hand muscles Origins, Insertions, Actions Flashcards
abductor pollicis brevis
O: Flexor retinaculum, scaphoid & trapezium
I: Radial side of proximal phalanx (of thumb)
A: abduct thumb; assist flexion at MCP joint
Flexor pollicis brevis
O: Flexor retinaculum, trapezium, and capitate
I: Base of palmar surface of proximal phalanx (of thumb)
A: flexes MCP&CMC joint; assist opposition and adduction of thumb
opponens pollicis
O: Flexor retinaculum and trapezium
I: The whole length of the radial side of the palmer surface of 1st metacarpal
A: Opposition of the thumb
adductor pollicis
O: Transverse head - palmar surface of the body of 3rd metacarpal; oblique head - palmar surface of the bases of 2nd and 3rd metacarpals, and capitate (sometimes trapezoid and trapezium)
I: Ulnar side of palmar surface of base of proximal phalanx of thumb
A: Adducts thumb (1st metacarpal); assists flexion at CMC joint. assists in opposition; weak flexor at MCP
abductor digiti minimi
O: Pisiform bone; (also often the tendon of flexor carpi ulnaris)
I: Ulnar surface of base of proximal phalanx of little finger, extensor hood
A: Abduct little finger at MCP joint, assist flexion at MCP; weak IP extensor
flexor digiti minimi brevis
O: Hook of hamate and flexor retinaculum
I: Ulnarly and slightly palmarly on the proximal phalanx of little finger
A: Flex little finger (proximal phalanx at MCP)
opponens digiti minimi
O: Hook of hamate and flexor retinaculum
I: Ulnar border of shaft of 5th metacarpal
A: Draws the little finger anteriorly (out of the palm) and rotates it radially, brining it into opposition with thumb and deepening the hollow of the hand
Lumbricals
O: 1st and 2nd - Radial sides of flexor digitorum tendons to index and middle finger, respectively; 3rd and 4th - Adjacent sides of FDP tendons to middle and ring, and ring and little fingers, respectively
I: Radial sides of extensor aponeurosis (dorsal hood) of fingers 2-5
A: Flex at MCP joints, extend at IP joints (“she’s this tall” gesture)
Dorsal interossei
O: Adjacent surfaces of metacarpals
I: 1st & 2nd - radial sides of bases of proximal phalanx of 2nd/3rd digit, and dorsal hood
3rd & 4th - ulnar sides of bases of proximal phalanx of 3rd and 4th digit, and dorsal hood
A: Abduct 2nd, 3rd, and 4th digits; assist MCP flexion & IP extension
Dorsal interossei
O: Adjacent surfaces of metacarpals
I: 1st & 2nd - radial sides of bases of proximal phalanx of 2nd/3rd digit, and dorsal hood
3rd & 4th - ulnar sides of bases of proximal phalanx of 3rd and 4th digit, and dorsal hood
A: Abduct 2nd, 3rd, and 4th digits; assist MCP flexion & IP extension
Palmar interossei
O: Adjacent surfaces of metacarpals
I:
