Questions 1 – Cerebral Cortex
Write short notes on the anatomy of the Cerebral cortex excluding blood supply.
GENERAL
Outer layer of neural tissue of the cerebrum.
GROSS ANATOMY
Features folds termed gyri (gyrus singular) and grooves termed sulci (sulcus singular).
– Gyri and sulci increase surface area
– The larger sulci and gyri mark the division of the cortex of the cerebrum into lobes of the brain
– Frontal lobe: prospective memory, speech and language, personality, decision making, movement control
– Parietal lobe: sensorimotor planning, learning, language, spatial recognition
– Temporal lobe
– Occipital lobe
Sensory areas
– receive sensory information from the contralateral side of the body
– cortex that receives sensory inputs from the thalamus are termed primary sensory areas
– vision: primary visual cortex
– hearing: primary auditory cortex
– touch: primary somatosensory cortex
Motor areas
– located in both hemispheres
– voluntary movements: primary motor cortex
– select voluntary movements: supplementary motor areas and premotor cortex
BLOOD SUPPLY
– Cerebral arteries: anterior, middle and posterior – supply the cerebrum
ACA
– supplies anterior portions of the brain including most of frontal lobe
– branch of the circle of Willis, anastomose anteriorly via the anterior communicating artery
– 5 segments (A1 – A5)
– variants:
MCA
– arises from the internal carotid artery
– supplies majority of the lateral surface of hemisphere except for superior portion of parietal lobe (which is supplied by ACA) and inferior portion of temporal lobe and occipital lobe (which is supplied by PCA)
– 4 segments (M1 – M4: sphenoidal, insular, opercular, cortical)
– variants:
PCA
– arise from the basilary artery
– supplies the occipital lobes and inferior portion of temporal lobes
– 4 segments (P1 – P4: pre-communicating, post-communicating, quadrigeminal segment, cortical segment)
– variants: foetal origin of PCA, PCA fenestration, duplicated PCA
Question 2 – Dural venous sinus
Write short notes on the anatomy of the Dural venous sinuses.
GENERAL
Veins draining the cerebrum do not follow the same course as the arteries that supply it
Venous sinuses are large, low pressure veins within the folds of the fibrous dura mater and endosteum (except the sagittal and straight which are between two folds of dura mater).
11 – venous sinuses
SUPERIOR SAGITTAL SINUS
– commences anteriorly at foramen cecum
– receives emissary veins, superior cerebral veins and CSF draining through arachnoid granulations
– courses in the midline to the internal occipital protuberance to the drain into the confluence of sinuses which is on either side (usually the right)
– continues as the transverse sinus
INFERIOR SAGITTAL SINUS
– runs in the lower edge of the falx cerebri, join posteriorly with the cerebral vein to become the straight sinus
STRAIGHT SINUS
– runs in the tentorium between two folds of fibrous dura to the confluence of sinuses, where the falx is attached to the internal occipital protuberance
TRANSVERSE AND SIGMOID SINUS
– runs right and left from the confluence of sinuses to the mastoid bone, where they turn interiorly and become the sigmoid sinus
– Sigmoid descends to the jugular foramen as the internal jugular vein
SUPERIOR PETROSAL SINUS
– runs from the cavernous sinus to the sigmoid sinus in the attached margin of the tentorium on the superior border of the petrous part of the temporal bone
INFERIOR PETROSAL SINUS
– runs from the cavernous sinus to the internal jugular vein at the base of the petrous temporal bone
SPHENOPARIETAL SINUS
– runs along the free edge of the lesser wing of the sphenoid bone to the cavernous sinus
Question 3 – Oculomotor nerve
Write short notes on the anatomy of the Oculomotor nerve.
GENERAL
The third cranial nerve, carrying motor and parasympathetic innervation to structures within the bony orbit.
ORIGIN
– Oculomotor nucleus: at the level of the superior colliculus in the midbrain
– Edinger-Westphal nucleus: supplies parasympathetic fibres to the eye via ciliary ganglion
COURSE
– Originates from oculomotor and E.W. nuclei at the posteromedial aspect of the midbrain, the fibres exit the anterior surface of the brainstem, covered in pia mater
– Pass through the red nucleus, then substantia nigra exiting through the interpeduncular fossa
– Passes between the posterior cerebral artery superiorly and superior cerebella artery inferiorly
– Piereces the dura mater
– Traverses the cavernous sinus superior to the orbital nerves, receiving sympathetic branches from the internal carotid plexus
– Enter the orbit via the superior orbital fissure with
– Divides into the superior and inferior branch
BRANCHES
Superior Division
Runs forward above the optic nerve
Provides motor innervation to the superior rectus, levator palpebrae superioris
Inferior Division
Larger than the superior division. Further divides into three branches.
Provides motor innervation to the inferior rectus, medial rectus, inferior oblique
Supplies pre-ganglionic parasympathetic fibres to the ciliary ganglion, which innervates the sphincter pupillae and ciliary muscles
Question 4 – Parapharyngeal space
Write short notes on the anatomy of the Parapharyngeal space.
GENERAL
Deep compartment of the head and neck
GROSS ANATOMY
Shaped as an inverted pyramid, with base at the skull base and apex pointing inferiorly towards the greater cornu of the hyoid bone
BOUNDARIES
– Superior: base of skull
– Inferior: greater cornu of the hyoid bone
– Medial: middle layer of the deep cervical fascia covering the pharygneal constrictor, levator and tensor veli palatini muscles
– Lateral: superificial layer of the deep cervical fascia extending between styloid process and mandibular ramu
– Anterior: pterygomandibular raphe and superficial layer of the deep cervical fascia covering the medial pterygoid muscle
– Posterior: extension of the tensor palatini muscle fascia
CONTENTS
– Fat (main component)
– Internal maxillary artery
– ascending pharyngeal
– pterygoid venous plexus
– small branch of mandibular division of trigeminal nerve supplying tensor veli palatini
– salivary tissue
RELATIONS
– posteromedial to the masticator space, particularly medial pterygoid muscle
– anteromedial to the parotid space
– posterolateral to the pharyngeal mucosal space
– anterolateral to the prevertebral space, retropharyngeal space, and danger space
– anterior to the carotid (poststyloid parapharyngeal) space
– overlaps with the infratemporal fossa
Question 5 – Spinal meninges
Write short notes on the anatomy of the Spinal meninges and associated spaces.
GENERAL
Three membranes surround the spinal cord: dura mater, arachnoid mater and pia mater. They contain CSF, which act to support and protect the spinal cord. Distally the meninges form a strand of fibrous tissue termed the filum terminale which attaches to the coccyx, serving as an anchor.
DURA MATER
– Most external of the meninges
– Extends from the foramen magnum to the filum terminale, separated from the walls of the vertebral canal by the epidural space
– The dura mater surrounds the spinal nerve roots as they exit the vertebral canal and fuses with the epineurium (outer connective tissue of the nerve).
EPIDURAL SPACE
– Contains loose connective tissue, fat, spinal nerve roots below S2 and the internal vertebral venous plexus
– The vertebral venous plexus is a highly anastomotic network of valveless veins runnings from the foramen magnum to sacral hiatus. The anterior internal plexus lies on the posterior surface of the vertebral body. The posterior internal plexus lie on either side of the midline, in front of the vertebral arches and ligamenta flava. The internal plexus anastomose with the external vertebral venous plexus.
ARACHNOID MATER
– Delicate membrane, located between the dura mater and the pia mater
– It is separated from the latter by the subarachnoid space, which contains cerebrospinal fluid.
SUBARACHNOID SPACE
– contains arachnoid trabeculae, CSF
– arteries: radicular, segmental medullary and spinal
– Distal to the conus medullaris (L1 – L2), the subarachnoid space expands, forming the lumbar cistern
PIA MATER
– innermost of the meninges, thin membrane that covers the spinal cord, nerve roots and their blood vessels
– inferiorly fuses with the filum terminale
– Between the nerve roots, thickens to form the denticulate ligaments which attach to the dura mater to suspend the spinal cord in the vertebral canal
Question 6 – Left subclavian artery
Write short notes on the anatomy of the Left subclavian artery.
ORIGIN
Arises as the third major branch of the aortic arch
COURSE
Ascends in the superior mediastinum, entering root of neck posterior to the left sternoclavicular joint
Arches laterally in a groove on the superior surface of the first rib, posterior to the subclavian vein, separated from it by scalenus anterior muscle
TERMINATION
Terminates and continues as axillary artery between the clavicle and the lateral border of the first rib
PARTS
First part
Origin: to medial border of scalenus anterior
Relations: Anteriorly: vagus nerve, internal jugular
Branches:
– Vertebral artery
– Internal thoracic artery: gives of musculophrenic artery and superior epigastric artery
– Thyrocervical trunk: gives inferior thyroid, suprascapular, transverse cervical, ascending cervical
– Costocervical trunk: deep cervical and superior intercostal artery
Second part
Posterior to scalenus anterior
Relations: Anteriorly: anterior scalene muscle, subclavian vein
Posteriorly: scalenus medius
Superiorly: three cervical trunks of brachial plexus
Inferiorly: pleura
Branches: Costocervical trunk
Third part
Lateral border of scalenus anterior to lateral border of first rib
Branches: Dorsal scapular artery (Variants)
Relations: Inferiorly: first rib
VARIANTS
Aberrant right subclavian – originating distal to left subclavian, courses posterior to trachea and oesophagus to the right
Aberrant left subclavian artery – from right-sided aortic arch
Left vertebral artery originating from aortic arch
Dorsal scapular artery originating from 3rd part of subclavian artery
Dorsal scapular artery originating from 2nd part of subclavian artery
Question 7 – Venous drainage of the heart
Write short notes on the anatomy of the Venous drainage of the heart.
GENERAL
The coronary veins accompany the coronary arteries and eventually coalesce to form the coronary sinus which drains indirectly into the right atrium
GREAT CARDIAC VEIN
Origin: cardiac apex, anterior surface of heart
Course: ascends through the anterior interventricular sulcus with the anterior interventricular artery, then turn lefts into the atrioventricular groove.
Tributaries: receives left marginal vein and other veins draining both ventricles and left atrium.
Termination: empties into the coronary sinus
Relations: associated with the anterior interventricular artery
MIDDLE CARDIAC VEIN
Origin: cardiac apex, inferior surface of heart
Course: travels in the posterior interventricular sulcus towards base of the heart
Drainage: septum, diaphragmatic surface of LV and RV
Termination: empties into the coronary sinus
SMALL CARDIAC VEIN
Origin: inferior border of the heart in coronary sinus
Course: posterior atrioventricular sulcus
POSTERIOR CARDIAC VEIN
Origin: posterior surface of left ventricle
Course: ascends posterior wall
Joins coronary sinus
Drainage: posterior and diaphragmatic surface of LV
CORONARY SINUS
Origin: Union of oblique vein of left atrium and great cardiac vein at base of heart
Course: short course towards right atrium, receives great, middle and small cardiac veins, posterior vein of left ventricle and oblique of left atrium
Termination: enters the posterior inferior wall of right atrium, between IVC and septal leaflet of tricuspid valve, marked by Thebesian valve
VARIANTS
– Left sided IVC (fetal origin of the oblique vein of left atrium) may drain into coronary sinus
– Absent oblique vein of left atrium
– Absent small cardiac vein
– Absent posterior cardiac vein
– Absent left marginal vein
– Absent right marginal vein
– GCV draining into azygos vein
– GCV draining into SVC
Question 8 – Spleen
Write short notes on the anatomy of the Spleen.
GENERAL OVERVIEW
The largest lymphatic organ, located in the left upper abdominal quadrant. It plays a role in immune surveillance, proliferation and maturation of lymphocytes, degradation of senescent and damaged erythrocyte
STRUCTURE
Fist-sized organ, wrapped by a fibroelastic capsule. Covered by visceral pertioneum (except the splenic hilum)
SURFACES
– Diaphragmatic surface: adjacent to the diaphragm, slightly convexed and had impressions from ribs 9-12
– Medial surface: impressions from left colix flexure, stomach and left kidney. centrally contains the splenic hilum
CONNECTIONS
– Gastrosplenic ligament: connects anterior to the hilum to the greater curvature of stomach. Contains the short gastric and left gastroepiploic arteries.
– Splenorenal ligament: connects posterior to the hilum to left kidney. Contains the splenic vessels and tail of pancreas.
– Phrenicocolic ligament
– Greater omentum – connects to the stomach and kidney – a double fold of peritoneum that originates from the stomach
INNERVATION
Sympathethic: Splenic plexus, part of the coeliac plexus.
Parasympathetic: Vagal trunk
BLOOD SUPPLY/DRAINAGE
Splenic artery – highly tortuous branch of the coeliac trunk at T12, courses along body and tail of the pancreas
Splenic vein – closely related to splenic artery, drains into hepatic portal vein
LYMPHATIC DRAINAGE
Lymphatic vessels of the spleen follow the splenic vessels mentioned above and drain into the pancreaticosplenic lymph nodes, and ulimately the coelic nodes.
RELATIONS
Anterior: stomach
Medial: left kidney
Superior: diaphragm, left 9th to 11th ribs
Inferior: left colic flexure (splenic flexure)
VARIANTS
– Splenunculus – accessory spleen
– Wandering spleen
– Polysplenia
– Asplenia
– Splenogonadal fusion
– Retrorenal spleen
– Splenic cleft
Question 9 – Arterial supply of the anterior abdominal wall
Write short notes on the anatomy of the Arterial supply of the anterior abdominal wall.
GENERAL OVERVIEW
The anterior abdominal wall surrounds the anterolateral aspect of the abdominal cavity. The layers include
– Skin
– Superficial fascia (subcutaenous tissue, Camper’s fascia, Scarpa’s fascia)
– Muscle
– Fascia
– Parietal peritoneum
ARTERIAL SUPPLY
– Superior epigastric artery – branch of internal thoracic, which descends parasternal from the 1st part of subclavian artery. Branches of superior epigastric artery perforate the rectus sheath and supply the skin of the abdomen.
Provides an important alternate blood supply of the aorta becomes occluded
– Inferior epigastric artery – arises from external iliac artery and ascends with the inferior epigastric vein to eventually anastomoses with superior epigastric artery above the umbilicus. It forms the lateral border of Hesselbach’s triangle.
As it ascends, it courses between the rectus abdominis muscle and the posterior lamella of its sheath. The vas deferens as it leaves the spermatic cord in the male, and the round ligament of the uterus in the female, winds around the lateral and posterior aspects of the artery.
Question 10 – Sacrum
Write short notes on the anatomy of the Sacrum.
OVERVIEW
Large, thick bone with an inverted triangular shape located at the terminal vertebral canal, forming the posterior aspect of the pelvis. Formed by the fusion of 5 sacral vertebrae.
GROSS ANATOMY
Base: articulates with 5th lumbar vertebra via intevertebral disc
Apex: articulates with coccyx
Dorsal surface: convex
Anterior surface: convex
Auricular surface: lateral outer-ear shaped surface articulating with ilium
Central canal: contained within core of sacrum
Posterior sacral foramina: allows passage of nerves from central canal
SURFACE
Dorsal surface
– rough, coarse surface marked by 3 bony ridges/crest
– median sacral crest: formed by the fusion of the spinous process of first 3 vertebrae. Gives attachement for supraspinous ligament
– intermediate sacral crest: formed by fusion of the articular processes. Gives attachment for posterior sacroiliac ligaments
– lateral sacral crest: formed by fusion of the transverse process. Gives attachment for the sacrotuberous ligament and posterior sacroiliac ligaments
Pelvic surface
– concave
– anterosuperiorly has a bony projection termed the sacral promontory. Marks the superior border of the pelvis inlet.
– four transverse lines – remnants of fused sacral intervertebral discs
MUSCULAR
Anterior surface
– piriformis: originates from S2-S4 level of pelvic surface, externally rotates abducts, extends and stabilises hip joint
– coccygeus: inserts on lower sacrum, supports pelvic contents and flexes the coccyx
– iliacus: primarily arises on iliac fossa but also originates from ala of sacrum. Distally attaches to the lesser trochanter of the femur as the iliopsoas (combines with psoas muscle)
Posterior surface
– multifidus lumborum: deepest muscle, stabilises the spine. Attaches to the transverse processes
– erector spinae: helps extend/laterally bend head and vertebral column. Partly arises from the posterior sacrum and sacrospinous ligament
NEUROVASCULAR RELATIONS
– Central canal contains sacral fibres of the cauda equina
– Filum terminale is joined by arachnoid and dura mater at S@ and continues inferiorly as the coccygeal ligament which attaches to coccyx
– Has two sympathethic trunks running along pelvic surface of sacrum
– Medial sacral artery – continuation of abdominal aorta arising before it bifurcates. Runs in the midline of coccyx supplying posterior rectum, glomus coccygeum. Anastomoses with the lateral sacral arteries.
– Lateral sacral artery – a branch of the posterior division of internal iliac artery. Supplies meninges, sacrum and surrounding muscles
VARIANTS
– angel-wing sacrum.
– accessory sacroiliac joints.
– complete agenesis of the dorsal wall of the sacral canal
– developmental defects in the ala of the sacrum.
– developmental absence of a portion of the right ala of S1.
– Midline cleft of S1.
– sacral ribs.
– spina bifida occulta of S1.
Question 11 – Rectum
Write short notes on the anatomy of the Rectum.
GENERAL
Most distal segment of the large bowel, acts as a reservoir for faeces
POSITION
Midline, retroperitoneal organ of pelvis
ORIGIN
Continuous above with sigmoid colon at level S3. Macroscopically distinct from colon with absence of taenia coli, haustra and omental appendages.
COURSE
– Descends, following the sacral flexure – the anteroposterior curvature of the sacrum, with concavity anteriorly
– Three lateral curvatures (superior, intermediate and inferior), formed by the transverse folds of the internal rectum wall
– Final segment of the rectum dilated, termed the ampulla
BLOODY SUPPLY
Superior rectal artery – terminal continuation of inferior mesenteric artery, supplies superior two thirds
Middle rectal artery – branch of internal iliac artery, supplies part of inferior third
Inferior rectal artery – branch of internal pudendal artery, supplies part of inferior third
NERVE SUPPLY
Inferior mesenteric plexus (superior) and superior/inferior hypogastric (inferior)
Sympathetic: L1-L2
Parasympathetic: Pelvic splanchnic nerves (S2-S4)
VARIANTS
Middle rectal artery may be absent
Middle rectal artery arise from internal pudendal
Middle rectal artery arise from inferior gluteal
Question 12 – Radioulnar joint and triangular fibrocartilage complex
Write short notes on the anatomy of the Distal radioulnar joint and triangular fibrocartilage complex.
OVERVIEW
There are two radioulnar joints. The distal radioulnar joint is a pivot joint, enclosed within a fibrous capsule, located proximal to the wrist joint. It is an articulation between the ulnar notch of the radius and ulnar head.
LIGAMENTS
Triangular fibrocartilage complex is a biconcave ligamentous complex that stabilises and cushions the joints of the wrist. Consists of:
– articular disc attached to the lateral surface of the styloid process of ulnar with base anchored to the inferior margin of the ulnar notch of radius
– dorsal and palmar radioulnar ligaments: these are thickenings of the dorsal and palmar parts of the complex
– ulnar collateral ligament, ulnolunate and ulnotriquetral ligaments joint the complex on the ulnar attachment
– base of extensor carpi ulnaris sheath fuses with the dorsal margin of the complex
INNERVATION
Anterior and posterior interosseous nerves
BLOOD SUPPLY
Anterior interosseous, posterior interosseous and ulnar arteries
ACTIONS
– Pronation: Produced by the pronator quadratus and pronator teres
– Supination: Produced by the supinator and biceps brachii (musculocutaneous nerve)
RELATIONS
Proximally: Interosseous Membrane: sheet of connective tissue joining at the medial radial border to the lateral ulna border. Spans the distance between the two bones.
VARIANTS
Question 13 – Musculocutaneous nerve
Write short notes on the anatomy of the Musculocutaneous nerve.
OVERVIEW
Terminal branch of the brachial plexus of the lateral cord (roots C5 – C7), innervating muscles of the anterior compartment of the arm.
ORIGIN
Emerges at the inferior border of the pectoralis minor muscle
COURSE & RELATIONS
– As it leaves the axilla and pierces the coracobrachialis muscle near its point of insertion on the humerus
– Descends along the flexor compartment of the upper arm, between brachialis (deep) and biceps brachii (superficially)
– Pierces the deep fascia lateral biceps brachii to emerge lateral to the biceps tendon and brachioradialis
TERMINATION
Continues into forearm as the lateral cutaneous nerve (provides sensory innervation to lateral forearm)
BRANCHES & SUPPLY
– Coracobrachialis muscle
– Brachialis
– Biceps brachii
MOTOR FUNCTION
Flexes the upper arm at the shoulder and elbow.
SENSORY FUNCTION
Anterolateral innervation of skin via the lateral cutaneous nerve of the forearm.
VARIANTS
Passes under coracobrachialis (as opposed to through it)
Passed through biceps brachii
Exchange fibres with the median nerve
Question 14 – Gluteal muscles
Write short notes on the anatomy of the Gluteal muscles.
OVERVIEW
A gluteal region in the posterior pelvic girdle, at the proximal end of the femur.
MUSCLES, NEUROVASCULAR SUPPLY & ACTION
Superficial muscles: gluteal maximus/minimus/medius and tensor fascia lata
Gluteus maximus
– largest and most superficial gluteal muscle, produces the shape of the buttocks
– originates from posterior surface of ilium, sacrum and coccyx
– courses across the buttock region at 45-degree angle, then inserts into the iliotibial tract and gluteal tuberosity of the femur
– main extensors of the thigh, assists with lateral rotation
– innervated by inferior gluteal nerve
Gluteus medius
– fan-shaped muscle between the gluteal maximus and minimus
– originates from gluteal surface of the ilium and inserts into the lateral surface of the greater trochanter
– abducts and medially rotates
– innervated by superior gluteal nerve
Gluteus minimus
– deep smallest of the gluteal muscle. Similar the gluteus medius.
– originates from the ilium and converges to form tendon which inserts on the anterior side of the greater trochanter
– abducts and medially rotates the lower limb
– innervated by superior gluteal nerve
Tensor fascia lata
– small superficial muscle
– originates from the anterior superior iliac spine and inserts into the iliotibial tract.
– assists the gluteus medius and minimum is abduction and medial rotation
– innervated by superior gluteal nerve
Deep muscles: muscles underneath the gluteus minimus: piriformis, obturator internus, superior and inferior gemelli, quadratus femoris
Piriformis
– originates from anterior surface of sacrum and travels through the greater sciatic foramen to insert into the greater trochanter of femur
– laterally abducts and abduction
– innervated by nerve to piriformis
Obturator internus
– originates from the pubis and ischium at the obturator foramen and travels through the lesser sciatic foramen to insert into the greater trochanter of the femur
– lateral rotation and abduction
– innervated by nerve to obturator internus
Superior and inferior gemelli
– two narrow and triangular muscles separated by the obturator internus tendon
– superior originates from the ischial spine and inferior from the ischial tuberosity, and both attach to the greater trochanter
– lateral rotation and abduction
– superior innervated by nerve to obturator internus and inferior innervated by nerve to quadratus femoris
Quadratus femoris
– flat square-shaped muscle, most inferior of the muscles
– originates from the lateral side of the ischial tuberosity and attaches to the intertrochanteric crest
– lateral rotation
– innervated by nerve to quadratus femoris
BLOOD SUPPLY
Mostly via the superior and inferior gluteal arteris (branches of the internal iliac artery). Venous drainage follows the arterial supply.
VARIANTS
Question 15 – Lymph nodes of the lower limb
Write short notes on the anatomy of the Lymph nodes of the lower limb.
OVERVIEW
Drains tissue fluid, plasma protein and cellular debris into the blood stream.
VESSELS
Medial vessels
– follow the course of the great saphenous vein
– originate on the dorsal surface of the foot and ascend with the great saphenous vein, passing behind the medialy condyle
– drains into the subinguinal group of the inguinal lymph nodes in the groin
Lateral vessels
– follow the small saphenous vein
– arise from the lateral surface of the foot and ascends with the small saphenous vein to enter the popliteal nodes or otherwise joins the medial group
Deep lymphatic vessels
Fewer than superficial counterparts and accompany the deep arteries of the lower leg.
Three main groups: anterior tibial, posterior tibial and peroneal following the corresponding artery and enters the popliteal lymph nodes.
NODES
Superficial Inguinal Nodes
– below the inguinal ligament and drain the penis, scrotum, perineum, buttock and abdominal wall
Superficial Sub-Inguinal Nodes
– located on each side of the proximal section of the great saphenous vein and receive superficial lymphatic vessels of the lower leg
Deep Sub-Inguinal Nodes
– medial aspect of the femoral vein
– receive deep lymphatic vessels of the thigh
Popliteal Nodes
– found embedded in popliteal fossa fat
– receive lymph from the lateral superficial vessels
– pass alongside the femoral vessels to empty into the deep inguinal nodes or alongside the great saphenous vein to drain into the subinguinal nodes