Hand - Intrinsic muscles

Question 1

palmaris brevis

Answer 1

orgin: flexor retinaculum

insertion: demis on the ulnar border

innervation: ulnar nerve

main action: wrinkles the skin of the palm

Question 2

adductor pollicis

Answer 2

origin:
- oblique head: 2nd and 3rd metacarpals and capitates
- transverse head: 3rd metacarpal

insertion: proximal 1st phalange

innervation: ulnar nerve

main action: adduction the thumb

Question 3

lumbricals

Answer 3

4 muscles

origin:
- 1st and 2nd: lateral tendons of flexor digitorum profundus
- 3rd and 4th: medial tendons of flexor digitorum profundus

insertion: lateral side of the dorsal expansion of 2-5

innervation:
- median nerve (1st and 2nd lumbricals)
- ulnar nerve (3rd and 4th lumbricals)

main action:
- flexion of the MCP
- extension of DIP and PIP

Question 4

dorsal interossei

Answer 4

4 muscles

origin: adjacent side of metacarpals

insertion:
- dorsal expansion
- base of 2-4 proximal phalanges

innervation: ulnar nerve

main action:
- abduction of the digits
- flexion of MCP
- extension of IP joint

Question 5

palmar interossei

Answer 5

3 muscles - the 3rd finger does NOT contain this muscle

origin: palmer surface of 2nd, 4th, 5th metacarpal

insertion:
- doral expansion
- base of 2nd, 4th, 5th proximal phalange

innervation: ulnar nerve

main action:
- adduction of the digit towards the center of the hand
- flexion of the MCP
- extension of the IP joints

Question 6

flexor pollicis brevis

Answer 6

thenar muscles

origin:
- deep head: trapezium and flexor retinaculum
- superficial head: trapezoid and capitate

insertion: proximal phalange of the 1st digit

innervation: median nerve

main action: flexion of the 1st digit

Question 7

opponens pollicis

Answer 7

thenar muscles

origin: trapezium and flexor retinaculum

insertion: lateral side of 1st metacarpal

innervation: median nerve

main action: brings 1st digit (thumb) to the center of the palm

Question 8

abductor pollicis brevis

Answer 8

thenar muscles

origin:
- flexor retinaculum
- scaphoid
- trapezium

insertion: proximal 1st phalange

innervation: median nerve

main action: abduction of thumb

Question 9

oppones digiti minimi

Answer 9

hypothenar muscles

origin:
- hook of hamate
- flexor retinaculum

insertion: 5th metacarpal

innervation: ulnar nerve

main action:
lateral rotation of the 5th metacarpal towards the center of the palm

Question 10

abductor digiti minimi

Answer 10

hypothenar muscle

origin:
- pisiform
- tendon of the flexor carpi ulnaris

insertion: proximal 5th phalange

innervation: ulnar nerve

main action: abduction of the 5th digit

Question 11

flexor digiti minimi brevis

Answer 11

hypothenar muscle

origin:
- hook of hamate
- flexor retinaculum

insertion: proximal 5th phalange

innervation: ulnar nerve

main action: flexion of the 5th MCP joint