recursal/Fanatic-Fandom huggingface dataset:
Joint:Pelvis:Sacroiliac joints

The **sacroiliac (SI) joint**is a synovial and fibrous joint between ilium and the sacrum. It has little movement and its main function is to transfer weight between the axial and lower appendicular skeletons. The SI joint is a symmetrical joint (i.e. is paired) with an oblique coronal orientation and is located at the S1-3 level.

Articulation

The sacroiliac joint is formed by the irregularly-shaped auricular surfaces of the sacrum and the ilium. It is lined by hyaline cartilage. The capsule is attached to the articular margins and ligamentous bands surround the capsule.

Ligaments:

* interosseous sacroiliac ligament: from iliac tuberosity to the lateral mass of the sacrum; located posteriorly; thick and strong. Oriented superiorly & laterally. Weight transferred to sacrum, cause ligament to be pulled inward.
* Anterior sacroliliac ligament: flat band, joining bones above and below the pelvic brim.
* Posterior sacroiliac ligament: located superiorly to interosseous sacroiliac ligament. Posterior rami of spinal nerves and vessels pass between interosseous and posterior ligament.
* Iliolumbar ligament: a strong V shaped connective tissue which courses from the transverse process of L5 to iliac crest, and the front of the anterior sacroiliac ligament
* Sacrotuberous: Superior & inferior posterior iliac spines, sacrum & coccyx to ischial tuberosity
* Sacrospinous: Lateral sacrum & coccyx to ischial spine

Muscles

* latissimus dorsi (via thoracolumbar fascia)
* gluteus maximus
* piriformis

Nerve supply: via branches from the lumbosacral plexus:

* dorsal rami of S1 and S2
* superior gluteal nerve
* obturator nerve

Movements

Movement at the sacroiliac joint is minimal and is limited to gliding and rotation. Most movement is experienced during pregnancy due to laxity of ligaments and the joint typically fuses after the age 50.
Basal CSF cisterns:Suprasellar cistern

The **suprasellar cistern** (also known as **pentagon of basal cisterns**) is a cerebrospinal-fluid filled space located above the sella turcica, under the hypothalamus. It contains the optic chiasma, the infundibular stalk and the polygone of Willis. It has the shape of a pentagon at the level of the optic chiasma, and the shape of a six-point star at the level of cerebral peduncles, frequently likened to the star of David.
Bone: Hip Bone, Femur, and Patella: Bony features

Hip bone

Anterior superior iliac spine - anterior part of iliac crest, attachment of sartorius and inguinal ligament.

Anterior inferior iliac spine - anterior part of iliac bone, attachment of straight head of rectus remoris and iliofemoral ligament.

Posterior superior iliac spine - posterior part of the iliac crest. Attachment of multifidus and sacroiliac ligaments.

Posterior inferior iliac spine - most posterior part of auricular surface. Attachment of sacroiliac ligaments.

Obturator foramen - formed by the superior and inferior pubic rami, from both pubis and ischium.

Pubic tubercule - superomedial part of the superior pubic ramus. Attachment of inguinal ligament.

Greater sciatic foramen - formed by greater sciatic notch, and sacrotuberus, sacroiliac and sacrospinous ligaments.

Lesser sciatic foramen - formed by ischial spine and tuberosity, and sacrotuberus, sacrospinous ligaments.

Pectineal line - part of the pelvic brim, runs posterolaterally along the superior border of the superior iliac crest. Pectineus attaches here.

Ischial spine -

Ischial tuberosity - large process on the inferior part of the ischium. Multiple muscular attachements, and directly supports body weight when sitting.

Femur

Greater tuberosity

Lesser tuberosity

Linea aspera

Patella
Abdomen:Hollow viscus:Ileum

The **ileum** is the final section of the small intestine. The ileum is 2-4 m in length and is separated from the caecum by the ileocaecal valve(ICV).

There is no line of demarcation between the jejunum and the ileum. However, there are subtle differences between the two:

* the ileum has more fat inside the mesentery than the jejunum
* the ileum is a paler colour, and tends to be of a larger calibre as well
* the entire length of the intestinal tract contains lymphoid tissue, but only the ileum has abundant Peyer's patches
* circular folds within the lumen is more spaced apart.

The Peyer's patches contained in the ileum are white plaques in the mucous membrane consisting of unencapsulated lymphoid nodules that contain large amounts of lymphocytes and other cells of the immune system.

Blood supply:

* Ileal arteries from the SMA forming arcades (three to five) around the mesenteric edge of the ileum. The straight arteries are shorter.
* Veins corresponding to the arteries drain to the superior mesenteric artery.

Lymph drainage

Mesenteric nodes that follow arterial arcades

Nerve innervation: autonomic

* Sympathetic: Follow SMA and its branches, called the splanchnic nerves
	+ Effect: Reduce motility, secretion and vascularity
* Parasympathetic: Follow arterial branches
	+ Are branches of posterior vagal trunks
	+ Increase motility, secretion, vascularity & digestion
	+ Includes sensory branches that can detect stretching & distention, but no other pain stimuli; bowel obstruction → distended lumen → spasms of crampy abdominal pain (colic); poorly localized
Abdomen:Lymphatics:Cisterna chyli

The**cisterna chyli (CC)**is a normal anatomical structure seen as saccular area of dilatation in the lymphatic channels that is located in the retrocrural space (under the right crus) between the aorta and the azygos vein, usually to the immediate right of the abdominal aorta .

It at the level of L1/2 vertebral body and extends 5-7 cm in the caudocephalad axis.

It is formed by the confluence of the right and left lumbar (receive lymph from non-alimetary viscera, abdominal wall, and lower extremities), intestinal, and descending intercostal lymphatic trunks.

From there, the lymph channels continue to the thoracic duct to empty into the left subclavian vein.
Abdomen:Visceral arteries:SMA

The **superior mesenteric artery (SMA)** is one of the three non-paired arteries that provide blood to the gut and other abdominal viscera.

Origin

* Single vessel arising anteriorly from abdominal aorta at the level of L1.

Course

* Courses anteroinferiorly, *behind the neck of pancreas and splenic vein*, crossing anterior to the left renal vein.
* It emerges *anterior to the uncinate process* of the pancreas and crosses anterior to the third part of duodenum.
* It then enters the upper portion of the small bowel mesentery and runs *along the root of the mesentery* downwards to the right.
* Branches to the jejunum and ileum are given off to the left, and branches to the proximal and mid colon are given off to the right.
* The SMA terminates at the ileum as the ileal branch of the ileocolic artery.

The superior mesenteric vein (SMV) should always lie to the right of the SMA, otherwise malrotation should be suspected.

Branches

* **inferior pancreaticoduodenal artery:** divides anterior and posterior branches that pass in the curve between the duodenum and head of the pancreas supplies duodenum (distal to bile duct), pancreas, and spleen
	+ anastomose with the superior pancreaticoduodenal artery

Left-sided: passes down in the small bowel mesentery

* **jejunal branches**
* **ileal branches**

Right-sided

* **ileocolic artery:** arise from right side of the SMA, at the base of the mesentery, it pass to the right iliac fossa and divides into superior and inferior branches.
	+ The superior branch runs along the left side of the ascending colon
	+ The inferior branch runs to the ileocolic junction and gives anterior and posterior caecal arteries and appendicular artery, and ileal branch which supplies terminal ileum, cecum, appendix, and proximal ascending colon
* **right colic artery:** runs across the right psoas muscles, gonadal vessels, ureter behind the peritoneal floor of the right infracolic compartment to supply the ascending colon.
* **middle colic artery:** supplies proximal 2/3 of transverse colon, up to splenic flexure

Marginal artery of Drummond

The terminal branches of the ileocolic, right colic and middle colic arteries along with the terminal branches of the left colic artery and sigmoid branches of the IMA form a continuous arterial circle or arcade along the inner border of the colon known as the **marginal artery of Drummond**. From this marginal artery, straight vessels (also known as **vasa recta**) pass to the colon.

Variant anatomy

* replaced right hepatic artery
* accessory right hepatic artery
* replaced common hepatic artery
* replaced splenic artery
* replaced left gastric artery
* replaced dorsal pancreatic artery
* coeliaco-mesenteric trunk
* arc of Buhler persistence - arterio-arterial anastomosis with coeliac axis
* arc of Riolan - arterio-arterial anastomosis with IMA
Intracranial cavity (extra axial): Middle cranial fossa:Foramen spinosum

The**foramen spinosum** is located in the posteromedial part of greater wing of sphenoid (posterolateral to foramen ovale) and connects the middle cranial fossa with the infratemporal fossa. It transmits the middle meningeal artery, middle meningeal vein and meningeal branch of mandibular nerve.

Rarely, the middle meningeal artery originates directly from the ophthalmic artery, as a result foramen spinosum is either absent or small.
Abdomen:Visceral arteries:IMA

The **inferior mesenteric artery (IMA)** is an anterior branch of the abdominal aorta that supplies the hindgut. It is the smallest of the three anterior branches of the abdominal aorta. Supplies distal 1/3 of transverse colon to proximal rectum

Origin

* arises from the abdominal aorta anterior to the L3 vertebral body

Course

Initially, the inferior mesenteric artery descends anteriorly to the aorta and then passes to the left as it continues inferiorly.

Branches

* Left colic artery: supplies splenic flexure (distal transverse colon) and descending and sigmoid colon
* Sigmoidal arteries: two to four sigmoid arteries that supply sigmoid colon
* Superior rectal (hemorrhoidal) artery: Terminal branch of IMA; supplies proximal rectum
	+ Remainder of rectum is supplied by middle and inferior rectal arteries, which are small branches that arise from internal iliac arteries bilaterally
* Marginal artery of Drummond: Anastomotic artery coursing along mesenteric border of colon
	+ Immediately adjacent to colon; gives off vasa recta

Variant

* Double IMA
* Common colo-sigmoid trunk
* Absent left colic artery
* Common recto-sigmoid trunk
* Arise from left common iliac artery
* Variable branch numbers of sigmoid arteries
Bone: Bones of the Foot: Tarsal bones

7 articulating bones of the hind and midfoot:

Talus and calcaneus

Cuboid bone

* Roughly cuboidal shape
* 1 ossification center: Ossifies between 9th fetal month and 6 months age
* Articulates with calcaneus, navicular, 3rd cuneiform, 4th and 5th metatarsals, rarely head of talus
	+ Dorsal ligaments (calcaneocuboid, cubonavicular, cuneocuboid, cubometatarsal) strengthen each of these articulations
	+ Short and long plantar ligaments attach to plantar surface
* Sulcus at lateral margin, under which passes peroneus longus tendon
* 5th metatarsal base extends beyond lateral margin

Navicular bone

* Curved shape, concave proximally and convex distally
* 1 ossification center: Ossifies in 3rd year of life
* Articulates with talus, cuboid, cuneiforms
	+ Dorsal ligaments strengthen each of these articulations
	+ Single facet proximally for articulation with head of talus
	+ 3 facets distally for cuneiform articulations
	+ 1 facet laterally for articulation with cuboid
	+ Connected to anterior process of calcaneus by bifurcate ligament
	+ Connected to sustentaculum tali by spring ligament
* Large median eminence for attachment of posterior tibial tendon is located more plantar than main body of navicular

Cuneiform bones

* Wedge-shaped, with base of wedge at dorsal surface of 2nd and 3rd cuneiforms, dorsomedial surface 1st cuneiform
* In combination, form arch
* 1st cuneiform (medial cuneiform)
	+ Articulates with navicular, 2nd cuneiform, 1st metatarsal
	+ 1 or 2 ossifications centers: Ossify in 2nd year of life
* 2nd cuneiform (middle or intermediate cuneiform)
	+ Articulates with navicular, 1st and 3rd cuneiforms, 2nd metatarsal
	+ Smallest of cuneiforms
	+ 1 ossification center: Ossifies in 3rd year of life
* 3rd cuneiform (lateral cuneiform)
	+ Articulates with navicular, 2nd cuneiform, cuboid, 3rd metatarsal

Normal variant

* os trigonum – ossicle posterior to talus

* os peroneum – ossicle near to cuboid with in the peroneus longus

* accessory navicular – ossicle near navicular

* os vesalianum – ossicle at base of fifth metatarsal within peroneus brevis

* os intermetatarseum – ossicle between 1st and 2nd metatarsal
Infratemporal fossa:Pterygoid venous plexus

Pterygoid plexus - network of very small veins that lie around and within the lateral pterygoid muscle that drains the venous corresponding branches of the maxillary artery. Also received drainage of inferior ophthalmic vein via the inferior orbital fissure and the deep facial vein.

The plexus drain into the short maxillary vein through runs back to join the superficial temporal vein and form the retromandibular vein. The plexus is valved and act as a pump with the lateral pterygoid muscles to aid venous return.

Emissary veins connect the pterygoid plexus with the cavernus sinus via foramen lacerum and ovale.
Infratemporal fossa:Maxillary artery & branches

Maxillary artery is one out of the two terminal branches of the external carotid artery. it supplies the jaws, muscles of mastication, palate, nose and cranial dura mater.

Course:

1. the external carotid terminate behind the neck of the mandible giving off the maxillary artery
2. this passes forwards deep to the neck of the mandible between the neck and the sphenomandibular ligament into the infratemporal fossa. Here the auriculotemporal nerve lie above and the maxillary vein lie below it.
3. It is deep (sometimes superficial) to the lower head and passes forward and upwards between the two heads of the lateral pterygoid and into the pterygomaxillary fissure into the pterygopalatine fossa.
4. It then passes forwards with the maxillary nerve through the inferior orbital fissure into the orbit as the infraorbital artery

Three parts of maxillary artery.

Branches of 1st part of maxillary artery: before lateral pterygoid.

* **inferior alveolar artery:** pass downwards and forward toward the inferior alveolar nerve and all three enter the mandibular foramen. It passes forward in the mandible, supplying the pulps of the mandibular molar and premolar teeth and the body of the mandible.
* **middle meningeal artery:** pass vertically upwards through the foramen spinosum. It is embraced by two roots of the auriculotemporal nerve.
* **accessory meningeal artery:** passes upwards through the foramen ovale and supplies dura matter of the floor of the middle fossa and of the trigeminal cave.
* **Deep auricular and anterior tympanic artery:** the two arteries pass upwards and enter the ear superficial and deep to the tympanic membrane respectively. The deep auricular supplies the external acoutic meastus, passing between cartilage and bone. The anterior tympanic passes through the petrotympanic fissure to the middle ear to join the circular anastomosis around the tympanic membrane.

Branches of 2nd part: on lateral pterygoid.

* branches to the pyterygoid muscles (medial and lateral) and masseter, and deep temporal branches to temporalis
* branch to buccinator

Branches of 3rd part: after the lateral pterygioid within the pterygopalatine fossa. These accompany the branches of the maxillary nerve in the fossa of the same name.

* **infraorbital artery:** continues along the floor of the orbit and the infraorbital canal and merges with in the infraorbital nerve on the face.
* **sphenopalatine artery:** pass through the sphenopalatine foramen to enter the nasal cavity
* **posterior superior alveolar artery:** gives branches that accompany the corresponding nerves in the posterior wall of the maxilla
* **greater palatine artery:** this gives off lesser palatine branches to the soft palate and passes through the greater palatine foramen to supply the hard palate, tonsil, gums, and roof of mouth.
* pharyngeal artery
* artery of the pterygoid canal
Muscle/Group:Shoulder (Pectoral):Infraspinatus

**Infraspinatus muscle**

* Origin: Infraspinatus fossa of scapula
* Insertion: Middle facet greater tuberosity
* Nerve supply: Suprascapular nerve, distal fibers
* Blood supply: Suprascapular artery (branch of thyrocervical) and circumflex scapular branches of subscapular artery
* Action: External rotation of humerus and resists posterior subluxation
Anatomy

College documents

Skills and knowledge

Notes on normal variants

Anatomy Categories

Short notes essays

Anatomy of the Head & Face (Excluding CNS)

Anatomy of the Central Nervous System

Anatomy of the Neck (Non-Spinal)

Anatomy of the Upper Limb

Anatomy of the Lower Limb

Anatomy of the Spine & Back

Anatomy of the Thorax

Anatomy of the Abdomen

Anatomy of the Pelvis

Normal variants
Bone:Clavicle, scapula and humerus:Joint capsular attachments

CLAVICLE:

•Sternoclavicular joint: capsule and synovial membrane is attached around the margin of the articular surface at the bulbous sternal end of clavicle.

•Acromioclavicular joint: capsule and synovial membrane is attached to the margin of the articular surface and also covered by fibrocartilage.

HUMERUS:

The joint capsule of the humerus is attached to the articular margin except medially where it extended down the shaft to enclose the epiphyseal line.
Ligament:Pelvis:Sacroiliac ligaments

* **interosseous sacroiliac ligament:** from iliac tuberosity to the lateral mass of the sacrum; located posteriorly; thick and strong. Oriented superiorly & laterally. Weight transferred to sacrum, cause ligament to be pulled inward.
* **Anterior sacroliliac ligament:** flat band, joining bones above and below the pelvic brim.
* **Posterior sacroiliac ligament:** located superiorly to interosseous sacroiliac ligament. Posterior rami of spinal nerves and vessels pass between interosseous and posterior ligament.
* **Iliolumbar ligament:** a strong V shaped connective tissue which courses from the transverse process of L5 to iliac crest, and the front of the anterior sacroiliac ligament
* **Sacrotuberous:** Superior & inferior posterior iliac spines, sacrum & coccyx to ischial tuberosity
* **Sacrospinous:** Lateral sacrum & coccyx to ischial spine
Bone: Hip Bone, Femur, and Patella: Articular surfaces

Hip - the acetabulum is formed by all three hip bones, which join in a Y-shape. This surrounds the head of the femur on three sides, but is deficient inferiorly, called the acetabular notch. This is filled by the transverse acetabular ligament. The articulation is deepened by the acetabular labrum, which attaches circumferentially.

Femur - femoral head is ball shaped, slightly more than half a sphere, attached to the femoral neck. There is a medial depression, the fovea, where the ligamentum teres attaches the femur to the hip joint (and where the artery perforates)

Patella - see Articulations of the knee joint
Bone:Radius and ulna:Articular surfaces

RADIUS

Proximal articular surface:

the radial head and its circumference is covered by hyaline cartilage. The upper margin fits into the groove between the capitulum and the trochlea and enters the radial fossa in flexion. The circumference articulates with the ulnar and annular ligament.

Distal articular surface:

The radial styloid process projects beyond the ulna. The lateral part of the carpal articular surface articulates with the scaphoid and the medial part with the lunate.

ULNA

Proximal end:

The olecranon process and the coronoid process forms a concave facet for articulation with the humerus. This trochlear notch is a deeply saddle shaped surface between the olecranon and coronoid process. It is convex from side to side and concave from top to bottom. It fits the hour glass shaped trochlea as it spans over the surfaces of the olecranon and the coronod process.

The lateral surface of the coronoid process has a concave facet called the radial notch which is for articulation with the radial head. The annular ligament arises from the anterior and posterior margins of the notch.

Distal end:

The base of the ulna forms the head of the ulna and styloid process. The triangular fibrocartilage is attached by its apex to the base of the styloid process.
Basal CSF cisterns:Prepontine cistern

The **pontine cistern** (also known as the **prepontine cistern**) is one of the subarachnoid cisterns. It occupies a large space on the ventral aspect of the pons.

It is filled with CSF and is contiguous with the subarachnoid cavity of the spinal cord. It is also continuous with the cisterna magna behind, and the interpeduncular cistern anteriorly.

The CSF flows into it from lateral apertures (foramina of Luschka).

Content: basilar artery and its pontine and labyrinthine branches and the fifth to twelfth cranial nerve.
Meninges:Falx cerebri

The **falx cerebri** is the largest of the four main folds (or septa) of the intracranial dura mater, separating the cerebral hemispheres.

The falx cerebri is a double-fold of dura mater that descends through the interhemispheric fissure in the midline of the brain to separate the cerebral hemispheres.

The falx cerebri is relatively thin anteriorly where it attaches to the crista galli of the ethmoid bone, but is broader posteriorly where it attaches to the superior surface of the tentorium cerebelli inferiorly. It attaches superiorly to the midline of the cranium and extends posteriorly to attach to the the internal occipital protuberance.

Relations

* superior margin contains the superior sagittal sinus
* free edge between its attachments inferiorly closely related to the superior surface of the corpus callosum and contains the inferior sagittal sinus.
* straight sinus is included in the line of attachment between the falx cerebri and the tentorium cerebelli.
Joint:Shoulder joint:Labrum

The **glenoid labrum** is a fibrocartilaginous structure that attaches as a rim to the articular cartilage of the glenoid fossa and acts to deepen and increase the surface area. It acts as a static stabiliser of the glenohumeral joint, preventing dislocation and subluxation at the extremes of range of motion.

The glenoid labrum is approximately 4 mm thick and is round or triangular in cross section.

Attachments

The capsule of the glenohumeral joint attaches to the glenoid labrum. The glenoid labrum is continuous with:

* superiorly: tendon of the long head of biceps brachii
* anteriorly
	+ anterior band of the inferior glenohumeral ligament
	+ middle glenohumeral ligament (variably)

Blood and nerve supply

- see shoulder joint, via periosteal and capsular vessels.

Variant anatomy

* capsulolabral insertion classification
* anterior shoulder capsular insertion

* Buford complex
* sublabral foramen
* superior sublabral sulcus
Arterial:Femoral:Posterior tibial

The posterior tibial artery is the continuation of the popliteal artery in the lower leg and provides oxygenated blood to the posterior compartment of the leg and plantar surface of the foot. It is accompanied by the posterior tibial vein, along its course.

* origin: continuation of the popliteal artery
* main branches: fibular artery (peroneal)
* termination: medial and lateral plantar arteries

Course

Arises at lower border of popliteus, passes under arch of the soleus, runs down on TP and between FDL, FHL where it terminate into medial and lateral plantar arteries under the flexor retinaculum.

Branches

The main branch of the posterior tibial artery is the fibular artery (peroneal).  However, it also branches into:

* medial plantar artery
* lateral plantar artery
* Circumflex fibular (may arise from anterior tibial), runs laterally around neck of fibula
* Nutrient artery to tibia
* Muscular branches
Muscles:Deep fascia: Extensor retinacula

Aligns tendons of the anterior compartment of the leg as they traverse the ankle joint.

Two components - superior extensor retinacula at the superior part of the ankle joint, runs from medial tibia to medial fibula.

Inferior extensor retinacula - Y shaped, at the level of the ankle joint. Laterally runs from the talus, and forms two parts, the superior part extending to the medial malleolus, and the inferior part attaching to the plantar aponeurosis.

The structures running underneath are extensor hallucis longus, extensor digitorum longus, tibialis anterior, peroneus tertius, the deep branch of peroneal nerve and the anterior tibial artery (which becomes dorsalis pedis on passing under the superior extensor retinacula)
Meninges:Pia mater (in general)

The **pia mater** is the innermost layer of the meninges and together with the arachnoid mater is referred to as the **leptomeninges**. It invests the brain and the spinal cord and extend into the sulci.

Extent:

* Separated from the arachnoid mater by the CSF-filled subarachnoid space.
* It is prolonged out over the cranial nerves and spinal nerve roots to fuse with their epineurium.
* Invaginated into the substance of the brain by the entering cerebral arteries.

It is a highly vascular layer containing blood vessels that supply the underlying surface of the brain particularly over the cerebrum.

Perivascular spaces: pial-lined, interstitial fluid-filled structures that accompany vessels entering (penetrating arteries) or leaving (draining veins) cerebral cortex. Because the brain does not have a true lymphatic system this perivascular space is important in allowing the movement of substances back into the CSF.

* Accompany small, medium-sized arteries as they penetrate brain parenchyma

* Location:
	+ Around anterior commissure
	+ Inferior 1/3 of basal ganglia
	+ Anterior perforated substance
	+ Hemispheric white matter (centrum semiovale)
	+ Midbrain (around substantia nigra)

At certain points in the third, fourth and lateral ventricles the pia mater forms a double layer and is covered by ependymal cells and bulges into the ventricle to create the choroid plexus.
Infratemporal fossa:Pterygopalatine ganglion

The **pterygopalatine ganglion** is one of four parasympathetic ganglia of the head and neck and largest of the peripheral parasympathetic ganglia. It relay between the superior salivary nucleus in the pons and the lacrimal gland, and mucous and serous glands of the palate, nose and paransal sinuses. There are only parasympathetic cell bodies within the ganglion. The sensory communications with the maxillary nerve and sympathetic nerves pass through without relay.

* located in the pterygopalatine fossa
* anterior to opening of the pterygoid canal, below and medial to the foramen rotundum
* adjacent to the sphenopalatine foramen

Roots: mainly the nerve of the pterygoid canal (Vidian). It is formed by parasympathetic roots and sympathetic roots in the foramen lacerum, and sensory root from the maxillary nerve.

* Parasympathetic root:
	+ superior salivary nucleus via the greater petrosal nerve

* Sympathetic root:
	+ superior cervical ganglion via the internal carotid nerve through the deep petrosal nerve (foramen lacerum)

* Sensory root: trigeminal ganglion via the maxillary nerve

Branches: all branches of the pterygopalatine ganglion thus carries a mixture of sensory, secretemotor, and sympathetic fibres.

* **nasopalatine nerve:** pass through sphenopalatine foramen, and continue over and beyond the septum to the incisive canal to supply the anterior part of the hard palate.
* **medial posterior superior nasal nerve:** pass through the sphenopalatine foramen, cross the roof of the nose and distributed to the septum.
* **lateral posterior superior nasal nerve:** pass through sphenopalatine foramen and turn forward to supply the posterosuperior part of the lateral wall of the nose.
* **greater palatine nerve:** pass through the greater palatine canal, between perpendicular plate of the palatine bone and maxilla. It supplies the posterior part of the lateral wall of nose. At the greater palatine foramen, it turns forward to supple the mucous membrane of the hard palate
* **lesser palatine nerves:** two in number pass down behind the greater palatine nerve, through the lesser palatine foramen. Pass back to the soft palate and mucous membrane and palatine tonsil.
* **pharyngeal nerve:** supplies mucous membrane of the nasopharynx.

The postganglionic secremotor fibres to the lacrimal gland join the maxillary nerve, pass in its zygomatic branch to the orbit and join the lacrimal branch of the opthalmic nerve to reach the lacrimal gland.
Inner Ear

The **inner ear** refers to the bony labyrinth and its contents and the membranous labyrinth. It is divided into three sections:

* cochlea
* vestibule
* semicircular canals

Bony labyrinth: Bone that confines cochlear, vestibule, & semicircular canals

Perilymphatic spaces

* Perilymphatic spaces include area in vestibule surrounding utricle & saccule, in semicircular canals around semicircular ducts, and within scala tympani & vestibuli of cochlea
* Perilymph are fluid within bony labyrinth that "bathes" endolymph-containing membranous labyrinth structures

Membranous labyrinth/endolymphatic spaces

* Includes vestibule (utricle & saccule), semicircular ducts, scala media (cochlear duct), and endolymphatic duct & sac
* Endolymph = fluid within structures of membranous labyrinth

Cochlea: ~ 2 1/2 turns; modiolus; 3 spiral chambers (scala tympani, scala vestibuli, & scala media)

Semicircular canals: Superior (S), lateral (L), & posterior (P)

* Superior canals: Projects cephalad; bony ridge over SSCC in roof of petrous pyramid called arcuate eminence
* Lateral canal: Projects into middle ear with tympanic CN7 on underside
* Posterior canal: Projects posteriorly parallel to petrous ridge

* Petrous apex: Anteromedial to inner ear
	+ Pneumatized or nonpneumatized (marrow)
	+ CN6 passes over superior margin of medial PA

Intratemporal facial nerve

* CN7 segments: IAC, labyrinthine, tympanic, mastoid segments
* Geniculate ganglion = anterior genu
* Posterior genu: Tympanic segment bends inferiorly to become mastoid segment
* Stylomastoid foramen: CN7 exits skull base here

Petrous internal carotid artery: C2 segment

* ICA: Vertical & horizontal T-bone segments
* Vertical segment: Rises to genu beneath cochlea
* Horizontal segment: Projects anteromedially to turn cephalad as precavernous & cavernous ICA

Inner ear nerves

* Cochlear nerve: Afferent hearing fibers from bipolar spiral ganglion (which receives afferent information from organ of Corti) coalesce into cochlear nerve
* Superior vestibular nerve: Afferent balance fibers from utricle, superior SCC, & lateral SCC coalesce at superior vestibular ganglion into superior vestibular nerve
* Inferior vestibular nerve: Afferent balance fibers from saccule & posterior SCC coalesce at inferior vestibular ganglion into inferior vestibular nerve
Infratemporal fossa:Maxillary n. & branches

The **maxillary nerve** (CN V2) is one of the three branches or divisions of the trigeminal nerve, the fifth (V) cranial nerve.

It comprises the principal functions of sensation from the maxillary, nasal cavity, sinuses, the palate and subsequently that of the mid-face.

Course:

* It begins at the middle of the trigeminal ganglion and, passing horizontally forward, it leaves the skull through the foramen rotundum
* It then crosses the pterygopalatine fossa, inclines laterally on the back of the maxilla, and enters the orbit through the inferior orbital fissure.
* It traverses the infraorbital groove and canal in the floor of the orbit as the infra-orbital nerve and appears upon the face at the infraorbital foramen.
* At its termination, the nerve lies beneath the quadratus labii superioris, and divides into a leash of branches that spread out upon the side of the nose, the lower eyelid, and the upper lip, joining with filaments of the facial nerve.

Branches

Its branches may be divided into four groups, depending upon where they branch off: in the cranium, in the pterygopalatine fossa, in the infraorbital canal, or on the face.

* In the cranium
	+ **Middle meningeal nerve in the meninges**

* From the pterygopalatine fossa
	+ **Infraorbital nerve:** through Infraorbital canal
	+ **Zygomatic nerve (zygomaticotemporal nerve, zygomaticofacial nerve):** through Inferior orbital fissure
	+ **Posterior superior alveolar nerve:** through the pterygomaxillary fissure to the posterior wall of the maxilla. It divides into two or three branches. Distribute to molar teeth amd mucous membrane of the maxillary sinus.
	+ **Middle superior alveolar nerve**
	+ **Communication with pterygopalatine ganglion and its branches.**

* In the infraorbital canal: running now as the infraorbital nerve
	+ **Anterior superior alveolar nerve**

* On the face
	+ **Inferior palpebral nerve**
	+ **Superior labial nerve**
	+ **Lateral nasal nerve**
Deep DCF:“Danger space” and its significance

The **danger space** is a region of the neck in which infection in this space can spread directly to the mediastinum. There are also no midline raphe unlike the retropharyngeal space that is anterior to it, so infections can spread bilaterally.

Boundaries

* superiorly by the skull base
* anteriorly by the alar fascia (retropharyngeal space)
* posteriorly by the prevertebral fascia
* inferiorly level of the diaphragm.
Basal CSF cisterns:Interpeduncular cistern

The **interpeduncular cistern** (or **basal cistern**) is one of the subarachnoid cisterns. It lies between the dorsum sellae of the sphenoid and the cerebral peduncles.

* roof: floor of the third ventricle (mamillary bodies and posterior perforated substance)
* floor: dorsum sellae, formed by the arachnoid membrane passing across between the right and left temporal lobes.

Content: It contains the terminal branches of the basilar artery and the posterior part of the circle of Willis. More specificially:

1. The optic chiasm
2. The bifurcation of the basilar artery.
3. Peduncular segments of the posterior cerebral arteries (PCA).
4. Peduncular segments of the superior cerebellar arteries.
5. Perforating branches of the PCA.
6. The posterior communicating arteries (PCoA).
7. The basal vein of Rosenthal.
8. The third (III) cranial nerve, which passes between the posterior cerebral and superior cerebellar arteries.
Muscles:Anterior compartment of the thigh:Pectineus

The **pectineus muscle** is a flat, quadrangular muscle, situated at the anterior part of the upper and medial (inner) aspect of the thigh.

Origin: pectineal line of the pubis

Insertion: pass downward, backward, and lateral, to be inserted into the pectineal line of the femur which leads from the lesser trochanter to the linea aspera.

**Relations:**

The pectineus is in relation by its anterior surface with the pubic portion of the fascia lata.

By its posterior surface with the capsule of the hip joint, and with the obturator externus and adductor brevis, the obturator artery and vein being interposed.

By its lateral border with the psoas major, the femoral artery resting upon the line of interval.

By its medial border with the outer edge of the adductor longus.

**Innervations:**

Femoral nerve (L2 and L3) and occasionally (20% of the population) a branch of the obturator nerve called the accessory obturator nerve.
Joint:Elbow joint:Fibrous capsule & joint cavity

The capsule is attached to the humerus at the medial and lateral margins of the trochlea and capitulum.

* anteriorly, above the coronoid and radial fossae
* posteriorly, olecranon fossa
* distally, margins of the trochlear notch of the ulna and annular ligament of the proximal radioulnar joint
* NOT ATTACHED TO THE RADIUS.

The synovial membrane line the capsule and the lower part of the annular ligament, including the fossa on the lower end of the humerus.

LIGAMENT:

Ulnar collateral is triangular and has three bands.

* Anterior band is strongest. Passes from medial epiconydle to small tubcler on the medial border of of the coronoid process.
* Posterior band attaches to the tubercle and the medial border of the olecranon.
* Thin middle band runs directly between the anterior and posterior band. The ulnar nerve grooves this.

Radial collateral is a single triangular band.

* Attach from lateral epicondyle and base fuses with the annular ligament of the head of the radius.
* Anterior and posterior ligaments are thickened parts of the capsule.

Annular ligament: attached to the anterior and posterior margins of the radial notch of the ulna and wraps around the head/neck of the radius. It has no attachment to the radius and remains free to rotate in the annular ligament.
Joints:Knee Joint:Menisci (medial & lateral)

**Menisci:** intracapsular fibrocartilage structure within the knee joint that deepen the tibiofemoral articulation. Peripherally thickened and tapers to thin free edge centrally. Consists of a central body with anterior and posterior horns.

* Lateral meniscus: smaller and semicircular
	+ Uniform shape, minimally and gradually enlarging from anterior to posterior
* Medial meniscus: larger and semilunar (C-shaped)
	+ non-uniform shape: posterior horn much larger than anterior horn, with a small mid body.

Attachments:

* Osseous attachments: Both menisci are firmly attached to tibia at their roots
	+ LM roots: Located near center of tibial plateau with attachment only to the anterior and far posterior portion.
		- Anterior horn: attaches immediately lateral to origin of ACL
		- Posterior horn: attaches just posterior to ACL, and anterior to PCL
		- No attachment to the lateral collateral ligament and posteriorly, minimal capsular attachment due to popliteus tendon.
	+ MM roots: roots are located at center of tibial plateau, but more anteriorly and posteriorly for anterior horn and posterior horn, respectively than those of LM.
		- Anterior horn: MM anterior to origin of ACL
		- Posterior horn: MM immediately anterior to PCL
		- Capsular attachment: laterally to the third layer of the MCL, origin of the meniscofemoral and mesnicotibial ligament ligament.

Blood supply

* outer one-third: supply from the peripheral meniscal plexus, in turn formed from the medial, lateral and middle genicular arteries
* inner two-thirds: no vascular supply; diffusion dependent

Nerve supply

* posterior articular branch of the posterior tibial nerve and terminal obturator and femoral nerve branches

Variant anatomy

* Discoid meniscus
* Congenital hypoplasia or absence
* Aberrant insertion of anterior horn of medial menisci
	+ into ACL
	+ anterior margin of tibia
	+ no attachment and stabilized by transverse ligament
* Meniscal ossicle
* Oblique menisco-meniscal ligaments: Cross from anterior horn of one to posterior horn of other meniscus, passing between ACL and PCL
* Menisco-ACL ligament
Bone:Clavicle, scapula and humerus:Epiphyses – (sites, dates of appearance/fusion)

* Medially and laterally 5th week of life
* Sternal end during late teens and fuses rapidly.
* Ossification completes at 21-25 years of age.

Scapular ossification:

The scapula is ossified from 7 or more centers: one for the body, two for the coracoid process, two for the acromion, one for the vertebral border, and one for the inferior angle. Ossification of the body begins about the second month of fetal life, by an irregular plate of bone forming, immediately behind the glenoid cavity.

The scapular spine growing up from its dorsal surface about the third month. The larger part of the scapula undergoes membranous ossification. Some of the outer parts of the scapula are cartilaginous at birth, and would therefore undergo endochondral ossification.[7]

At birth, a large part of the scapula is osseous, but the glenoid cavity, the coracoid process, the acromion, the vertebral border and the inferior angle are cartilaginous. From the 15th to the 18th month after birth, ossification takes place in the following order

- Firstly in the root of the coracoid process

- Secondly, near the base of the acromion

- Thirdly, in the inferior angle

- Fourthly, near the outer end of the acromion

- Fifthly, in the medial border

Humeral ossification:

Total 8 centers.

Primary center appears in the center of the shaft at 8th week. Upper and lower ends are cartilaginous at birth.

Three secondary centers appear at the upper end for the head, greater and lesser tubercles in the first few years after birth which forms a single epiphysis. This fuses at 20 years.

Four secondary centers appear in the lower end. The trochlea, capitulum and lateral epicondyle for a single epiphysis and fuses at 15 years. The medial epicondyle is separate and fuses at 20 years,
Intracranial cavity (extra axial): Middle cranial fossa:Sphenoid body, greater wing & sinus

- Unpaired bone of the cranium, situated at the middle of the skull anterior to the temporal bones and basilar part of the occipital bone
- Forms the central part of the anterior and middle skull base
- Also one of the seven bones of the orbit

Gross anatomy:
- Butterfly shaped bone with extended wings
- Central body

```
      - sella turcica - houses the pituitary gland
      - paired sphenoid sinuses

```

- Greater wings project laterally from the body
- Lesser wings project anteriorly
- Pterygoid processes project inferiorly at the junction between the body and greater wings

Articulations:
- Articulates with 12 bones

```
      - Paired: temporal, parietal, palatine, zygomatic bones
      - Unpaired frontal, occipital, vomer, ethmoid bones

```

Features:
- Superior orbital fissure

```
      - Lacrimal branch of the ophthalmic nerve
      - Frontal branch of the ophthalmic nerve
      - Superior ophthalmic vein
      - Trochlear nerve
      - Superior division of oculomotor nerve
      - Nasociliary brach of ophthalmic nerve
      - Inferior division of oculomotor nerve
      - Abducens nerve

```

- Optic canal

```
      - V2
      - Ophthalmic artery

```

- Foramen ovale

```
      - V3 branch of CN V
      - Motor root of CN V
      - Accessory meningeal artery
      - Emissary vein
      - Lesser petrosal nerve

```

- Foramen rotundum

```
      - V2

```

- Foramen spinosum

```
      - Nervus spinosus
      - Middle meningeal artery
      - Middle meningeal vein

```

- Vidian canal

```
      - Pterygoid nerve
      - Pterygoid artery

```

- Foramen lacerum
- Carotid groove

Ossification
- Body and lesser wings of the sphenoid bone develop through classic endochondral ossification
- Pterygoid processes undergo intramembranous ossification
- Greater wings undergo both endochondral and intramembranous ossification
Arterial structure:Radial & Ulnar:Ulnar

**Ulnar artery** is the medial terminal branch of the brachial artery.

Course:

* Passes deep to the pronators teres and beneath the fibrous arch of the flexor digitorum superficialis
* Runs medially and distally on FDP with ulnar nerve to its medial side and passes down over the front of the wrist
* Lies in front of the flexor retinaculum and continues as superficial palmar arch

Branches:

* Anterior and posterior ulnar recurrent arteries: Form anastomosis around medial side of elbow with branches of brachial artery
* Common interosseous artery: Arises in distal aspect of cubital fossa
	+ Anterior interosseous artery: Runs distally on interosseous membrane. Pierces the membrane distally and ends in dorsal carpal arch
	+ Posterior interosseous artery: Enters posterior compartment proximal to interosseous membrane, between supinator and abductor pollicis longus. Runs between deep and superficial extensors. Supplies posterior muscles
* Muscular branches to medial side of forearm

* Dorsal carpal branch arises at pisiform, passes dorsally beneath FCU into dorsum of wrist, deep to extensor tendons, to anastomose with radial artery, dorsal carpal branch, to create dorsal carpal arch
* Deep palmar branch: arises at FR; passes medially through hypothenar muscles (AP & FDMB); turns lateral into palm to anastomose with radial artery, deep palmar branch, to form deep palmar arch
* Superficial palmar branch: continues distal superficial to FR to join radial artery, superficial branch, creating superficial palmar arch
Joints:Tibiofibular:Distal tibiofibular joint (Syndesmosis)

Fibrous joint between convex medial surface of distal fibula and concave fibular notch of the distal tibia.

Held by 4 tibiofibularsyndemostic ligaments.

* Anterior & posterior tibiofibular ligaments
	+ Extend obliquely between anterior & posterior tibial & fibular tubercles respectively
	+ Distal anterior tibiofibular ligament: Bassett ligament
* Inferior transverse ligament: Distal part of posterior tibiofibular ligament
* Interosseous ligament: Distal thickening of syndesmotic membrane
Intracranial cavity (extra axial): Anterior cranial fossa:Ethmoid bone

Forms part of the midline of the anterior cranial fossa. Anterior cranial fossa surface approx. 3 x 1.5cm. Surrounded anteriorly and laterally by the frontal bone, and posteriorly articulates with the lesser wing of the sphenoid and demarcates part of the junction between anterior and middle crania fossae.

Important structures
Foramen cecum (lit. blind ending passage) - anterior midline, formed in articulation of frontal and ethmoid bones. Often not patent. Contains nasal emissary veins, infection may track up into cranial base.

Crista galli (lit. cock's comb) - midline, superior projection, continuation of the frontal crest of the frontal bone. The anterior part of the falx cerebri attaches here.

Cribriform plate - numerous small foramina which perforate into the roof of the nasal cavity (medial to the ethmoid air cells).
The olfactory bulbs lie on top of the cribriform plate, one either side of the crista galli.
Cranial nerve systems:Oculomotor nerve & nucleus, ciliary ganglion

Occulomotor nerve is a mixed cranial nerve (motor and parasympathetic) from the midbrain governing eye movement and pupils constriction/dilation.

Origin

* **Oculomotor nuclear complex**
	+ Paired paramedian nuclear complex
		- Located in midbrain anterior (ventral) to cerebral aqueduct at level of superior colliculus
		- Partially embedded in periaqueductal gray matter
* **Edinger-Westphal parasympathetic nuclei**
	+ Located dorsal to oculomotor nuclear complex in poorly myelinated periaqueductal gray matter
	+ Preganglionic parasympathetic fibers exit nucleus, course ventrally with motor CN3 fibers
	+ Innervation of internal eye muscles (sphincter pupillae and ciliary muscles)

Intra-Axial Segment

* Oculomotor fascicles course anteriorly through medial longitudinal fasciculus, red nucleus, substantia nigra and medial cerebral peduncle. Exit midbrain into interpeduncular cistern

Cisternal Segment

* Courses anterolaterally through interpeduncular and prepontine cisterns
* Passes between posterior cerebral (PCA) and superior cerebellar arteries (SCA)
* Courses inferior to posterior communicating artery and medial to free edge of tentorium cerebelli
* Penetrates dura to enter roof of cavernous sinus

Cavernous Segment

* Enters roof of cavernous sinus surrounded by narrow oculomotor CSF cistern
* Courses anteriorly through lateral dural wall of cavernous sinus
* CN3 remains most cephalad of all cranial nerves within cavernous sinus
* CN3 superolateral to cavernous internal carotid artery

Extracranial Segment

* CN3 enters orbit through superior orbital fissure and passes through annulus tendineus (annulus of Zinn)
* Divides into superior and inferior branches
	+ Superior branch supplies levator palpebrae superioris (with sympathetic nerves picked up from the carotid artery) and superior rectus muscles
	+ Inferior branch supplies inferior rectus, medial rectus and inferior oblique muscles
* Preganglionic parasympathetic fibers follow inferior branch to ciliary ganglion of orbit
	+ Postganglionic parasympathetic fibers continue as short ciliary nerves to enter globe with optic nerve
	+ In globe short ciliary nerves to ciliary body and iris
	+ Control papillary sphincter function and accommodation via ciliary muscle.