Human Anatomy Part 1 - K. A. Dyubenko, A. K. Kolomiysev, Yu. B. Chaykovsky 2002

Special Part
Myology, myologia [the study of muscles] - Muscles and fasciae of the upper limb
Muscles of the upper limb, musculi membri superioris - Muscles of the free upper limb - Muscles of the hand - Muscles of the thenar eminence

1. Abductor pollicis brevis Muscle, m. abductor pollicis brevis — located superficially, originates from the flexor retinaculum, the tubercle of the scaphoid bone, and the forearm fascia; inserts on the radial side of the proximal phalanx of the thumb.

Class="center">

Fig. 162. Muscles of the hand, palmar surface; thenar muscles, hypothenar muscles, and middle group (after V. P. Vorobyov)

Fig. 163. Muscles of the hand, palmar surface; thenar eminence and interosseous muscles (after V. P. Vorobyov)

Function: abducts the thumb.

Blood supply: superficial palmar branch of the radial artery (r. palmaris superficialis, a. radialis).

Innervation: median nerve (n. medianus, C VI–C VII).

2. Flexor pollicis brevis muscle, m. flexor pollicis brevis — has two heads: the superficial HEAD originates from the flexor retinaculum, while the deep head originates at the floor of the carpal canal from the trapezium, trapezoid, and capitate bones; inserts on the lateral sesamoid bone and the proximal phalanx of the thumb.

Function: flexes the thumb at the metacarpophalangeal joint.

Blood supply: superficial palmar branch, radial artery, deep palmar arch (r. palmaris superficialis, a. radialis, arcus palmaris profundus).

Innervation: superficial head — median nerve (n. medianus, C VI–C VII); deep head — ulnar nerve (n. ulnaris, C VI–Th I).

3. Opponens pollicis muscle, m. opponens pollicis — originates from the tubercle of the trapezium and the flexor retinaculum, inserts on the radial border of the first metacarpal bone.

Function: opposes the thumb to the other digits.

Blood supply: superficial palmar branch, radial artery, deep palmar arch (r. palmaris superficialis, a. radialis, arcus palmaris profundus).

Innervation: median nerve (n. medianus, C VI–C VII).

4. Adductor pollicis muscle, m. adductor pollicis — triangular in shape, located deep within the palm. The muscle has two heads: oblique and transverse. The oblique head, caput obliquum, originates from the radiate carpal ligament, capitate bone, and the palmar surfaces of the second and third Metacarpal bones (II and III); the transverse head, caput transversum, originates from the palmar surface of the third metacarpal bone (III) and the heads of the second through fourth metacarpal bones (II–IV). The muscle fibers of both heads converge and insert onto the Base of the proximal phalanx of the thumb and the ulnar sesamoid bone.

Function: adducts the thumb and partially participates in its opposition and flexion of the proximal phalanx.

Blood supply: superficial and deep palmar arches (arcus palmares superficialis et profundus).

Innervation: ulnar nerve (n. ulnaris, C VIII).