Muscles of the hand Flashcards
Why are the muscles acting on the hand divided into extrinsic and intrinsic groups?
extrinsic- anterior and posterior compartments of the forearm
intrinsic- muscles located in the hand
what are the Thenar muscles called?
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)
origin of opponent pollicis
tubercle of the trapezium and the associated flexor retinaculum
insertion of opponens pollicis
lateral margin of the metacarpal of the thumb
innervation of opponens pollicis
median nerve
function of opponens pollicis
opposes the thumb, by medially rotating and flexing the metacarpal on the trapezium
origin of abductor pollicis brevis
tubercles of the scaphoid and trapezium and from the associated flexor retinaculum
insertion of abductor pollicis brevis
proximal phalanx of the thumb
innervation of abductor pollicis brevis
median nerve
function of abductor pollicis brevis
abducts the thumb
origin of flexor pollicis brevis
tubercle of the trapezium and the associated flexor retinaculum
insertion of flexor pollicis brevis
base of the proximal phalanx of the thumb
function of flexor pollicis brevis
flexes the metacarpophalangeal (MCP) joint of the thumb
innervation of flexor pollicis brevis
median nerve (the deep head is innervated by the deep branch of the ulnar nerve)
What are the three hypothenar muscles?
opponens digiti minimi, abductor digiti minimi and flexor digiti minimi brevis
origin of opponens digiti minimi
hook of hamate and associated flexor retinaculum
insertion of opponens digiti minimi
medial margin of metacarpal 5
innervation of opponens digiti minimi
ulnar nerve
function of opponens digiti minimi
rotates the metacarpal of the little finger towards the palm, producing opposition