Muscles of the hand

Question 1

Why are the muscles acting on the hand divided into extrinsic and intrinsic groups?

Answer 1

extrinsic- anterior and posterior compartments of the forearm
intrinsic- muscles located in the hand

Question 2

what are the Thenar muscles called?

Answer 2

Opponens pollicis, abductor pollicis brevis, flexor pollicis brevis
(the muscle bellies produce a buldge know as the themas eminence at the base of the thumb)

Question 3

origin of opponent pollicis

Answer 3

tubercle of the trapezium and the associated flexor retinaculum

Question 4

insertion of opponens pollicis

Answer 4

lateral margin of the metacarpal of the thumb

Question 5

innervation of opponens pollicis

Answer 5

median nerve

Question 6

function of opponens pollicis

Answer 6

opposes the thumb, by medially rotating and flexing the metacarpal on the trapezium

Question 7

origin of abductor pollicis brevis

Answer 7

tubercles of the scaphoid and trapezium and from the associated flexor retinaculum

Question 8

insertion of abductor pollicis brevis

Answer 8

proximal phalanx of the thumb

Question 9

innervation of abductor pollicis brevis

Answer 9

median nerve

Question 10

function of abductor pollicis brevis

Answer 10

abducts the thumb

Question 11

origin of flexor pollicis brevis

Answer 11

tubercle of the trapezium and the associated flexor retinaculum

Question 12

insertion of flexor pollicis brevis

Answer 12

base of the proximal phalanx of the thumb

Question 13

function of flexor pollicis brevis

Answer 13

flexes the metacarpophalangeal (MCP) joint of the thumb

Question 14

innervation of flexor pollicis brevis

Answer 14

median nerve (the deep head is innervated by the deep branch of the ulnar nerve)

Question 15

What are the three hypothenar muscles?

Answer 15

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

Question 16

origin of opponens digiti minimi

Answer 16

hook of hamate and associated flexor retinaculum

Question 17

insertion of opponens digiti minimi

Answer 17

medial margin of metacarpal 5

Question 18

innervation of opponens digiti minimi

Answer 18

ulnar nerve

Question 19

function of opponens digiti minimi

Answer 19

rotates the metacarpal of the little finger towards the palm, producing opposition

Question 20

origin of abductor digiti minimi

Answer 20

pisiform and tendon of the flexor carpi ulnaris

Question 21

insertion of abductor digiti minimi

Answer 21

base of the proximal phalanx of the little finger

Question 22

innervation of abductor digiti minimi

Answer 22

ulnar nerve

Question 23

function of abductor digit minimi

Answer 23

abducts the little finger

Question 24

origin of flexor digiti minimi brevis

Answer 24

hook of hamate and adjacent flexor retinaculum

Question 25

insertion of flexor digit minimi brevis

Answer 25

base of the proximal phalanx of the little finger

Question 26

innervation of flexor digiti minimi brevis

Answer 26

ulnar nerve

Question 27

function of flexor digit minimi brevis

Answer 27

flexes the MCP joint of the little finger

Question 28

what are the four lumbricals

Answer 28

unipennate (I), unipennate (II), bipennate (III) and bipennate (IV)

Question 29

origin of the lumbricals

Answer 29

each tendon of the flexor digitorum profundus

Question 30

insertion of the lumbricals

Answer 30

they pass dorsally and laterally around each finger and inserts into the extensor hood

Question 31

function of the lumbricals

Answer 31

flexion at the MCP joint and extension at the interphalangeal joints of each digit

Question 32

innervation of the lumbricals

Answer 32

the lateral two lumbricals (index and middle)= median nerve | the medial two lumbricals (little and ring finger)= ulnar nerve

Question 33

What are the two interossei muscles called?

Answer 33

dorsal interossei (4) and palmar interossei (3)

Question 34

origin of the dorsal interossei

Answer 34

lateral and medial surfaces of the metacarpals

Question 35

insertion of dorsal interossei

Answer 35

extensor hood and proximal phalanx of each finger

Question 36

innervation of dorsal interossei

Answer 36

ulnar nerve

Question 37

function of dorsal interossei

Answer 37

abduct the fingers at the MCP joint

Question 38

origin of palmar interossei

Answer 38

medial or lateral surface of a metacarpal

Question 39

insertion of palmar interossei

Answer 39

extensor hood and proximal phalanx of the same finger

Question 40

innervation of the palmar interossei

Answer 40

ulnar nerve

Question 41

function of palmar interossei

Answer 41

aducts the fingers at the MCP joint

Question 42

origin of palmaris brevis

Answer 42

palmar aponeurosis and flexor retinaculum

Question 43

insertion of palmaris brevis

Answer 43

dermis of the skin on the medial margin of the hand

Question 44

innervation of palmaris brevis

Answer 44

ulnar nerve

Question 45

function of palmaris brevis

Answer 45

wrinkles the skin of the hypothenar eminence and deepens the curvature of the hand, improving the grip

Question 46

origin of adductor pollicis

Answer 46

one head originates from metacarpal 3. the other head originates from the capitate and adjacent areas of metacarpals 2 and 3

Question 47

insertion of adductor pollicis

Answer 47

the base of the proximal phalanx of the thumb

Question 48

innervation of adductor pollicis

Answer 48

ulnar nerve

Question 49

function of adductor pollicis

Answer 49

adductor of the thumb