Main Model
99 Extensor polIicis brevis
Origin:
Posterior surface of distal third of radius and interosseous membrane
Insertion:
Dorsal aspect of base of proximal phalanx of thumb
Blood Supply:
Posterior interosseous artery
Innervation:
Posterior interosseous nerve (C7, C8), continuation of deep branch of radial nerve
Main Action:
Extends proximal phalanx of thumb at metacarpophalangeal joint; extends carpometacarpal joint