Lesson 14: Anatomy of the Anterior Forearm and Hand

Vocabulary flashcards covering the osteology, joints, musculature layers, actions, and nerve innervations of the anterior forearm and hand from Lesson 14.

Common flexor origin (CFO)

The medial epicondyle of the humerus, where 5 flexion muscles attach.

Interosseus membrane

A syndesmosis joint that binds the radius and ulna together and forms a boundary between the posterior and anterior sides.

Proximal row of carpal bones

The row of carpal bones consisting of the pisiform (which sticks out anteriorly), triquetrum, lunate, and scaphoid.

Distal row of carpal bones

The row of carpal bones consisting of the hamate, capitate, trapezoid, and trapezium.

Metacarpophalangeal joints

Condyloid joints located between the metacarpals and phalanges.

Proximal and distal interphalangeal joints

Hinge joints located between the phalanges.

Radiocarpal joint

A condyloid wrist joint that connects the radius and the carpal bones.

Flexor retinaculum

A band of connective tissue connecting the hamate, pisiform, trapezium, and scaphoid that retains long flexor tendons from popping out anteriorly and helps form the carpal tunnel.

Pronator teres

A superficial anterior forearm muscle with a humeral head (CFO) and an ulnar head (coronoid process) attaching to the lateral surface of the radius; innervated by the median nerve to perform pronation and flexion of the forearm.

Flexor carpi radialis

A superficial anterior forearm muscle originating at the CFO and inserting into the base of the 2nd metacarpal; innervated by the median nerve to perform flexion of the hand/forearm and abduction of the hand.

Palmaris longus

A superficial anterior forearm muscle originating at the CFO and inserting into the palmar aponeurosis; innervated by the median nerve to flex the forearm and hand.

Palmar aponeurosis

A sheet-like tendon in the hand that protects underlying structures and is involved in tensing (such as during gripping or rock climbing).

Flexor carpi ulnaris

A superficial anterior forearm muscle running from the CFO to the pisiform, hamate, and 5th metacarpal; innervated by the ulnar nerve to produce flexion of the forearm/hand and adduction.

Flexor digitorum superficialis

An intermediate layer anterior forearm muscle originating from the CFO, anterior border of the radius, and coronoid process to the shafts of the middle phalanges (splitting to accommodate other tendons); innervated by the median nerve to flex the forearm, hand, metacarpophalangeal, and proximal interphalangeal joints.

Deep layer of anterior forearm

A muscle layer whose origin is not the CFO and whose members are all innervated by the anterior interosseous nerve (derived from the median nerve).

Flexor digitorum profundus

A deep anterior forearm muscle extending from the interosseous membrane to the distal phalanges; innervated by both the ulnar nerve and anterior interosseous nerve to flex the hand, metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints.

Flexor pollicis longus

A deep anterior forearm muscle extending from the anterior surface of the radius and interosseous membrane to the base of the distal phalanx of the thumb; innervated by the anterior interosseous nerve to flex the hand MCP and IP joint of digit 1.

Pronator quadratus

A deep transverse forearm muscle that extends from the ulna to the radius to bind them and causes pronation of the forearm; innervated by the anterior interosseous nerve.

Flexor-pronator compartment of the forearm

The muscle compartment of the forearm that causes flexion at joints proximal to its insertion.

Median nerve

A major nerve that travels between the humeral and ulnar heads of the pronator teres, and between flexor digitorum superficialis and profundus; innervates pronator teres, flexor carpi radialis, palmaris longus, and flexor digitorum superficialis.

Anterior interosseous nerve

A nerve branch arising from the median nerve that innervates the deep layer muscles: flexor digitorum profundus, flexor pollicis longus, and pronator quadratus.

Ulnar nerve

A nerve traveling medial and posterior to the CFO and outside the carpal tunnel; innervates flexor carpi ulnaris and flexor digitorum profundus.