Upper Limb Anatomy, Innervation, and Clinical Correlations

Vocabulary practice flashcards covering upper limb anatomy, muscular and cutaneous innervations, brachial plexus pathology, and clinical syndromes.

Glenoid cavity

A shallow shoulder socket that articulates with the head of the humerus, allowing rotational mobility.

Glenoid labrum

A fibrocartilaginous structure that helps increase the depth of the shallow glenoid cavity.

Median cubital vein

A superficial vein connecting the cephalic and basilic veins within the cubital fossa, frequently utilized for venipuncture.

Plane joint

A nonaxial synovial joint with flat articular surfaces allowing short gliding movements without rotation around an axis, such as intercarpal joints.

Condylar (ellipsoid) joint

A biaxial joint permitting movement along two axes (side-to-side abduction-adduction and back-and-forth flexion-extension), exemplified by metacarpophalangeal joints.

Dorsal interossei muscles

Four bipennate hand muscles innervated by the ulnar nerve that cause flexion at MCP joints, extension at IP joints, and abduction of the second to fourth digits.

Palmar interossei muscles

Three hand muscles innervated by the ulnar nerve that flex the MCP joints and extend and adduct the second, fourth, and fifth digits toward the third digit.

Winged scapula

A clinical condition where the scapula protrudes posteriorly due to loss of innervation to the serratus anterior (long thoracic nerve) or rhomboids (dorsal scapular nerve); intact arm elevation above $90^{\circ}$ indicates rhomboid involvement.

Radial and axillary nerves innervation

The muscular and cutaneous distribution patterns of the posterior cord branches, supplying extensor compartments of the arm/forearm and the deltoid/teres minor region.

Musculocutaneous, median, and ulnar nerves innervation

The muscular and cutaneous innervation distribution patterns of the anterior division terminal branches of the brachial plexus across the flexor compartments of the arm, forearm, and hand.

Erb-Duchenne paralysis

An upper brachial plexus ($C5\text{--}C6$) avulsion injury characterized by paralysis of the deltoid, supraspinatus, infraspinatus, biceps, and brachialis, leading to arm adduction, medial rotation, loss of elbow flexion, and weakened supination.

Klumpke's paralysis

A lower brachial plexus ($C8\text{--}T1$) injury causing atrophic paralysis of forearm and intrinsic hand muscles, presenting clinically as a claw hand deformity.

Colles' fracture

A fracture of the radial styloid process with posterior displacement forced into the shaft, typically resulting from a fall onto an extended hand.

Pronator quadratus

A deep anterior forearm muscle originating on the distal quarter of the ulna and inserting on the distal quarter of the radius, innervated by the median nerve to pronate the hand and stabilize the distal radioulnar joint.

Brachioradialis

A posterior compartment forearm muscle originating from the distal humerus and inserting at the radial styloid process; acts functionally as an elbow flexor and semipronator, innervated by the radial nerve.

Carpal tunnel

An osteofibrous canal formed by the anterior carpal groove and the flexor retinaculum, transmitting the median nerve, flexor pollicis longus tendon, and the tendons of flexor digitorum superficialis and profundus.

Scaphoid bone fracture

The most common carpal fracture, typically occurring at the narrowed waist; susceptible to avascular necrosis and nonunion because its blood supply enters via the distal pole.

Lunate

The most frequently dislocated carpal bone of the wrist.

Gouty arthritis

A metabolic disease ("king's disease") in which excess uric acid in the blood precipitates into salt crystals within joints, eroding cartilage and causing pain, reduced mobility, and potential bone fusion.

Wrist drop

A clinical motor deficit characterized by inability to extend the wrist and fingers, caused by injury to the radial nerve (e.g., humeral mid-shaft fractures or deep radial nerve injury).

Hand of benediction

A clinical presentation of high median nerve injury (above the elbow) where attempting to make a fist leaves digits I, II, and III extended due to paralysis of flexors and lateral lumbricals.