Intrinsic muscles of hand Flashcards
What are the muscles present in the first layer of hand?
Abductor pollicis longus
flexor pollicis brevis
abductor digiti minimi
flexor digiti minimi
Attachments and actions of abductor pollicis longus
origin: FR, scaphoid, trapezium
insert: proximal phalanx of thumb, lateral sesamoid of thumb
action: abduct thumb, rotate medially
Attachments and actions of flexor pollicis brevis
origin: FR, trapezium, capitate, trapezoid
insert: proximal phalanx of thumb, lateral sesamoid of thumb
action: flex thumb at MCP, CMC and rotate medially
Attachments and actions of abductor digiti minimi
origin: pisiform, flexor carpi ulnaris tendon
insert: proximal phalanx of 5th digit
action: abduct little finger away from ring finger
Attachments and actions of flexor digiti minimi
origin: FR, hook of hamate
insert: proximal phalanx of 5th digit
action: flex little finger at MCP
What muscles are present in layer 2 of hand? What are its attachments and actions?
lumbricals
origin: tendons of flexor digitorum profundus
insert: dorsal digital expansion of fingers
action: extend at IP when MCP is flexed
What muscles are present in layer 3 of hand?
opponens pollicis
adductor pollicis
opponens digiti minimi
Attachments and actions of opponens pollicis
origin: FR, trapezium
insert: lateral border of 1st metacarpal
action: flex thumb at MCP, rotate medially across palm
Attachments and actions of adductor pollicis (transverse and oblique)
origin: capitate + 2&3 metacarpal
insert: proximal phalanx of thumb, medial sesamoid of 1st MCP joint
action: adducts thumb to palm (greatest advantage: abducted, flexed and rotated - holding piece of paper), flex MCP and extend IP
Attachments and actions of opponens digiti minimi
origin: FR, hook of hamate
insert: 5th metacarpal
action: pulls 5th digit upwards and rotates in laterally (little finger meets thumb - in opposition)
What are the muscles present in layer 4 of hand?
interossei - palmar and dorsal
What is the palmar interossei? Attachments and actions?
action: it moves digits closer to midline (adduction of fingers)
origin: anterior border of MC 2, 4, 5
insert: proximal phalanx of corresponding digit
Attachments and actions of dorsal interossei?
action: abduction of fingers - bringing digits away from midline
origin: sides of adjacent MC
insert: proximal phalanx of 2-5
What is the nerve supply to different muscle groups?
Median Nerve:
recurrent - abductor pollicis brevis, flexor pollicis brevis, opponens pollicis
lateral - 1st and 2nd lumbricals
Ulnar nerve:
deep - abductor digiti minimi, flexor digiti minimi, opponens digiti minimi, adductor pollicis, 3 4 lumbricals, interossei
