Muscles of the hand

Question 0

Abductor pollicis brevis

Answer 0

O: Flexor retinaculum, scaphoid bone, trapezium bone
I: Proximal phalanx of the thumb
A: Abducts the thumb
N: Median nerve

Question 1

Thenar muscles

Answer 1

• Abductor pollicis brevis
• Flexor pollicis brevis
• Opponens pollicis

Question 2

Flexor pollicis brevis

Answer 2

O: Flexor retinaculum, scaphoid bone, trapezium bone
I: Proximal phalanx of the thumb
A: Flexes the thumb
N: Median nerve

Question 3

Opponens pollicis

Answer 3

O: Flexor retinaculum, scaphoid bone, trapezium bone
I: 1st metacarpal
A: opposes the thumb (bringing thumb to pinky)
N: Median nerve

Question 4

Hypothenar muscles

Answer 4

• Abductor digiti minimi
• Flexor digiti minimi
• Opponens digiti minimi

Question 5

Abductor digiti minimi

Answer 5

O: Pisiform bone
I: Proximal phalanx of the 5th digit
A: Abducts the pinky
N: Ulnar nerve

Question 6

Flexor digiti minimi

Answer 6

O: Flexor retinaculum and hook of the hamate
I: Proximal phalanx of the 5th digit
A: Flexes the pinky
N: Ulnar nerve

Question 7

Opponens digiti minimi

Answer 7

O: Flexor retinaculum and hook of the hamate
I: 5th metacarpal
A: Opposes the pinky (bringing the pinky to the thumb)
N: Ulnar nerve

Question 8

Adductor pollicis

Answer 8

O: Oblique head originates from the 2nd & 3rd metacarpals and the capitate bone
Transverse head originates from the 3rd metacarpal
I: Both insert onto the proximal phalanx of the thumb
A: Adducts the thumb
N: Ulnar nerve

Question 9

Lumbricals

Answer 9

O: Tendons of flexor digitorum profundus
I: Dorsal expansions
A: Flex the MCP joint, extent IP joints (with some help from the interossei), ‘tata’ movement
N: Lumbricals 1, 2 are innervated by the median nerve
Lumbricals 3,4 are innervated by the ulnar nerve
**Flexor pollicis longus does not have a lumbrical
**Little muscles with no bone attachment

Question 10

Dorsal interossei

Answer 10

O: Metacarpals
I: Bases of proximal phalanges via the dorsal expansions
A: Abduct fingers from midline, 1st dorsal interosseus and adduction pollicis both act to clench thumb against index finger for strong pinching action
N: Ulnar nerve

Question 11

Palmar interossei

Answer 11

O: Metacarpals
I: Bases of proximal phalanges via the dorsal expansions
A: Adduct fingers toward midline
N: Ulnar nerve