Hand Muscles

Question 0

Opponens pollicis:

Answer 0

O: flexor retinaculum and tubercles of scaphoid and trapezium
I: lateral side of first metacarpal
N: recurrent branch of median nerve (C8, T1)
A: to oppose thumb, it draws first metacarpal medially to center of the pal and rotates it medially

Question 1

What muscles make up the thenar muscles?

Answer 1

opponens pollicis, abductor pollicis brevis, flexor pollicis brevis, and adductor pollicis

Question 2

abductor pollicis brevis:

Answer 2

O: flexor retinaculum and tubercles of scaphoid and trapezium
I: lateral side of base of proximal phalanx of the thumb
N: recurrent branch of median nerve (C8, T1)
A: abducts thumb and help oppose it

Question 3

flexor pollicis brevis:

Answer 3

Superficial and Deep head
O: flexor retinaculum and tubercles of scaphoid and trapezium
I: lateral side of the base of proximal phalanx of the thumb
N: recurrent branch of the median nerve (C8, T1)
A: flexes the thumb

Question 4

adductor pollicis:

Answer 4

Oblique head and transverse head
O: Oblique head originates at the base of the 2nd and 3rd metacarpals, capitate and adjacent carpals
transverse head originates at the anterior surface of the shaft of 3rd metacarpal
I: medial side of base of phalanx of the thumb
N: deep branch of ulnar nerve (C8, T1)
A: adducts the thumb towards the lateral border of the thumb

Question 5

What muscles make up the hypothenar muscles?

Answer 5

abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi

Question 6

abductor digiti minimi:

Answer 6

O: Pisiform
I: medial side of base of proximal phalanx of the 5th finger
N: deep branch of the ulnar nerve (C8, T1)
A: abducts the 5th finger and assists in flexion of the proximal phalanx

Question 7

flexor digiti minimi brevis:

Answer 7

O: hook of hamate and flexor retinaculum
I: medial side of base of proximal phalanx of the 5th finger
N: deep branch of ulnar nerve (C8, T1)
A: flexes proximal phalanx of 5th finger

Question 8

opponens digiti minimi:

Answer 8

O: hook of hamate and flexor retinaculum
I: medial border of 5th metacarpal
N: deep branch of ulnar nerve (C8, T1)
A: draws 5th metacarpal anterior and rotates it, bringing finger into opposition with the thumb

Question 9

what muscles make up the short muscles of the hand?

Answer 9

Lumbricals 1 and 2, lumbricals 3 and 4, dorsal interossei 1-4, and palmar interossei 1-3

Question 10

lumbricals 1 and 2

Answer 10

O: lateral 2 tendons of flexor digitorum profundus (as unipennate muscles)
I: lateral sides of extensor expansions of 2nd-5th fingers
N: median nerve (C8, T1)
A: flex MCP joints, extend IP joints of 2nd-5th fingers

Question 11

Lumbricals 3 and 4

Answer 11

O: medial 3 tendons of flexor digitorum profundus (as bipennate muscles)
I: lateral sides of extensor expansions of 2nd-5th fingers
N: median nerve (C8, T1)
A: flex MCP joints and extend IP joints of 2nd-5th fingers

Question 12

Dorsal interossei 1-4

Answer 12

O: adjacent sides of two metacarpals (as bipennate muscles)
I: bases of proximal phalanges, extensor expansions of 2nd-4th fingers
N: deep branch of ulnar nerve (C8, T1)
A: abduct 2nd-4th fingers from axial line (middle finger); act with lumbricals in flexing MCP joints and extending IP joints

Question 13

palmer interossei 1-3

Answer 13

O: palmar surfaces of 2nd, 4th, and 5th metacarpals (as unipennate muscles)
I: bases of proximal phalanges; extensor expansions of 2nd, 4th, and 5th fingers
N: deep branch of ulnar nerve (C8, T1)
A: adduct 2nd, 4th, and 5th fingers toward axial line; assists lumbricals in flexing MCP joints and extending IP joints