Muscles of the Forearm and Hand

Vocabulary flashcards covering the origin, insertion, action, and innervation of forearm and hand muscles based on lecture material.

Anterior Forearm Compartment

Forearm compartment containing 8 muscles that function as pronators of the forearm and flexors of the wrist and digits; all are innervated by the median nerve except 1 1/2 muscles (Flexor carpi ulnaris and medial half of Flexor digitorum profundus) innervated by the ulnar nerve.

Posterior Forearm Compartment

Forearm compartment containing supinators of the forearm and extensors of the wrist and digits; all muscles in this compartment are innervated by the radial nerve with no exceptions.

Superficial Anterior Forearm Muscles

Group of 5 muscles (Pronator teres, Flexor carpi radialis, Palmaris longus, Flexor carpi ulnaris, and Flexor digitorum superficialis) that all originate on or near the medial epicondyle of the humerus.

Pronator teres m.

Superficial anterior forearm muscle that pronates the forearm and flexes the elbow; innervated by the median nerve.

Flexor carpi radialis m.

Superficial anterior forearm muscle that flexes and abducts the wrist; innervated by the median nerve.

Palmaris longus m.

Superficial anterior forearm muscle that flexes the wrist; innervated by the median nerve.

Flexor carpi ulnaris m.

Superficial anterior forearm muscle that flexes and adducts the wrist; innervated by the ulnar nerve.

Flexor digitorum superficialis m.

Superficial anterior forearm muscle that flexes digits 2-5 and flexes the wrist; innervated by the median nerve.

Deep Anterior Forearm Muscles

Group of 3 muscles (Flexor digitorum profundus, Flexor pollicis longus, and Pronator quadratus) that all originate on the interosseous membrane or radius/ulna.

Flexor digitorum profundus m.

Deep anterior forearm muscle that flexes digits 2-5 and flexes the wrist; innervated by the median nerve for digits 2 & 3, and by the ulnar nerve for digits 4 & 5.

Flexor pollicis longus m.

Deep anterior forearm muscle that flexes the pollex and flexes the wrist; innervated by the median nerve.

Pronator quadratus m.

Deep anterior forearm muscle that pronates the forearm; innervated by the median nerve.

Superficial Posterior Forearm Muscles

Group of 7 muscles (Brachioradialis, Extensor carpi radialis longus, Extensor carpi radialis brevis, Extensor digitorum, Extensor digiti minimi, Extensor carpi ulnaris, and Anconeus) that all originate on or near the lateral epicondyle of the humerus.

Brachioradialis m.

Superficial posterior forearm muscle that flexes the elbow (despite being in the posterior compartment); innervated by the radial nerve.

Extensor carpi radialis longus m.

Superficial posterior forearm muscle that extends and abducts the wrist; innervated by the radial nerve.

Extensor carpi radialis brevis m.

Superficial posterior forearm muscle that extends and abducts the wrist; innervated by the radial nerve.

Extensor digitorum m.

Superficial posterior forearm muscle that extends digits 2-5 and extends the wrist; innervated by the radial nerve.

Extensor digiti minimi m.

Superficial posterior forearm muscle that extends digit 5 and extends the wrist; innervated by the radial nerve.

Extensor carpi ulnaris m.

Superficial posterior forearm muscle that extends and adducts the wrist; innervated by the radial nerve.

Anconeus m.

Superficial posterior forearm muscle that extends the elbow; innervated by the radial nerve.

Deep Posterior Forearm Muscles

Group of 5 muscles (Supinator, Abductor pollicis longus, Extensor pollicis brevis, Extensor pollicis longus, and Extensor indicis) that all originate on the interosseous membrane or radius/ulna.

Supinator m.

Deep posterior forearm muscle that supinates the forearm; innervated by the radial nerve.

Abductor pollicis longus m.

Deep posterior forearm muscle that abducts and extends the pollex; innervated by the radial nerve.

Extensor pollicis brevis m.

Deep posterior forearm muscle that extends the pollex; innervated by the radial nerve.

Extensor pollicis longus m.

Deep posterior forearm muscle that extends the pollex; innervated by the radial nerve.

Extensor indicis m.

Deep posterior forearm muscle that extends digit 2 (index finger); innervated by the radial nerve.

Intrinsic Hand Muscles

Collection of 20 total intrinsic hand muscles; 5 are innervated by the median nerve, and the remaining 15 are innervated by the ulnar nerve.

Abductor digiti minimi m.

Hypothenar eminence muscle that abducts digit 5; innervated by the ulnar nerve.

Flexor digiti minimi brevis m.

Hypothenar eminence muscle that flexes digit 5; innervated by the ulnar nerve.

Opponens digiti minimi m.

Hypothenar eminence muscle that opposes digit 5 (abducts, flexes, & rotates digit 5); innervated by the ulnar nerve.

Abductor pollicis brevis m.

Thenar eminence muscle that abducts the pollex; innervated by the median nerve.

Flexor pollicis brevis m.

Thenar eminence muscle that flexes the pollex; innervated by the median nerve.

Opponens pollicis m.

Thenar eminence muscle that opposes the pollex (abducts, flexes, & rotates digit 1); innervated by the median nerve.

Lumbrical muscles

Four intrinsic hand muscles numbered 1-4 from lateral to medial; lumbricals 1 & 2 are innervated by the median nerve, and lumbricals 3 & 4 are innervated by the ulnar nerve; they flex at the MP joint & extend at the IP joint.

Adductor pollicis m.

Intrinsic hand muscle that adducts the pollex; innervated by the ulnar nerve.

Palmar interosseous mm.

Intrinsic hand muscles responsible for adduction of the digits (PAD); innervated by the ulnar nerve.

Dorsal interosseous mm.

Intrinsic hand muscles responsible for abduction of the digits (DAB); innervated by the ulnar nerve.

Palmaris brevis m.

Intrinsic hand muscle that wrinkles the skin and may protect the ulnar nerve and artery; innervated by the ulnar nerve.