muscles of the hand

Question 0

flexor pollicis brevis

Answer 0

Origin: superficial head and deep head: flexor retinaculum and tubercles of scaphoid and trapezium
Insertion: lateral side of base of proximal phalanx of thumb
Innervation: recurrent branch of median nerve (C8, T1)
Action: flexes thumb

Question 1

abductor pollicis brevis

Answer 1

Origin: flexor retinaculum and tubercles of scaphoid and trapezium
Insertion: lateral side of base of proximal phalanx of thumb
Innervation: recurrent branch of median nerve (C8, T1)
Action: abducts thumb; helps oppose it

Question 2

opponens pollicis

Answer 2

Origin: flexor retinaculum and tubercles of scaphoid and trapezium
Insertion: lateral side of 1st metacarpal
Innervation: recurrent branch of median nerve (C8, T1)
Action: to oppose thumb, its draws 1st metacarpal medially to center of palm and rotates it medially

Question 3

adductor pollicis

Answer 3

Origin: oblique head: base of 2nd and 3rd metacarpals, capitate, adjacent carpals
transverse head: anterior surface of shaft of 3rd metacarpal
Insertion: medial side of base of proximal phalanx of thumb
Innervation: deep branch of ulnar nerve (C8, T1)
Action: adducts thumb toward lateral border of palm

Question 4

abductor digiti minimi

Answer 4

Origin: pisiform
Insertion: medial side of base of proximal phalanx of 5th finger
Innervation: deep branch of ulnar nerve (C8, T1)
Action: abducts 5th finger; assists in flexion of its proximal phalanx

Question 5

flexor digiti minimi brevis

Answer 5

Origin: hook of hamate and flexor retinaculum
Insertion: medial side of base of proximal phalanx of 5th finger
Innervation: deep branch of ulnar nerve (C8, T1)
Action: flexes proximal phalanx of 5th finger

Question 6

opponens digiti minimi

Answer 6

Origin: hook of hamate and flexor retinaculum
Insertion: medial border of 5th metacarpal
Innervation: deep branch of ulnar nerve (C8, T1)
Action: draws 5th finger anterior and rotates it, bringing 5th finger into opposition with thumb

Question 7

lumbricals (1 and 2)

Answer 7

Origin: lateral 2 tendons of flexor digitorum profundus (as unipennate muscles)
Insertion: lateral sides of extensor expansions of 2nd-5th fingers
Innervation: median nerve (C8, T1)
Action: flex metacarpophalangeal joints; extend interphalangeal joints of 2nd-5th fingers

Question 8

lumbrical (3 and 4)

Answer 8

Origin: medial 3 tendons of flexor digitorum profundus (bipennate muscles)
Insertion: lateral sides of extensor expansions of 2nd-5th fingers
Innervation: deep branch of ulnar nerve (C8, T1)
Action: flex metacarpophalangeal joints; extend interphalangeal joints of 2nd-5th fingers

Question 9

dorsal interossei (1-4)

Answer 9

Origin: adjacent sides of 2 metacarpals (as bipennate muscles)
Insertion: bases of proximal phalanges; extensor expansions of 2nd-4th fingers
Innervation: deep branch of ulnar nerve (C8, T1)
Action: abduct 2nd-4th fingers from axial line; act with lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints

Question 10

palmar interossei

Answer 10

Origin: palmar surfaces of 2nd, 4th, and 5th metacarpals (as unipennate muscles)
Insertion: bases of proximal phalanges; extensor expansions of 2nd, 4th, and 5th fingers
Innervation: deep branch of ulnar nerve (C8, T1)
Action: Adduct 2nd, 4th, and 5th fingers toward axial line; assist lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints