Comprehensive Upper & Lower Limb Anatomy – Muscles, Nerves, Joints & Vasculature

What are the three muscular teams for dynamic shoulder stabilisation?

The three overlapping muscular 'teams' for dynamic stabilisation of the shoulder complex are Rotator-cuff, Scapular stabilisers, and Power muscles.

Name the Scapular Stabilisers.

Trapezius, Levator scapulae, Rhomboid major & minor, Serratus anterior, and Pectoralis minor.

What are the two main accessory joint movements (arthrokinematics)?

Glide/slide and Roll.

What are the boundaries of the Quadrangular Space (TIQS mnemonic)?

Superior – Teres minor, Inferior – Teres major, Medial – Long head of triceps brachii, Lateral – Surgical neck of humerus.

What are the contents of the Quadrangular Space?

Axillary n. and Posterior circumflex humeral a. & v.

Name the prime elbow flexors.

Brachialis (work-horse), Biceps brachii, and Brachioradialis.

What are the borders and floor of the Anatomical Snuff-box?

Lateral border: Abductor pollicis longus & Extensor pollicis brevis; Medial border: Extensor pollicis longus; Floor: Scaphoid bone.

Describe the classical nerve lesions of the Upper Limb.

Median n. palsy ('Ape hand', 'Benediction/Bishop’s sign'), Radial n. palsy ('Wrist drop'), Ulnar n. palsy ('Claw hand', 'Cyclist’s palsy').

What are the key myotome test and dermatome for nerve root L1?

Motor: psoas; Sensory: Iliac crest → groin.

What is the key myotome test for nerve root L2?

Hip flexion.

What is the key myotome test for nerve root L3?

Knee extension (quadriceps).

What is the key myotome test for nerve root L4?

Ankle dorsiflexion (tibialis ant.).

What is the key myotome test for nerve root L5?

Great-toe extension (EHL).

What is the key myotome test for nerve root S1?

Plantar-flexion / subtalar eversion.

What is the key myotome test for nerve root S2?

Knee flexion (hamstrings).

Which reflex is associated with nerve roots L2 and L3?

Patellar.

Which reflex is associated with nerve root S1?

Achilles.

Where does the aorta bifurcate in the lower extremity arterial tree?

The aorta bifurcates into R/L common iliac aa. at L4.

What artery becomes the femoral artery at the inguinal ligament?

External iliac artery.

What are the two main branches of the popliteal artery?

Anterior tibial a. (→ dorsalis pedis a.) and Posterior tibial a. (→ fibular (peroneal) a. + plantar branches).

Name the two main superficial veins of the lower limb and their termination points.

Small saphenous v. (posterior leg) → popliteal v.; Great saphenous v. (medial leg/thigh) → femoral v.

List the dynamic stabilisers of the shoulder.

Rotator cuff “SITS” (Supraspinatus, Infraspinatus, Teres minor, Subscapularis), Scapular stabilisers, and Power muscles.

List the static stabilisers of the shoulder.

Bony geometry, Glenoid labrum, Joint capsule, and Glenohumeral ligs. ('LAC, CCCC').

What are the boundaries of the Femoral Triangle?

Superior – inguinal ligament; Lateral – sartorius; Medial – adductor longus.

What are the contents of the Femoral Triangle from lateral to medial?

Femoral Nerve, Femoral Artery, Femoral Vein, Empty space (femoral canal), Lymph nodes (Cloquet’s). ('NAVEL' mnemonic).

What are the boundaries of the Quadrangular Space?

The boundaries of the quadrangular space are Teres minor (superior), Teres major (inferior), Long head of triceps brachii (medial), and Surgical neck of humerus (lateral).

What are the contents of the Quadrangular Space?

The contents of the Quadrangular Space are the Axillary n. and the Posterior circumflex humeral a. & v.

Name the prime movers for elbow flexion.

The prime elbow flexors are brachialis, biceps brachii, and brachioradialis.

What is a classical sign of Median nerve palsy?

The characteristic sign of median n. palsy is "Ape hand" (loss of thumb opposition) or "Benediction/Bishop’s sign" on attempted fist.

What is a classical sign of Radial nerve palsy?

The characteristic sign of radial n. palsy is "Wrist drop" (loss of wrist/finger extensors).

What is a classical sign of Ulnar nerve palsy?

The characteristic sign of ulnar n. palsy is "Claw hand" or "Cyclist’s palsy" (handle-bar compression in Guyon’s canal).

What structures are innervated by the Sciatic Nerve Complex and what are its main divisions?

The Sciatic n. (largest) supplies the hamstrings + HS part of adductor magnus. It divides into the Tibial division (posterior superficial & deep compartments of leg → sural n.) and the Common peroneal (fibular) division (Deep branch → anterior compartment; Superficial branch → lateral compartment).

At what vertebral level does the aorta bifurcate?

The aorta bifurcates into the R/L common iliac aa. at the L4 vertebral level.

Where does the femoral artery transition into the popliteal artery?

The femoral artery becomes the popliteal artery after passing through the adductor canal.

Name the muscles of the rotator cuff (SITS mnemonic).

The "SITS" muscles of the rotator cuff are Supraspinatus, Infraspinatus, Teres minor, and Subscapularis.

Q: What are the three overlapping muscular teams responsible for dynamic stabilization of the shoulder complex?

A: Dynamic stabilization of the shoulder complex relies on: Rotator-cuff (fine-tuning, compression), Scapular stabilisers (position the glenoid), and Power muscles (generate large torques).

Q: Which muscles are considered scapular stabilisers, responsible for positioning the glenoid?

A: The scapular stabilisers are: Trapezius, Levator scapulae, Rhomboid major & minor, Serratus anterior, and Pectoralis minor.

Q: Name the power muscles that generate large torques acting on the shoulder girdle.

A: The power muscles acting on the shoulder girdle are: Deltoid, Pectoralis major, Latissimus dorsi, and Teres major.

Q: In arthrokinematics, what defines a 'glide' or 'slide' movement?

A: A 'glide' or 'slide' occurs when one single point of one joint surface meets a series of new points on the opposing surface.

Q: What is a 'roll' movement in arthrokinematics?

A: A 'roll' is when a series of new points on each surface meet one another, similar to a tyre rolling along the road.

Q: How do combined roll and glide movements contribute to preventing shoulder impingement during overhead elevation?

A: Combined roll + glide keeps the humeral head centred on the glenoid during overhead elevation, which prevents impingement.

Q: What are the boundaries and contents of the quadrangular space?

A: Boundaries of the quadrangular space are: Superior – Teres minor, Inferior – Teres major, Medial – Long head of triceps brachii, Lateral – Surgical neck of humerus. Its contents include: Axillary n., and Posterior circumflex humeral a. & v.

Q: What is the clinical significance of nerve entrapment in the quadrangular space?

A: Entrapment in the quadrangular space accounts for \approx 11\% of non-traumatic axillary neuropathies, presenting with pain and deltoid weakness.

Q: Describe the bony partners and motions of the ulno-humeral articulation.

A: The ulno-humeral articulation involves the trochlea of the humerus and the trochlear notch of the ulna, primarily allowing flexion/extension movements in the sagittal plane.

Q: What are the bony partners of the radio-humeral articulation and its primary function?

A: The radio-humeral articulation is formed by the capitulum of the humerus and the head of the radius. It primarily provides a buttress during valgus load with little pure motion.

Q: Describe the proximal radio-ulnar articulation and its primary movements.

A: The proximal radio-ulnar articulation involves the head of the radius and the radial notch of the ulna. It is a pivot joint that allows pronation / supination.

Q: Which muscles are the prime movers for elbow flexion?

A: The prime elbow flexors are the brachialis, biceps brachii, and brachioradialis.

Q: Which muscles are responsible for elbow extension?

A: The elbow extensors are the triceps brachii and anconeus.

Q: Name the primary wrist extensors and a muscle that assists forearm rotation.

A: The primary wrist extensors are extensor carpi radialis longus & brevis, extensor carpi ulnaris, and extensor digitorum. The supinator muscle assists forearm rotation.

Q: Which muscles are the prime movers for wrist flexion, and which muscle also pronates and weakly flexes?

A: The prime wrist flexors are flexor carpi radialis, flexor carpi ulnaris, palmaris longus, and flexor digitorum superficialis. The pronator teres also pronates and weakly flexes the wrist.

Q: What are the borders and floor of the anatomical snuff-box?

A: The borders of the anatomical snuff-box (lateral ➜ medial) are Abductor pollicis longus & Extensor pollicis brevis, and Extensor pollicis longus. The floor is the scaphoid bone (\approx 70\% of carpal fractures).

Q: What are the characteristic signs of Median Nerve Palsy?

A: Median Nerve Palsy is characterized by loss of thumb opposition ("Ape hand") and a "Benediction/Bishop’s sign" on attempted fist.

Q: What is a classic sign of Radial Nerve Palsy?

A: A classic sign of Radial Nerve Palsy is "Wrist drop", due to the loss of wrist/finger extensors.

Q: What are the common manifestations of Ulnar Nerve Palsy?

A: Ulnar Nerve Palsy typically presents as "Claw hand" and can be associated with "Cyclist’s palsy" (due to handle-bar compression in Guyon’s canal).

Q: Describe the motor and sensory innervation of the Iliohypogastric Nerve (L1).

A: The Iliohypogastric Nerve (L1) provides motor innervation to the internal oblique and transversus abdominis, and sensory innervation to the posterolateral gluteal skin.

Q: What are the motor and sensory functions of the Ilioinguinal Nerve (L1)?

A: The Ilioinguinal Nerve (L1) has similar motor functions as the Iliohypogastric nerve (internal oblique, transversus abdominis), and provides sensory innervation to the upper medial thigh and genital region.

Q: Outline the motor and sensory innervation of the Genitofemoral Nerve (L1,2).

A: The Genitofemoral Nerve (L1,2) provides motor innervation to the cremaster muscle and sensory innervation to the scrotum / mons pubis.

Q: What is the innervation pattern of the Lateral Femoral Cutaneous Nerve (L2,3) and what condition is associated with its entrapment?

A: The Lateral Femoral Cutaneous Nerve (L2,3) is purely sensory, innervating the anterolateral thigh to the knee. Its entrapment under the inguinal ligament can cause meralgia paraesthetica.

Q: Describe the motor and sensory innervation of the Femoral Nerve (L2-4).

A: The Femoral Nerve (L2-4) provides motor innervation to the iliacus, pectineus, sartorius, and quadriceps muscles. Its sensory distribution covers the anterior thigh and medial leg (via the saphenous nerve).

Q: Which muscles does the Obturator Nerve (L2-4) innervate, what is its sensory distribution, and what mnemonic is used for its motor branches?

A: The Obturator Nerve (L2-4) innervates the obturator externus, adductor magnus/longus/brevis, pectineus, and gracilis muscles. It provides sensory innervation to the medial thigh. The mnemonic for its motor branches is “AAAGOP” (Adductors ×3, Gracilis, Obturator externus, Pectineus).

Q: Which muscles are innervated by the Superior Gluteal Nerve, and what clinical sign is associated with its weakness?

A: The Superior Gluteal Nerve innervates the gluteus medius/minimus and tensor fascia latae muscles. Weakness in these muscles can lead to a positive Trendelenburg sign.

Q: What muscle is innervated by the Inferior Gluteal Nerve, and what activities are affected by its weakness?

A: The Inferior Gluteal Nerve innervates the gluteus maximus. Weakness of this muscle primarily affects activities like climbing stairs and rising from a seated position.

Q: What area does the Perforating Cutaneous Nerve innervate?

A: The Perforating Cutaneous Nerve supplies sensory innervation to the skin of the inferior-medial buttock.

Q: What is the function of the Nerve to Piriformis?

A: The Nerve to Piriformis directly innervates the piriformis muscle.

Q: What structures do the Pelvic Splanchnic Nerves (S2-S4 parasympathetic) innervate?

A: The Pelvic Splanchnic Nerves (S2-S4 parasympathetic) innervate the bladder and distal colon.

Q: What is Meralgia Paraesthetica and what is its common cause?

A: Meralgia Paraesthetica is a condition characterized by burning lateral thigh pain, commonly caused by the entrapment of the lateral femoral cutaneous nerve under the inguinal ligament, often by tight belts.

Q: What are the main branches of the Profunda Femoris artery?

A: The main branches of the Profunda Femoris artery are the medial and lateral femoral circumflex arteries.

Q: Describe the main characteristics and divisions of the Sciatic Nerve Complex.

A: The Sciatic Nerve is the largest nerve, supplying the hamstrings and the hamstring part of the adductor magnus, and it divides into the tibial and common peroneal (fibular) divisions.

Q: What areas and nerves are supplied by the Tibial Division of the Sciatic Nerve?

A: The Tibial Division of the Sciatic Nerve supplies the posterior superficial & deep compartments of the leg and gives rise to the sural nerve.

Q: What are the two main branches of the Common Peroneal (Fibular) Division of the Sciatic Nerve and what compartments do they supply?

A: The Common Peroneal (Fibular) Division of the Sciatic Nerve branches into the Deep branch (supplying the anterior compartment) and the Superficial branch (supplying the lateral compartment).

Q: What are the main groups of dynamic shoulder stabilisers?

A: The main dynamic shoulder stabilisers are the Rotator cuff “SITS” (Supraspinatus, Infraspinatus, Teres minor, Subscapularis), Scapular stabilisers, and Power muscles.

Q: What are the key static stabilizers of the shoulder joint?

A: The key static shoulder stabilisers include: Bony geometry (humeral head on glenoid fossa, \approx \frac13 coverage), Glenoid labrum (fibrocartilaginous rim deepening socket by \approx 50\%), Joint capsule (redundant inferiorly; taut superiorly), and Glenohumeral ligaments (superior, middle, inferior complexes, often remembered as “LAC, CCCC”).

Q: What are the boundaries of the femoral triangle?

A: The boundaries of the femoral triangle are: Superior – inguinal ligament, Lateral – sartorius, and Medial – adductor longus.

Q: What forms the floor of the femoral triangle?

A: The floor of the femoral triangle is formed by the iliopsoas (laterally) and the pectineus (medially).

Q: Using the 'NAVEL' mnemonic, list the contents of the femoral triangle from lateral to medial.

A: The contents of the femoral triangle (lateral → medial) are “NAVEL”: Femoral Nerve, Femoral Artery, Femoral Vein, Empty space (femoral canal), and Lymph nodes (Cloquet’s).

Q: What are the clinical significances of the femoral triangle?

A: The femoral triangle is a common site for arterial catheterisation, and femoral hernias can protrude through its femoral canal (medial to the vein).

Q: What symptoms are associated with piriformis hypertrophy and sciatic nerve compression?

A: Piriformis hypertrophy can cause sciatic nerve compression, leading to pain radiating in the L4→S3 dermatome distribution.

Q: How is shoulder impingement typically managed in terms of joint mechanics?

A: Shoulder impingement is often managed by enhancing the inferior glide of the humeral head.

Q: How should a fall on an out-stretched hand (FOOSH) with anatomical snuff-box tenderness be managed, even if X-rays are negative?

A: A fall on an out-stretched hand (FOOSH) causing tenderness in the anatomical snuff-box should be treated as a scaphoid fracture, even if initial X-rays are negative, due to the bone's retrograde blood supply and risk of avascular necrosis.

Q: How can a popliteal aneurysm be differentiated from a Baker's cyst clinically?

A: A popliteal aneurysm may mimic a Baker’s cyst, but differentiation requires palpation of distal pulses (dorsalis pedis, posterior tibial), which would be affected by an aneurysm.

Q: For what surgical procedure is the Great Saphenous Vein commonly harvested, and what anatomical landmark protects a nearby nerve during incision?

A: The Great Saphenous Vein is commonly harvested for Coronary Artery Bypass Grafting (CABG). During incision, placing it just anterior to the medial malleolus helps protect the saphenous nerve.