Question 1 – Femur
Write short notes on the anatomy of the femur.
OVERVIEW
The only long bone in the thigh, serving as the site of origin for muscles and ligaments which move the hip and knee joint.
STRUCTURE
Head
– spherical, projects superomedially
Neck
– cylindrical strut, connects head to shaft at 125 degree angle
Greater trochanter
– lateral projection from shaft, attaches hip abductors and external rotators
Lesser trochanter
– posteromedial projection from shaft, attaches iliopsoas
Intertrochanteric line
– oblique line on anterior shaft, descends medially from greater torchanter
Shaft
– Descends medially at 7 degrees from vertical
– Middle third t
– Linea aspera: roughened ridge of bone on the posterior surface, which diverges superiorly as pectineal line and gluteal tuberosity and diverges inferiorly as medial and lateral supracondylar line
Medial and lateral condyles
– Rounded areas at the distal end of the femur, separated by the intercondylar fossa, form the articular surface with the menisci of the knee inferiorly and the patella anteriorly.
Medial and lateral epicondyles
– Bony elevations on the non-articular surface, attaches the medial and lateral collateral ligaments
ARTICULATIONS
Hip joint – head with lunate surface of acetabulum
Knee joint – condyles with menisci of tibia and patella
ATTACHMENTS
Muscles
– Greater trochanter: gluteus muscles (minimus, medius and maximus), external rotators (piriformis, obturator internus, gemellus superior and inferior), vastus lateralis
– Lesser trochanter: iliopsoas (iliacus, psoas major)
– Intertrochanteric crest: quadratus femoris
– Linea aspera: adductor muscles (longus, brevis, magnus), vastus lateralis, short head biceps femoris
– Lateral epicondyle: popliteus, plantaris
– Adductor tubercle: gastrocnemius (attaches behind)
Ligaments
– Iliofemoral, pubofemoral, ischiofemoral ligaments
– Medial and lateral collateral ligaments of the knee
– Anterior and posterior cruciate ligament
– Oblique popliteal ligament
– Meniscofemoral ligament
BLOOD SUPPLY
Femoral head: medial and lateral femoral circumflex arteries (branch of deep femoral artery), artery to ligamentum teres (branch of MFCA), genicular artery branches of ascending cervical
DEVELOPMENT
– Ossifies in cartilage
Question 2 – Clavicle
Write short notes on the anatomy of the joints of the clavicle.
Question 3 – Pectoral muscles
Write short notes on the anatomy of the pectoral muscles.
PECTORALIS MAJOR
– Large, fan-shaped superficial muscle of the pectoral region composed of a sternal and clavicular head.
– Attachment: distal attachment of both heads is the intertubercular sulcus of the humerus, clavicular head originates from the anterior surface of the medial clavicle, sternocostal head originates from the anterior surface of the sternum
– Function: adducts and medially rotates the upper limb and draws the scapula anteroinferiorly. The clavicular head acts individually to flex the upper limb
– Innervation: lateral (lateral cord of brachial plexus) and medial (medial cord of brachial plexus) pectoral nerves
– Blood supply: Pectoral branch of thoracoacromial, perforating branches of internal thoracic artery
PECTORALIS MINOR
– Thin, triangular muscle, situated at the upper part of the chest beneath the pectoralis major
– Origin: arises from the upper margins and outer surfaces of the 3rd/4th/5th ribs.
– Insertion: Medial border and upper surface of the coracoid process of the scapula
– Function: depresses the point of the shoulder, draws scapula anteroinferiorly.
– Thoracoacromial artery, superior thoracic, lateral thoracic
Question 4 – Levator ani
Write short notes on the anatomy of the levator ani.
GENERAL DESCRIPTION
The levator ani is a broad, thin muscle group situated on either side of the pelvis. Formed by three paired muscles: pubococcygeus, iliococcygeus, puborectalis.
ATTACHMENTS
Puborectalis
– Originates from both sides of the body of the pubis, and passes posteriorly to encircle the rectum and form a U-shaped sling around the anorectal junction
Pubococcygeus
– Main component of levator ani
– Originates from the body of pubis, lateral to the origin of the puborectalis muscle
– The fibres course around margin of urogenital hiatus posteriorly to attach to the tendinous centre of the perineum, anococcygeal body and coccyx.
Iliococcygeus
-Originates from the inner surface of the ischial spine and along tendinous arch (a thickened band of fascia covering the inner aspect of obturator internus muscle)
Posteriorly attaches to iliococcygeus of the opposite side in the midline to form anococcygeal raphe extending from anal aperture to coccyx.
SURFACE AND RELATIONS
NEUROVASCULAR SUPPLY
Blood supply
– Inferior gluteal artery
– Inferior vesical
– Pudendal
Innervation
– Innervated by nerve to levator ani, branches from ventral ramus of S4,
Also contributions from inferior rectal branch of pudendal nerve (S2-4)
ACTIONS
Puborectalis
Tonic contraction bends the canal anteriorly and forms a 90-degree anorectal angle at the anorectal junction to maintain faecal continence
Question 5 – Parotid gland
Write short notes on the anatomy of the parotid gland.
OVERVIEW
Bilateral salivary glands located on the side of the face. Produces and secretes serous saliva into the oral cavity via the parotid duct.
LOCATION
Parotid region
– Superiorly: zygomatic arch
– Inferiorly: inferior border of the mandible
– Anteriorly: masseter
– Posteriorly: external ear and sternocleidomastoid
The parotid duct arises from the anterior surface of the gland, traversing the anterior surface of the masseter and pierces the buccinator to open in the oral cavity near the second upper molar.
CONTENTS
– External carotid artery, bifurcating into two terminal branches; the maxillary artery (larger) and the superficial temporal
– Retromandibular vein, formed by the convergence of the superficial temporal and maxillary vein
– Facial nerve – five terminal branches: temporal, zygomatic, buccal, marginal mandibular, cervical
BLOOD SUPPLY
– posterior auricular (branch of ECA)
– superficial temporal (branch of ECA)
VENOUS DRAINAGE
– retromandibular vein
INNERVATION
– Sensory: auriculotemporal nerve and great auricular nerve
– Sympathetic: superior cervical ganglion
– Parasympathetic: glossopharyngeal nerve
Question 6 – Prostate gland
Write short notes on the anatomy of the prostate gland.
OVERVIEW
– walnut-sized accessory gland in the male reproductive system, secretes proteolytic enzymes into the semen constituting 30% of seminal fluid bulk.
POSITION
– Inferior to the neck of the bladder, superior to external urethral sphincter.
STRUCTURE
– formed by 70% glandular tissue/30% fibromuscular stromal tissue
– lateral lobes: lateral thirds of the gland, either side of the urethra
– middle third divided into 3 lobes
– Anterior lobe – anterior to urethra, between lateral lobes
– Median lobe – between anterior and posterior lobes, superior to ejaculatory ducts
– Posterior lobe – between lateral lobes, inferior and posterior to ejaculator ducts
SURFACES
– Base: upper surface against neck of bladder
– Apex: rests on the pelvic floor
– Anterior surface: connect to pubic body via puboprostatic ligaments and forms posterior wall of retropubic space
– Posterior surface: separated from rectum by Denonvillier fascia
– Inferolateral surface: rest on the levator ani
STRUCTURE
– Central – surrounds ejaculatory ducts, superior to peripheral zone
– Peripheral – surrounds distal prostatic urethra at the apex, extending posteriorly
– Transition – anterolateral to proximal urethra
– Anterior fibromuscularstroma
– Prostatic ducts: 10-12 openings at each side of the seminal colliculus open into the prostatic portion of the urethra
BLOOD SUPPLY
– prostatic branch of inferior vesical artery
VEIN DRAINAGE
– prostatic plexus laterally and posteriorly into internal iliac veins
INNERVATION
– prostatic nerve plexus, extension of inferior hypogastric plexus
– sympathethic: L1-L2
– parasympathetic: pelvic splanchnic nerve (S2 – S4)
LYMPHATIC DRAINAGE
– internal iliac and obturator nodes
RELATIONS
– anterior: pubic symphysis
– posterior: rectum
– superior: bladder
– inferior: urogenital diaphragm
– lateral: prostatic venous plexus and levator ani
VARIANTS
– prostate agenesis
– prostate hypoplasia
– prostate ectopica
– prostate artery variants (arise from internal pudendal, superior vesical, obturator
Question 7 – Hypoglossal nerve
Write short notes on the anatomy of the hypoglossal nerve (CN XII).
OVERVIEW
The twelfth paired cranial nerve, has a purely somatic motor functions
ORIGIN
From the hypoglossal nucleus, it arises as a number of small rootlets in the anterolateral sulcus, separating the olive and the pyramid, in the medulla oblongata of the brain stem
COURSE
– Passes laterally across the posterior cranial fossa, within the subarachnoid space
– exits the cranium via the hypoglossal canal of the occipital bone
– receives a branch of the cervical plexus that conducts fibres from C1/C2 spinal nerve roots which travel within its sheath
— it branches to innervate the geniohyoid and thyrohyoid
— also supplies the ansa cervicalis (loop of nerves which is part of the cervical plexus and innervates omohyoid, sternohyoid and sternothyroid muscles – depresses the hyoid bone)
– It then passes inferiorly to the angle of the mandible, emerging from behind the posterior belly of the diagastric muscle.
– It loops around a branch of the occipital artery and travels forward into the region behind the mandible
It crosses the internal and external carotid arteries, and moving in an anterior direction to enter the tongue.
SUPPLY
Extrinsic muscles of the tongue
– Genioglossus
– Hyoglossus
– Styloglossus
(Palatoglossus is innervated by vagus nerve)
Intrinsic muscle of the tongue
– Superior longitudinal
– Inferior longitudinal
– Transverse
– Vertical
VARIANTS
Question 8 – Diaphragmatic apertures
Write short notes on the anatomy of the diaphragmatic apertures.
CAVAL HIATUS
– quadrilateral in form, situated at the junction of the right and middle leaflets of the central tendon, at the level of T8
– transmits the inferior vena cava and occasionally branches of right phrenic nerve
– the walls of the IVC are adherent to the margins of the hiatus
OESOPHAGEAL HIATUS
– ellipitical shaped, situated in the muscular part of the diaphragm at level T10
– transmits oseophagus, oseophageal branches from left gastric artery and vein, right and left vagus nerves
AORTIC HIATUS
– situated slightly left of the midline and bound anteriorly by the crura and posteriorly by the first lumbar vertebra, approximately at the level of T12
– transmits the abdominal aorta, thoracic duct and azygos vein
LESSER DIAPHRAGRAMTIC APERTURES
– right crus of diaphragm (x 2): transmit the right greater and lesser splanchnic nerves. occasionally the azygos vein.
– left crus of diaphragm (x 3): transmit the left greater and lesser splanchnic nerves and hemiazygos
– medial arcuate ligament: sympathethic trunk
– lateral arcuate ligament: subcostal nerve and vessels
– left phrenic nerve pierces the dome of the left hemidiaphragm
Question 9 – Axillary artery
Write short notes on the anatomy of the axillary artery.
OVERVIEW
Major artery supplying the upper limb
ORIGIN
Continuation of the subclavian artery from inferior border of 1st rib
TERMINATION
Continues as brachial artery at lower border of teres major
COURSE
1st part: superior to pectoralis minor
– superior thoracic (runs anteriorly to supply pectoralis major and minor)
2nd part: posterior to pectoralis minor
– thoracoacromial (runs over pectoralis minor to pierce clavipectoral fascia and supply clavicle, deltoid, acromion and pectoralis muscle via its four branches)
– lateral thoracic (runs laterally along lower border of pectoralis minor to supply serratus anterior and both pectoralis muscle
3rd part: inferior to pectoralis minor
– subscapular (largest branch, runs along posterior wall of axilla, thoracodorsal branch supplies serratus anterior, circumflex scapular contributes to scapular anastomosis
– anterior humeral circumflex artery (supplies head of humerus, anastomoses with posterior circumflex artery around surfical neck)
– posterior humeral circumflex artery (passes through posterior wall of axilla, supplies deltoid, triceps brachii and glenohumeral joint.
RELATIONS
– axillary vein lies medial to artery
– 2nd part of axillary artery is reference for the cords of the brachial plexus (i.e. posterior cord is posterior to 2nd part of axillary artery)
VARIANTS
– high origin of the subscapular artery from 2nd part
– common trunk for subscapular artery and posterior circumflex humeral artery. Can arise from 2nd or 3rd part
– common trunk for subscapular artery and posterior circumflex humeral artery with the thoracodorsal artery originating directly from the axillary artery
– common trunk for subscapular artery, posterior circumflex humeral artery and deep brachial artery
– anomalous high division into radial and ulnar arteries
– absence of lateral thoracic artery (replaced by lateral perforating branches of the intercostal arteries)
– alar thoracic artery: supplies the fat, skin and lymph nodes of the axilla
Question 10 – Arterial supply of the spinal cord
Write short notes on the anatomy of the arterial supply of the spinal cord.
OVERVIEW
Formed by different vessels with extensive collateral supply and drainage
ORIGIN
– Predominantly supplied by three longitudinal arteries: single anterior spinal artery, paired posterior spinal artery.
– Reinforced by radicular or segmental medullary arteries which enter the vertebral canal via the intervertebral foramina and divided into anterior and posterior branches with variable anastomoses with the spinal arteries.
Anterior spinal artery formed by branches of the vertebral artery before they unite to form the basilary artery
– Supplies anterior two-thirds of the spinal cord
Paired posterior spinal artery arise mostly from PICA (sometimes vertebral artery)
– Supplies the posterior one-third of the spinal cord
COURSE & TERMINATION
– Anterior spinal artery arises from two small branches, arising bilaterally near the termination of the vertebral artery. The branches descends along the anterior aspect of the medulla oblongata, uniting at the foramen magnum to form a single trunk. The anterior spinal artery travels in the anterior median fissure, terminating as a slender twig on the filum terminale (S1 – S2)
– Posterior spinal artery descends posterior to the medulla, passing in front of the posterior roots of the spinal nerves. It is reinforced by segmental and radicular branches. It terminates around the point of the cauda equina
BRANCHES
The anterior and posterior spinal arteries are connected by pial anastomoses termed arterial vasocorona.
Radicular and segmental arteries contributing to supply include:
PICA, vertebral arteries, ascending cervical arteries, deep cervical arteries, posterior intercostal arteries, lumbar arteries, lateral sacral arteries. The dominant segmental artery of the lumbosacral cord segments is the artery of Adamkiewics, arising on the left sides between T9 and L2.
VARIANTS
– Variable origin of artery of Adamkiewicz: arises on the right side, arising from lumbar arteries at level of L1 – L2, intercostal arteries T5 – T8
– Duplicate anterior spinal arteries
– Single-origin anterior spinal artery from unilateral vertebral artery
– Single or duplicate anterior spinal arteries arising off vascular arcade between vertebral arteries
– Posterior spinal arteries arising from vertebral artery (25%) or PICA (75%)
Question 11 – Jugular veins
Write short notes on the anatomy of the jugular veins.
EXTERNAL JUGULAR VEIN
Description
– Major vein receiving blood from exterior cranium and deep parts of face and part of the scapular region.
– Formed by junction of the posterior division of retromandibular vein with posterior auricular vein
Origin
Within substance of the parotid gland, at level of angle of mandible
Course
– Descends obliquely across the surface of sternocleidomastoid, coursing from angle of mandible towards middle of clavicle
– In the subclavian triangle, it perforates the deep fascia and terminates in the subclavian vein, lateral to its junction with the internal jugular vein
Valves
– Upper valves: pair of valves located 4cm above the clavicle
– Lower valves: pair of valves located near union with the subclavian vein
There is a dilated portion between the two sets of paired valves termed the sinus.
Tributaries
– Occipital (occasionally)
– Posterior external jugular
– Transverse cervical
– Suprascapular
– Anterior jugular vein
Relations
– Anterior: platysma, superficial fascia, skin
– Posterior: investing layer of deep cervical fascia, sternocleidomastoid
Variants
Duplicate external jugular vein
INTERNAL JUGULAR VEIN
Description
A major vein returning deoxygenated blood from the brain, upper face and neck
Origin
Formed by the union of inferior petrosal and sigmoid venous sinus, forming the jugular bulb in the jugular foramen (formed by the petrous temporal bone and occipital bone).
Course
Descends in the carotid sheath with internal carotid artery, separated by the vagus nerve
Tributaries
– Inferior petrosal sinus drains blood from cavernous sinus to jugular bulb
– Sigmoid dural venous sinus formed by sigmoid sinus and superior petrosal sinus
– Pharyngeal veins
– Common facial vein formed by facial and retromandibubular vein
– Lingual vein formed by the sublingual, deep lingual and dorsal lingual vein
enters IJV near greater horn of hyoid
– Superior thyroid
– Middle thyroid
(Note: inferior thyroid vein drains into brachiocephalic vein directly)
Relations
surrounded by accompanying lymph nodes
relation to internal carotid artery C2: posteriorly
– C3: posterolaterally
– C4: laterally vagus nerve (CN X) always situated between the ICA and IJV
anteriorly (i.e. is crossed by these structures) upper third:
– spinal root of accessory nerve (CN XI)
– middle third: lower root of ansa cervicalis
– lower third: sternocleidomastoid muscle, tendon of omohyoid muscle
posteriorly (from superior to inferior as the IJV descends in the neck) lateral mass of C1 (atlas)
– middle scalene muscle
– anterior scalene muscle
– pleura of lung apices
Question 12 – Inferior vena cava
Write short notes on the anatomy of the inferior vena cava
OVERVIEW
Large, retroperitoneal vein returning deoxygnated blood from abdominal, pelvic and lower limb structures to the right atrium
ORIGIN
Union of left and right iliac veins at the level of L5
COURSE
– Ascends in the retroperitoneal cavity, slightly right of the midline.
– Pierces the central tendon of the left diaphragm (caval hiatus) at level of T8, together with the right phrenic nerve
– Passes through pericardium before entering the inferior right atrium
TRIBUTARIES
T8: paired inferior phrenic veins
T8: 3 hepatic veins
L1: right suprarenal vein
L1: paired renal veins
L2: right gonadal vein
L1-L5: lumbar veins
L5: common iliac veins
RELATIONS
– Anteriorly: right common iliac artery, right gonadal vessels, duodenum D1 and D3 (D2 is anterolateral), head of pancreas
– Posterior: transversalis fascia, lower lumbar vertebrae, right psoas muscle, sympathetic trunk.
– Right: right kidney, duodenum D2, liver, right ureter
– Left: abdominal aorta, right crus
VARIANTS
– Duplicate IVC
– Azygos continuation of IVC
– IVC webs
– Left-sided IVC
– circumcaval ureter
Question 13 – Lymphatic drainage of the breast
Write short notes on the anatomy of the lymphatic drainage of the breast.
Question 14 – Basal Cisterns
Write short notes on the anatomy of the basal cisterns.
Question 15 – Popliteal fossa
Write short notes on the anatomy of the popliteal fossa.
GENERAL
A diamond-shaped area on the posterior aspect of knee that allows passage of neurovascular contents to the lower limb.
BOUNDARIES
– Superomedial: semimembranosus (tendon of semitendinosus superficially)
– Superolateral: biceps femoris
– Inferomedial: medial head of gastrocnemius
– Inferolateral: lateral head of gastrocnemius and plantaris
– Floor: posterior surface of knee joint capsule, popliteus muscle
– Roof: popliteal fascia (continuous with fascia lata of the leg), skin
CONTENTS
Medial to lateral
– Popliteal artery (continuation of femoral artery as it enters the posterior compartment of the thigh through an opening in the adductor magnus called the adductor hiatus).
– Popliteal vein (drains into femoral vein after it enters adductor hiatus)
– Sciatic nerve bifurcates at the apex into:
– Tibial nerve
– Common peroneal nerve (follows biceps femoris tendon)
Also contains:
– Fat
– Popliteal lymph nodes (drains into the deep and superficial inguinal lymph nodes)
RELATIONS
– Tibial and common peroneal nerve most superificial
– Popliteal artery deepest structure
VARIANTS
– High origin of the popliteal vein from two or three tributaries
– True duplication of the popliteal vein
– Persistent sciatic vein accompanying and anastomosing with the popliteal vein. Posterior view of the right lower limb.