MRI of the hand

Table 8-1.

Muscles of the Hand

MUSCLE	ORIGIN	INSERTION	NERVE SUPPLY
Palmaris brevis	Ulnar border of the palmar aponeurosis	Deep surface of the skin along the ulnar border of the palm	Superficial branch of ulnar (C8, T1)
Abductor pollicis brevis	Palmar surface of the flexor retinaculum, trapezium, and, occasionally, scaphoid	Radial side of the base of the proximal phalanx of the thumb	Recurrent branch of median (C8, T1)
Opponens pollicis	Palmar surface of the flexor retinaculum and tubercle of the trapezium	Lateral part of the palmar surface of the shaft of the first metacarpal	Recurrent branch of median (C8, T1)
Flexor pollicis brevis	Superficial head: trapezium, adjacent part of the flexor retinaculum, and tendon sheath of the flexor carpi radialis; deep head: trapezoid and capitate	Superficial head: lateral side of the palmar aspect of the base of the proximal phalanx; deep head: into a tendon of the superficial head	Recurrent branch of median and deep branch of ulnar (C8, T1)
Adductor pollicis brevis	Carpal head: flexor retinaculum, capitate, bases of the second and third metacarpals; metacarpal head: palmar ridges of the third metacarpal and capsules of the second, third, and fourth metacarpophalangeal articulations	Ulnar side of the palmar aspect of the base of the proximal phalanx of the thumb	Recurrent branch of median (C8, T1)
Abductor digiti minimi	Distal half of the pisiform, pisihamate ligament, tendon of the flexor carpi ulnaris, and, frequently, the flexor retinaculum	Two tendons: (1) the ulnar side of the base of the proximal phalanx of the little finger, and (2) the aponeurosis of the extensor tendon of the little finger	Deep palmar division of ulnar (C8, T1)
Flexor digiti minimi brevis	Hook of the hamate and adjacent parts of the flexor retinaculum	Ulnar side of the base of the proximal phalanx of the little finger	Superficial or deep palmar branch of ulnar (C8, T1)
Opponens digiti minimi	Distal border of the hook of the hamate and adjacent flexor retinaculum	Medial surface of the body and particularly onto the head of the fifth metacarpal	Deep palmar branch of ulnar (C8, T1)
Lumbrical	Two lateral lumbricals: radial and palmar sides of the first and second tendons of the flexor digitorum profundus; two medial lumbricals: adjacent side of the second and third tendons, and the third and fourth tendons of the flexor digitorum profundus	Into the radial border of the tendon of the extensor digitorum on the dorsal aspect of the proximal phalanx	Median, lateral two or three lumbricals; ulnar, deep palmar branch, medial one or two lumbricals (C8, T1)
Interosseous	Palmar interosseous: anterior border of the shaft of the first, second, fourth, and fifth metacarpals. The first arises near the base and the others arise from three fourths of the shaft of the bone. Dorsal interosseous: adjacent sides of the metacarpal bones in each metacarpal interspace	Into the expansion on the axial side of the corresponding digit. The first palmar interosseous is described frequently as a division of the flexor brevis or adductor pollicis. The first dorsal interosseous usually inserts onto the proximal phalanx. The other three insert into the extensor expansion and proximal phalanx	Deep palmar branch of ulnar (C8, T1)