clear due to their glycogen content. (Courtesy of Mr Peter Helliwell and
Anatomy for Students, 2nd ed, Elsevier, Churchill Livingstone. Copyright the late Dr Joseph Mathew, Department of Histopathology, Royal
2010.) Cornwall Hospitals Trust, UK.) | 1,786 | 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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O
C O
B
R
S V
R
A
A B
B S
U
C V
I I
A
R
C D
Fig. 77.10 T2-weighted magnetic resonance images through the pelvis, demonstrating the normal female anatomy. A, Sagittal view. Abbreviations: A,
anus; B, bladder; C, cervix; R, rectum; S, pubic symphysis; V, vagina; *, endometrium; **, inner myometrium of uterus (also known as the junctional
zone); ***, outer myometrium of uterus. B–D, Axial views. B, Abbreviations: O, ovaries; R, rectum; *, endometrium, **, inner myometrium of uterus
(junctional zone); ***, outer myometrium of uterus. C, Abbreviations: B, bladder; C, cervix (which, from external to internal, has several layers, as seen on
T2-weighted images: a high-signal-intensity outer cervical stroma (contiguous with the outer myometrium); a low-signal-intensity inner cervical stroma
(contiguous with the inner myometrium); high-signal-intensity endocervical glands (contiguous with endometrium); and a very high-signal-intensity
endocervical canal (contiguous with the endometrial canal)); R, rectum. D, Abbreviations: A, anus; I, ischio-anal fossa; S, pubic symphysis; U, urethra; V,
vagina.
connected by oblique interlacing fibres. The longitudinal fibres are In the adult nulliparous state, the cervix usually tilts forwards relative
continuous with the superficial muscle fibres of the uterus. A layer of to the axis of the vagina (anteversion), and the body of the uterus tilts
loose connective tissue, containing extensive vascular plexuses, sur- forwards relative to the cervix (anteflexion) (see Fig. 77.12). In 10–15%
rounds the muscle layers. of women, the whole uterus leans backwards at an angle to the vagina
and is said to be retroverted. A uterus that angles backwards on the
cervix is described as retroflexed.
UPPER GENITAL TRACT
Body
UTERUS
The body of the uterus is pear-shaped and extends from the fundus
The uterus is a thick-walled, muscular organ situated in the pelvis superiorly to the cervix inferiorly. The uterine tubes enter the uterus on
between the urinary bladder and the rectum (Figs 77.10–77.12). It lies both sides at the uterine cornua. The round and ovarian ligaments are
posterior to the bladder and uterovesical space, and anterior to the inferoanterior and inferoposterior, respectively, to each cornu. The
rectum and recto-uterine pouch; it is mobile, which means that its posi- dome-like fundus is superior to the entry points of the uterine tubes
tion varies with distension of the bladder and rectum. The broad liga- and covered by peritoneum that is continuous with that of neighbour-
ments are lateral. ing surfaces. The fundus is in contact with coils of small intestine and,
The uterus is divided structurally and functionally into two main occasionally, by distended sigmoid colon. The lateral margins of the
regions: the muscular body of the uterus (corpus uteri) forms the upper body are convex; on each side, their peritoneum is reflected laterally to
two-thirds, and the fibrous cervix (cervix uteri) forms the lower third. form the broad ligament, which extends as a flat sheet to the pelvic wall | 1,787 | 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 77.2 Innervation of the female genitalia
Origin Proximal course Distal course Organ Function
Parasympathetic S2–S4 Pelvic splanchnic nerves Pelvic ganglia Uterine tube Vasodilation
Uterus
Cavernous (deep, cavernosal) nerves of clitoris Vagina Transudation
Clitoris Erection
Sympathetic T12, L1–L2 Superior mesenteric and renal plexus Ovarian plexus Ovary Vasoconstriction
Superior hypogastric plexus Hypogastric nerve
↓
Inferior hypogastric plexus
↓
Uterovaginal plexus (Frankenhäuser’s ganglion) Uterine tube, uterus, upper vagina Contraction
Somatic S2, 3, 4 Pudendal nerve Dorsal nerve of clitoris Clitoris
Pudendal nerve Posterior labial nerves Lower vagina Contraction
Labia majora
Ischiocavernosus
Bulbospongiosus
(With permission from Shoja MM, Sharma A, Mirzaya N, Groat C, Watanabe K, Loukas M and Tubbs RS. Neuroanatomy of the Female Abdominoplevic Region: A Review with Application to Pelvic Pain Syndromes. Clinical
Anatomy 26:66–76, 2013.) | 1,788 | 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
Axis of
uterine body Axis of vagina
Ovary and
uterine tube
Round ligament Recto-
of uterus uterine pouch
Uterus
Rectum
Vesico-uterine
pouch Vaginal
vault
Bladder
Vagina Axis of cervix
Pubis
Greater Angle of
Urethra vestibular gland anteflexion
Clitoris Bulb of vestibule
Angle of anteversion
B
Fig. 77.12 Angles of anteflexion and anteversion. (With permission from
Drake RL, Vogl AW, Mitchell A (eds), Gray’s Anatomy for Students, 2nd
ed, Elsevier, Churchill Livingstone. Copyright 2010.)
size of the uterus until approximately 7 years of age, when there is
Ureter Recto-uterine greater enlargement of the body of the uterus than the cervix.
fold
Broad ligament Developmental anomalies of the uterus There may be failure
Round ligament in fusion of the paramesonephric (Müllerian) ducts, which results in a
of uterus uterus that is not pear-shaped. There may only be a septum (septate
Inferior uterus) or partial clefting of the uterus (bicornuate uterus); the most
epigastric artery extreme example is a septate vagina, two cervices and two discrete uteri,
each with one uterine tube (uterus didelphys) (Minto et al 2001) (see
Fig. 72.15).
Lateral umbilical fold
Cervix
Medial umbilical fold Recto-uterine
The adult, non-pregnant cervix is narrower and more cylindrical than the
pouch
body of the uterus and is typically 2.5 cm long. The upper end commu-
nicates with the uterine body via the internal os, and the lower end opens
Median umbilical fold
into the vagina at the external os (see Fig. 77.6). In nulliparous women,
Vesico-uterine pouch
the external os is usually a circular aperture, whereas, after childbirth, it
is a transverse slit. Two longitudinal ridges, one each on its anterior and
Fig. 77.11 A, Anatomical relations of the female genital tract, bladder and posterior walls, give off small, oblique, palmate folds that ascend later-
rectum. B, Pelvic peritoneal reflections, showing the broad ligament and
ally like the branches of a tree (arbor vitae uteri); the folds on opposing
its contents. (A, With permission from Drake RL, Vogl AW, Mitchell A,
walls interdigitate to close the canal. The narrower isthmus forms the
Tibbitts R, Richardson P (eds), Gray’s Atlas of Anatomy, Elsevier,
upper third of the cervix. Although unaffected in the first month of
Churchill Livingstone. Copyright 2008. B, With permission from Drake RL,
pregnancy, it is gradually taken up into the uterine body during the
Vogl AW, Mitchell A (eds), Gray’s Anatomy for Students, 2nd ed, Elsevier,
second month to form the ‘lower uterine segment’ (see below). In non-
Churchill Livingstone. Copyright 2010.)
pregnant women, the isthmus undergoes menstrual changes, although
these are less pronounced than those occurring in the uterine body. The
external end of the cervix enters the upper end of the vagina, thereby
(see Figs 77.11B, 77.15). The anterior surface of the uterine body is dividing the cervix into supravaginal and vaginal parts. The supravaginal
covered by peritoneum reflected on to the bladder at the uterovesical part is separated anteriorly from the bladder by cellular connective tissue:
fold (see Fig. 77.14). This normally occurs at the level of the internal the parametrium, which also passes to the sides of the cervix and laterally
os, the most inferior margin of the body of the uterus. The vesico- between the two layers of the broad ligaments.
uterine pouch, between the bladder and uterus, is obliterated when the
bladder is distended, but may be occupied by small intestine when the Peritoneal folds and ligaments of the pelvis
bladder is empty. The posterior surface of the uterus is convex trans-
versely. Its peritoneal covering continues down to the cervix and upper The uterus is connected to a number of ‘ligaments’. Some are true liga-
vagina, and is then reflected back to the rectum along the surface of the ments, in that they have a fibrous composition and provide support to
recto-uterine pouch, which lies posterior to the uterus (see Fig. 77.16). the uterus; some provide no support to the uterus; and others are simply
The sigmoid colon, and occasionally the terminal ileum, lie posterior folds of peritoneum.
to the uterus.
The cavity of the uterine body usually measures 6 cm from the Peritoneal folds
external os of the cervix to the wall of the fundus and is flat in its The parietal peritoneum is reflected over the upper genital tract to
anteroposterior plane (Salardi et al 1985). In coronal section, it is tri- produce anterior (uterovesical), posterior (rectovaginal) and lateral
angular, broad above where the two uterine tubes join the uterus, and peritoneal folds. The lateral folds are commonly called the broad liga-
narrow below at the internal os of the cervix. There is no change in the ments (Fig. 77.13). | 1,789 | 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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Round ligament Ovary Uterus Uterus Recto-uterine pouch Round ligament External iliac artery
Broad ligament Rectum Uterine tube
Rectum Uterine tube Broad ligament
Fig. 77.13 A laparoscopic view of the uterus. The patient is tilted head
Fig. 77.15 A laparoscopic view of the broad ligament.
down so that the small bowel is moved away from the uterus to give this
view.
Catheter balloon in bladder Uterovesical fold Ovary Uterus Recto-uterine pouch Uterosacral ligament
Uterine tube Uterus Rectum Uterine tube Sigmoid colon descending Ovarian vessels
Fig. 77.14 A laparoscopic view of the anterior part of the pelvis, showing to rectum
the uterovesical fold anterior to the uterus. Fig. 77.16 A laparoscopic view of the posterior pelvis, showing the
recto-uterine pouch (pouch of Douglas) with the sigmoid colon
descending towards the rectum.
uterovesical and rectovaginal folds
The anterior, or uterovesical, fold consists of peritoneum reflected on
to the bladder from the uterus at the junction of its cervix and body Mesosalpinx
(Fig. 77.14). The posterior or rectovaginal fold extends lower than the The mesosalpinx is attached above to the uterine tube and posteroin-
anterior fold and consists of peritoneum reflected from the posterior feriorly to the mesovarium (see Fig. 77.17). Superior and laterally, it is
vaginal fornix on to the front of the rectum, thereby creating the deep attached to the suspensory ligament of the ovary; medially, it is attached
recto-uterine pouch (pouch of Douglas). The recto-uterine pouch is to the ovarian ligament. The fimbria of the tubal infundibulum projects
bounded anteriorly by the uterus, supravaginal cervix and posterior from its free lateral end. Between the ovary and uterine tube, the mes-
vaginal fornix; posteriorly, by the rectum; and laterally, by the uterosac- osalpinx contains vascular anastomoses between the uterine and
ral ligaments. ovarian vessels, the epoophoron and the paroophoron. The meso-
varium projects from the posterior aspect of the broad ligament, of
Broad ligament which it is the smaller part. It is attached to the hilum of the ovary and
The lateral folds, or broad ligaments, extend on each side from the carries vessels and nerves to the ovary.
uterus to the lateral pelvic walls, where they become continuous with
the peritoneum covering those walls (Figs 77.15, 77.17–77.18). The Mesometrium
upper border is free and the lower border is continuous with the peri- The mesometrium is the largest part of the broad ligament, and extends
toneum over the bladder, rectum and side wall of the pelvis. The borders from the pelvic floor to the ovarian ligament and uterine body. The
are continuous with each other at the free edge via the uterine fundus, uterine artery passes between its two peritoneal layers typically 1.5 cm
and diverge below near the superior surfaces of levatores ani. A uterine lateral to the cervix; it crosses the ureter shortly after its origin from the
tube lies in the upper free border on either side. The broad ligament is internal iliac artery and gives off a branch that passes superiorly to the
divided into an upper mesosalpinx, a posterior mesovarium and an uterine tube, where it anastomoses with the ovarian artery (Fig. 77.19).
inferior mesometrium. Between the pyramid formed by the infundibulum of the tube, the | 1,790 | 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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Fig. 77.17 Pelvic peritoneal
reflections, demonstrating the
broad ligament and its contents.
Ovarian vessels (With permission from Drake RL,
Vogl AW, Mitchell A (eds),
Ureter
Gray’s Anatomy for Students,
2nd ed, Elsevier, Churchill
Livingstone. Copyright 2010.)
Broad ligament
Suspensory ligament
of ovary
Mesovarium
Deep inguinal ring
Round ligament
Sagittal section of broad ligament
of the uterus
Mesosalpinx
Uterine
Inguinal canal Ovary
tube
Ligament of ovary Mesovarium
Superficial inguinal ring Broad
ligament
Ureter
Labium majus
Uterine artery
Rectum
Fundus of uterus
Ureter
Uterine tube, fimbriae
Vermiform appendix
Ovarian artery and vein
Caecum
Suspensory ligament of
ovary (infundibulopelvic
ligament)
Uterine tube, ampulla Uterine tube, infundibulum
Uterine tube, ampulla
Ovary, medial surface
Mesosalpinx
Mesovarian border
Uterine tube, isthmus
Ligament of ovary
Broad ligament of uterus
Round ligament of uterus
Vesico-uterine pouch
Medial umbilical fold
Urinary bladder
Uterus, vesical surface Median umbilical fold
Fig. 77.18 The ovaries and broad ligament: superior view with the uterus lifted away from the bladder. (With permission from Waschke J, Paulsen F
(eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
upper pole of the ovary, and the lateral pelvic wall, the mesometrium neither attachment nor extension to the caudal labium (the homologue
contains the ovarian vessels and nerves lying within the fibrous suspen- of the hemiscrotum) (Attah and Hutson 1991). Near the uterus, the
sory ligament of the ovary (infundibulopelvic ligament). This ligament round ligament contains a considerable amount of smooth muscle but
continues laterally over the external iliac vessels as a distinct fold. The this gradually diminishes and the terminal portion is purely fibrous.
mesometrium also encloses the proximal part of the round ligament of The round ligament also contains striated muscle, blood vessels, nerves
the uterus, as well as smooth muscle and loose connective tissue. and lymphatics. The latter drain the uterine region around the entry of
the uterine tube to the superficial inguinal lymph nodes.
Ligaments of the pelvis
In the fetus, a projection of peritoneum (processus vaginalis) is
The ligaments of the pelvis consist of the round, uterosacral, transverse carried with the round ligament for a short distance into the inguinal
cervical and pubocervical ligaments. canal. This is generally obliterated in adults, although it is sometimes
patent even in old age. A patent processus vaginalis in the inguinal canal
Round ligament in females is often referred to as the canal of Nuck; it may be asymp-
Each round ligament is a narrow smooth muscle band 10–12 cm long, tomatic or it may give rise to an inguinal hernia or hydrocele of the
which extends from the lateral cornu of the uterus through the broad canal of Nuck. In the canal, the ligament receives the same coverings as
ligament to enter the deep inguinal ring lateral to the inferior epigastric the spermatic cord, although they are thinner and blend with the liga-
artery (see Figs 77.13, 77.15, 77.18). Although conventionally described ment itself, which may not reach the mons pubis. The round and
as ending in the labium majus, a cadaveric dissection study found that, ovarian ligaments both develop from the gubernaculum and are
in girls, the round ligament ended just outside the external ring, with continuous. | 1,791 | 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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uterosacral, transverse cervical and horizontal axis of the upper vagina. The uterus and vagina are supported
pubocervical ligaments by the close interaction of the uterosacral and transverse cervical liga-
ments with the muscles of the pelvic floor, including the levatores ani
The uterosacral, transverse cervical and pubocervical ligaments are con-
and coccygei, the perineal membrane and the perineal body. The
densations of the visceral or endopelvic connective tissue that connect
support of the pelvic floor has been reviewed in detail by Delancey
the pelvic viscera to the side wall of the pelvis; they radiate like the
(2011) (see also Ch. 73).
spokes of a wheel around the hub of the cervix, providing it with con-
siderable support (see Figs 77.13–16) (Delancey 2011). The connective
Vascular supply and lymphatic drainage
tissue lateral to the uterus and the cervix – the parametrium – continues
down along the vagina as the paracolpium. The uterosacral ligaments
contain fibrous tissue and smooth muscle. They pass back from the Arteries
cervix and uterine body on both sides of the rectum, and are attached The arterial supply to the uterus comes from the uterine artery (see Fig.
to the anterior aspect of the sacrum. They can be palpated laterally on 77.19; Fig. 77.21), which arises as a branch of the anterior division of
rectal examination and can be felt as thick bands of tissue passing the internal iliac artery. From its origin, the uterine artery crosses the
downwards on both sides of the posterior fornix on vaginal examina- ureter anteriorly in the broad ligament before branching as it reaches
tion. The transverse cervical ligaments (cardinal ligaments, ligaments of the uterus at the level of the cervico-uterine junction (see Fig. 74.21B).
Mackenrodt) (Fig. 77.20) extend from the side of the cervix and lateral One major branch ascends the uterus tortuously within the broad liga-
fornix of the vagina, and are attached extensively on the pelvic wall. ment until it reaches the region of the ovarian hilum, where it anasto-
The lower parts of the ureters and pelvic blood vessels traverse the moses with branches of the ovarian artery. Another branch descends to
transverse cervical ligaments. Fibres of the pubocervical ligament pass supply the cervix and anastomoses with branches of the vaginal artery
forwards from the anterior aspect of the cervix and upper vagina to to form two median longitudinal vessels: the azygos arteries of the
diverge around the urethra, and are attached to the posterior aspect of vagina, which descend anterior and posterior to the vagina. Although
the pubic bones. there are anastomoses with the ovarian and vaginal arteries, the domi-
The transverse cervical and uterosacral ligaments are almost verti- nance of the uterine artery is indicated by its marked hypertrophy
cally orientated in the standing position and maintain the near- during pregnancy.
The tortuosity of the vessels as they ascend in the broad ligaments
is repeated in their branches within the uterine wall. Each uterine artery
Fundus of uterus Ovarian artery and vein
gives off numerous branches. These enter the uterine wall, divide and
Ovary and tube Anastomosis of ovarian Mesosalpinx run circumferentially as groups of anterior and posterior arcuate arter-
and uterine vessels
ies. They ramify and narrow as they approach the anterior and posterior
midline so that no large vessels are present in these regions. However,
the left and right arterial trees anastomose across the midline and uni-
lateral ligation can be performed without serious effects. Terminal
branches in the uterine muscle are tortuous and are called helicine
arterioles. They provide a series of dense capillary plexuses in the myo-
metrium and endometrium. From the arcuate arteries, many helical
arteriolar rami pass into the endometrium. Their detailed appearance
Broad
ligament changes during the menstrual cycle. In the proliferative phase, helical
arterioles are less prominent, whereas they grow in length and calibre,
Uterine artery becoming even more tortuous in the secretory phase.
and vein
Veins
Ureter
The uterine veins extend laterally in the broad ligaments, running adja-
cent to the arteries and passing over the ureters. They drain into the
Vagina internal iliac veins (see Fig. 77.3). The uterine venous plexus anasto-
moses with the vaginal and ovarian venous plexuses.
Lymphatic drainage
Fig. 77.19 The broad ligament (left), and blood supply to the uterus and Uterine lymphatics exist in the superficial (subperitoneal) and deep
ovaries (right). (With permission from Drake RL, Vogl AW, Mitchell A, parts of the uterine wall. Collecting vessels from the body of the uterus
Tibbitts R, Richardson P (eds), Gray’s Atlas of Anatomy, Elsevier, and cervix pass laterally in the parametrium to three main groups of
Churchill Livingstone. Copyright 2008.) lymph nodes: the external and internal iliac and the obturator nodes
Fig. 77.20 The supporting ligaments of the
pelvis, showing the transverse cervical
ligaments. (With permission from Waschke
J, Paulsen F (eds), Sobotta Atlas of Human
Anatomy, 15th ed, Elsevier, Urban &
Sacroiliac joint
Fischer. Copyright 2013.)
Pararectal space
Retrorectal space
Recto-uterine ligament
Rectum
Rectouterine pouch
Transverse cervical ligament
Cervix uteri
(cardinal ligament)
Uterovesicular pouch
Paravesical space
Ureter
Urinary bladder
Ureteric orifice
Retropubic space
Internal urethral orifice
Pubic symphysis | 1,792 | 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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Suspensory ligament of ovary
(infundibulopelvic ligament)
Uterine tube
Ovarian artery
Tubal branch
Fundus of uterus
Ovary
Branch to fundus
Ovarian branch
of uterus
Ligament of ovary
Helicine arterioles
B 56% C 40%
Uterine artery >90%
Vaginal branch
A
D 4% E 90% F 10%
Fig. 77.21 A, The normal arterial supply to the uterus and ovary. B–D, Variations in arterial blood supply to the ovary. E–F, Variations in arterial blood
supply to the fundus of the uterus. (A, With permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban &
Fischer. Copyright 2013.)
(see Table 77.1). The external and internal iliac nodes surround their Endometrium
corresponding arteries. The obturator nodes lie in the obturator fossa The endometrium is formed by a layer of connective tissue, the endome-
between the external and internal iliac vessels; the obturator nerve trial stroma, which supports a single-layered columnar epithelium.
passes through the lower part of this group of lymph nodes. Before puberty, the epithelium is ciliated and cuboidal. It contains
Lymph vessels from the fundus of the uterus and the uterine glands that are composed largely of columnar cells secreting glycopro-
tubes may accompany the lymph drainage of the ovaries to para-aortic teins and glycogen. After puberty, the structure of the endometrium
nodes (see Fig. 77.3B). The region surrounding the isthmus of the varies with the stage of the menstrual cycle (see below). The glands are
uterine tube may drain along the round ligament to the superficial tubular, run perpendicular to the luminal surface and penetrate up to
inguinal nodes. the myometrial layer. The stroma consists of a highly cellular connective
tissue between the endometrial glands, and contains blood and lym-
Innervation phatic vessels.
myometrium
The nerve supply to the uterus is predominantly from the inferior hypogas-
tric plexus (see Fig. 77.5) (Shoja et al 2013). Some branches ascend with, The myometrium is composed of smooth muscle and loose connective
or near, the uterine arteries in the broad ligament. They supply the uterine tissue, and contains blood vessels, lymphatic vessels and nerves. It is
body and tubes, and connect with tubal nerves from the inferior hypogas- dense and thick at the uterine midlevel and fundus but thin at the tubal
tric plexus and with the ovarian plexus. The uterine nerves terminate in orifices. The body of the uterus has four muscular layers. The submu-
the myometrium and endometrium, and usually accompany the vessels cosal (innermost) layer is composed of longitudinal and some oblique
(see Table 77.2). Nerves to the cervix form a plexus that contains small smooth muscle fibres. Where the lumen of the uterine tube passes
paracervical ganglia. Sometimes, one ganglion is larger and is termed the through the uterine wall, this layer forms a circular muscle coat. The
uterine cervical ganglion. Branches may pass directly to the cervix uteri or vascular layer is external to the submucosal layer and is rich in blood
may be distributed along the vaginal arteries. vessels, as well as longitudinal muscle; it is succeeded by a layer of
Efferent preganglionic sympathetic fibres are derived from neurones predominantly circular muscle, the supravascular layer. The outer, thin,
in the last thoracic and first lumbar spinal segments; the sites where longitudinal muscle layer, the subserosal layer, lies adjacent to the
they synapse on their postganglionic neurones are unknown but are serosa.
presumably in the superior and/or inferior hypogastric plexuses (Lee The muscular fibres of the outer two layers converge at the lateral
et al 1973). Preganglionic parasympathetic fibres arise from neurones angles of the uterus and continue into the uterine tubes. Some fibres
in the second to fourth sacral spinal segments and relay in the paracervi- enter the broad ligaments as the round and ovarian ligaments; others
cal ganglia. Sympathetic activity may produce uterine contraction and turn back into the uterosacral ligaments. At the junction between the
vasoconstriction, and parasympathetic activity may produce uterine body and the cervix, the smooth muscle merges with dense, irregular
inhibition and vasodilation, but these activities are complicated by connective tissue containing both collagen and elastin, and forms the
hormonal control of uterine functions. majority of the cervical wall. Bilateral longitudinal fibres extend in the
lateral submucosal layer from the fundal angle to the cervix. Their
Microstructure muscle fibres differ structurally from those of typical myometrium, and
they may provide fast-conducting pathways that coordinate the contrac-
tile activities of the uterine wall.
Body of the uterus
The uterus is composed of three main layers. From its lumen outwards, serosa
these are the endometrium (mucosa), myometrium (smooth muscle The uterine body is covered by peritoneal serosa, which continues
layer) and serosa (or adventitia) (Fig. 77.22). downwards posteriorly to cover the supravaginal cervix. The anterior | 1,793 | 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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Ligament of ovary
Ovarian stroma
Uterine tube, isthmus Mesosalpinx
Fundus of uterus
Uterine tube, ampulla
Uterine tube Transverse ductules
Uterine tube, folds
Round ligament of uterus
Ligament of ovary
Uterine tube,
infundibulum;
fimbriae
Uterine cavity, endometrium
Myometrium Corpus albicans
Ovarian artery and veins
Cervical canal, palmate folds
Vesicular appendix (stalked hydatid)
Cervix of uterus, vaginal part
Vesicular ovarian follicles
External os of uterus Corpus luteum
Broad ligament of uterus
Uterine ostium,
Vagina Uterine tube, uterine part
intramural part
Cervix of uterus, supravaginal part Body of uterus
Isthmus of uterus
Fig. 77.22 The uterus, uterine tubes and ovaries. (With permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier,
Urban & Fischer. Copyright 2013.)
EEGG
BV
L
LP
E
EC
EC
Fig. 77.23 The endocervical glands. These are are deep infoldings of the
lining of the endocervical canal (EC). The epithelium (E) is simple
columnar and mucus-secreting. The underlying lamina propria (LP) is
richly supplied with blood vessels (BV) and lymphatics (L). (Courtesy of Mr
Peter Helliwell and the late Dr Joseph Mathew, Department of
Histopathology, Royal Cornwall Hospitals Trust, UK.)
Fig. 77.24 The transformation zone of the uterine cervix. The single-
cervix and the lateral surfaces of the uterine body and cervix are not layered columnar epithelium lining the endocervical canal (EC) and its
covered by peritoneum. endocervical glands (EG) changes abruptly (arrow) to the stratified
squamous non-keratinizing epithelium of the external os and ectocervix
Cervix uteri
(below arrow).
The cervix consists of fibroelastic connective tissue and contains rela-
tively little (10%) smooth muscle. The elastin component of the cervical
stroma is essential to the stretching capacity of the cervix during child- The squamocolumnar junction, where the columnar secretory epi-
birth. The cervical canal is lined by a deeply folded mucosa with a thelium of the endocervical canal meets the stratified squamous cover-
surface epithelium of columnar mucous cells (Fig. 77.23). There are ing of the ectocervix, is located at the external os before puberty. As
branched tubular glands present within the mucosa, which are lined by oestrogen levels rise during puberty, the cervical os opens, exposing the
a similar secretory epithelium. The glands extend obliquely upwards endocervical columnar epithelium on to the ectocervix. This area of
and outwards from the canal. They secrete clear, alkaline mucus, which columnar cells on the ectocervix forms an area that is red and raw in
is relatively viscous except at the midpoint of the menstrual cycle, when appearance, called an ectropion (cervical erosion). It is then exposed to
it becomes more copious and less viscous to encourage the passage of the acidic environment of the vagina and, through a process of squa-
sperm. At the vaginal end of the cervix, the aperture of a gland may mous metaplasia (p. 40), transforms into stratified squamous epithe-
block and it then fills with mucus to form a Nabothian follicle (or cyst). lium. This area is thus known as the ‘transformation zone’ (Fig. 77.24).
None of the mucosa is shed during menstruation and so, unlike the Other hyperoestrogenic states, such as pregnancy and the use of oral
body of the uterus, it is not divided into functional and basal layers, contraceptive pills, can also result in an ectropion. This area is the most
and lacks spiral arteries. The surface of the intravaginal part of the cervix usual site of cervical intraepithelial neoplasia (CIN), which may
(ectocervix) is covered by non-keratinizing stratified squamous epithe- progress to malignancy. In postmenopausal women, the squamocolum-
lium, which contains glycogen. nar junction recedes into the endocervical canal. | 1,794 | 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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Magnetic resonance imaging of the uterus In prepubertal females, the uterus is smaller (only 4 cm in length),
and vagina and on T2-weighted images, the endometrium is minimal or absent,
and the junctional zone is indistinct. In postmenopausal women, the
corpus decreases in size and the zonal anatomy is indistinct.
On T2-weighted magnetic resonance imaging (MRI), the uterus displays
On T2-weighted MRI, the cervix has an inner, low-signal stroma
a zonal anatomy, with three distinct zones: the endometrium, junc-
continuous with the junctional zone of the uterus. Often, this is sur-
tional zone and myometrium (Fig. 77.25) (Minto et al 2011). The
rounded by an outer zone of intermediate signal intensity, which is
endometrium and uterine cavity appear as a high-signal stripe; the
continuous with the outer myometrium. The appearances do not
thickness varies with the stage of the menstrual cycle. In the early pro-
change with the menstrual cycle or oral contraceptive pill use. The
liferative phase, it measures up to 5 mm, and widens to up to 1 cm in
central stripe is very high-signal and is a consequence of the secretions
the mid-secretory phase. A band of low signal, the junctional zone,
produced by the endocervical glands.
borders the endometrium. It represents the inner myometrium and is
The vagina is best seen on T2-weighted MRI as a thin layer of high-
of constant thickness and signal throughout the menstrual cycle; it
signal intensity of the mucosa and an outer, low-signal layer of the
usually measures 5 mm. The outer myometrium is of medium-signal
submucosa and muscularis (see Fig. 77.25). MRI accurately demon-
intensity in the proliferative phase, and of high-signal intensity in the
strates congenital and acquired Müllerian anomalies, including uterine
mid-secretory phase as a result of the increased vascularity and promi-
and vaginal aplasia, duplication and septa (Grant et al 2010). Vaginal
nence of the arcuate vessels.
and perivaginal cysts are well visualized with T2-weighted MRI.
High-signal stroma Left ovary
at hilum of right ovary UTERINE (FALLOPIAN) TUBES
The uterine tubes are attached to the upper part of the body of the
uterus, and their ostia open into the uterine cavity (Figs 77.26, 77.27,
77.28). The medial opening of the tube (the uterine os) is located at
the superior angle of the uterine cavity. The tube passes laterally and
superiorly, and consists of four main parts: intramural, isthmus, ampulla
and fimbria (see Fig. 77.22). The intramural part is 0.7 mm wide and
1 cm long, and lies within the myometrium. It is continuous laterally
with the isthmus, which is 1–5 mm wide and 3 cm long; it is rounded,
muscular and firm. The isthmus is continuous laterally with the
ampulla, the widest portion of the tube with a maximum luminal
diameter of 1 cm. The ampulla is 5 cm long and has a thin wall and a
tortuously folded luminal surface. Typically, fertilization takes place in
its lumen. The ampulla opens into the trumpet-shaped infundibulum
at the abdominal os. Fimbriae, numerous mucosal finger-like folds
1 mm wide, are attached to the ends of the infundibulum and extend
from its inner circumference beyond the muscular wall of the tube. One
of these, the ovarian fimbria, is longer and more deeply grooved than
the others, and is typically applied to the tubal pole of the ovary. At the
time of ovulation, the fimbriae swell and extend as a result of engorge-
ment of the vessels in the lamina propria, which aids capture of the
released oocyte. All fimbriae are covered, like the mucosal lining
A
throughout the tube, by a ciliated epithelium whose cilia beat towards
the ampulla.
Small follicles in Urinary Uterus
low-signal outer stroma bladder Vascular supply and lymphatic drainage
Fluid in recto-uterine pouch
Myometrium Junctional zone (pouch of Douglas) Arteries
The blood supply to the uterine tubes is derived from ovarian and
uterine arteries (see Fig. 77.21A). The lateral third of the tube is supplied
by the ovarian artery, which continues in the mesosalpinx to anasto-
mose with branches from the uterine artery. The medial two-thirds of
the tube are supplied by the uterine artery.
Ostium of left uterine tube Fundus Ostium of right uterine tube
B
Bladder Endometrial cavity Vagina Cervix
Fig. 77.25 T2-weighted MRI scans of the uterus and ovaries. A, A coronal
T2-weighted MRI through a female pelvis showing the uterus and both
ovaries with the high-signal central stroma and lower-signal outer stroma.
B, A sagittal T2-weighted MRI through a female pelvis, showing the zonal
anatomy of the uterus. Fig. 77.26 A hysteroscopic view of the endometrial cavity of the uterus. | 1,795 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |