Posterior Forearm Flashcards
how many muscles are there in the superficial layer of the posterior compartment of the forearm?
6 (in sheffield, 7 in leicester - anconeus)
which nerve innervates all muscles in the posterior forearm?
radial nerve
what is the general action of the posterior compartment of the forearm?
extension
where is the common extensor origin?
lateral epicondyle of the humerus
which 4 muscles come off the common extensor origin?
extensor carpi radialis brevis
extensor digitorum
extensor carpi ulnaris
extensor digiti minimi
what are the attachments of the brachioradialis?
humerus
distal radius
what is the action of brachioradialis?
FLEXOR at elbow
which aspect of the forearm do the ECRL and ECRB muscles run down? what action does this enable them to produce?
lateral aspect - abduction at wrist
what is the action of extensor carpi radialis longus?
abduction and extension at wrist
what is the action of extensor carpi radialis brevis?
abduction and extension at wrist
which muscle is the main extensor of fingers (at MCP and IP!)
extensor digitorum
what is the action of extensor digitorum?
extension of fingers at MCP and IP joints
what are the attachments of extensor digitorum?
lateral epicondyle
extensor hood of each finger
what are the attachments of extensor digiti minimi?
lateral epicondyle
extensor hood of little finger
what is the action of extensor digiti minimi?
extends little finger
contributes to wrist extension
along which aspect of forearm does extensor carpi ulnaris lie? what action does this position enable it to produce?
medial aspect
adduction at wrist
what is the action of extensor carpi ulnaris?
adduction and extension at wrist
name the 6 muscles of the superficial layer of the posterior compartment of the forearm?
brachioradialis extensor carpi radialis longus + brevis extensor digitorum extensor digiti minimi extensor carpi ulnaris
(bonus for leicester: anconeus)
how many muscles are there in the deep layer of the posterior compartment of the forearm?
5
how many muscles are there in the posterior forearm?
11 - 5 in deep, 6 in superficial
which digits do most of the deep muscles of the posterior compartment of the forearm act upon?
thumb and index finger (all but supinator)
where in the cubital fossa does the supinator lie?
the floor
what structure passes between the two heads of the supinator?
deep branch of radial nerve
what are the attachments of the supinator?
two heads: lateral epicondyle / posterior surface of ulna
attach to posterior surface of radius
to which border of the anatomical snuffbox does the abductor pollicis longus tendon contribute?
lateral
which tendons contribute to the lateral border of the anatomical snuffbox?
abductor pollicis longus and extensor pollicis brevis
what is the action of abductor pollicis longus
abducts thumb
to which border of the anatomical snuffbox does the extensor pollicis brevis tendon contribute?
lateral
what is the action of the extensor pollicis brevis?
extends thumb at MCP + carpometacarpal joints of thumb
to which border of the anatomical snuffbox does the extensor pollicis longus tendon contribute?
medial
what is the action of the extensor pollicis longus?
extends all thumb joints - carpometacarpal, MCP and IP
what is the action of extensor indicis?
extends index finger - allows independent movement of index finger when extended
name the 5 muscles of the deep layer of the posterior compartment of the forearm
supinator abductor pollicis longus extensor pollicis brevis extensor pollicis longus extensor indicis
