intrinsic hand muscles OIA

Question 1

palmaris brevis

Answer 1

O: flexor retinaculum and palmar aponeurosis
I: dermis of ulnar border of hand
A: wrinkles the skin of the palm

Question 2

abductor pollicis brevis

Answer 2

O: flexor retinaculum (lateral edge), scaphoid tubercle, trapezium tubercle
I: lateral side of base of proximal phalanx of thumb, dorsal digital expansion
A: abduction of thumb @ CMC, weak flexion of thumb @ MCP, weak extension of thumb @ CMC and IP joints

Question 3

flexor pollicis brevis

Answer 3

O: flexor retinaculum and trapezium
I: lateral side of base of proximal phalange of thumb
A: flexion of thumb @ CMC and MCP joints. weak abduction of thumb @ CMC

Question 4

opponens pollicis

Answer 4

O: flexor retinaculum and trapezium
I: anterior surface and radial border of 1st metacarpal
A: opposition of thumb @ CMC. weak flexion, medial rotation, abduction of thumb @ CMC

Question 5

adductor pollicis

Answer 5

O: transverse head - 3rd metacarpal (anterior distal shaft). oblique head - 2nd and 3rd metacarpal (proximal shaft).
I: transverse head - proximal phalange of thumb. oblique head - base of proximal phalange of thumb, dorsal digital expansion
A: adduction of thumb @ CMC. weak flexion of thumb @ CMC and MCP. weak extension of thumb @ IP

Question 6

opponens digiti minimi

Answer 6

O: flexor retinaculum and hook of hamate
I: anterior shaft of 5th metacarpal (ulnar border)
A: opposes 5th finger @ CMC joint. weak flexion of thumb @ CMC and MCP joint. weak extension of thumb @ IP

Question 7

flexor digiti minimi

Answer 7

O: flexor retinaculum and hook of hamate
I: anterior base of proximal phalange of 5th finger
A: flexion of 5th finger @ MCP. weak flexion of finger @ CMC.

Question 8

abductor digiti minimi

Answer 8

O: pisiform, tendon of flexor carpi ulnaris
I: base of 5th proximal phalange (ulnar side), dorsal digital expansion
A: abduction of 5th finger @ MCP, weak abduction of 5th finger @ CMC, weak flexion of 5th finger @ MCP, CMC, weak extension of 5th finger @ PIP, DIP