Anatomy LB3

abductor pollicis brevis

origin: flexor retinaculum, scaphoid and trapezium

insertion: proximal phalanx of thumb

main actions: abducts the thumb; aids in opposition

innervation: recurrent branch of median nerve

flexor pollicis brevis

origin: flexor retinaculum and trapezium

insertion: proximal phalanx of thumb

main actions: flexes thumb; aids in opposition

innervation: recurrent branch of median n.

opponens pollicis

origin: flexor retinaculum and trapezium

insertion: lateral side of 1st metacarpal

main actions: opposition

innervation: recurrent branch of median n.

adductor pollicis

origin: 2nd and 3rd metacarpal bones

insertion: medial side of the proximal phalanx of thumb

main actions: adducts thumb, assists opposition

innervation: ulnar n.

abductor digiti minimi

origin: pisiform bone

insertion: medial side of proximal phalanx of digit 5

main actions: abducts digit 5

innervation: ulnar n.

flexor digiti minimi

origin: hamate bone and flexor retinaculum

insertion: medial side of proximal phalanx digit 5

main actions: flexes proximal phalanx of digit 5

innervation: ulnar n.

opponens digiti minimi

origin: hamate and flexor retinaculum

insertion: medial border 5th metacarpal

main actions: opposes 5th digit to thumb

innervation: ulnar n.

lumbricals (4)

origin: tendons of flexor digitorum profundus

insertion: lateral sides of extensor expansion digits 2-5

main actions: flex MCP joints; extend IP joints

innervation: first 2 lumbricals are median n. and the other 2 are ulnar n.

dorsal interossei (4)

origin: adjacent sides of two metacarpal bones

insertion: extensor expansions and base of digits 2-4

main actions: flex MCP joints, extend IP joints; abduct digits 2,3,4

innervation: ulnar n.

palmar interossei

origin: palmar surface of 2nd, 4th and 5th metacarpals

insertion: extensor expansions of digits 2,4, and 5

main actions: flex MCP joints; extend IP joints; adduct digits 2,4,5

innervation: ulnar n.

palmar aponeurosis

origin: palmaris longus tendon

insertion: digits 2-5

main actions: protects deeper structures

innervation: ulnar n.