Posterior Forearm Flashcards
What are the two major functions of muscles in the posterior forearm?
Supination and extension
What nerve innervates all the muscles of the posterior forearm?
The radial nerve
State the origin and insertion of Brachioradialis and its function
It originates from the lateral supracondylar ridge and it inserts onto the lateral surface of the distal radius. It is an accessory flexor of the forearm at the elbow.
Name the seven muscles of the superficial layer of the posterior forearm.
Brachioradialis, extensor Carpi radialis longus, extensor Carpi ulnaris brevis, extensor digitorum, extensor digiti minimi, extensor Carpi ulnaris, anconeus
Where so all the superficial muscles of the posterior forearm originate?
The lateral epicondyle of the humerus.
State the insertion of extensor carpi radialis longus and brevis
The dorsal aspect of the hand at the base of the metacarpals. Longus inserts into II and brevis inserts into II and III
Into which phalanges does extensor digitorum insert?
The distal and middle phalanges of the four lateral digits.
What is the function of anconeus?
Abduction of the ulna in pronation and accessory extensor of the elbow.
What are the five deep muscles of the posterior forearm?
Supinator, extensor pollicis longus, extensor pollicis brevis, abductor pollicis longus, extensor indicis.
Name the muscles which originate from the posterior surface of the ulna.
Extensor pollicis longus, extensor indicis, abductor pollicis longus
Where does extensor pollicis brevis originate?
Posterior surface of the radius.
What tendons form the boundaries of the anatomical snuffbox?
Abductor pollicis longus and extensor pollicis brevis on the lateral side and on the medial side extensor pollicis longus.
State the difference in function between extensor pollicis longus and extensor pollicis brevis.
Brevis can extend the carpometacarpal joint and the metacarpalphalangeal joint. Longus can e tend both of these joints and the distal interphalangeal joint.
State the origins and attachments of Supinator.
Supinator crest of ulnar and the lateral surface of radius superior to the oblique line.
Where on the thumb does abductor pollicis longus attach?
It attaches to the lateral side of the metacarpal.
