The extensor pollicis brevis is a muscle within the deep compartment of the posterior forearm.
The tendon of the extensor pollicis brevis passes through the 1st extensor compartment at the wrist, where it contributes to the radial border of the anatomical snuffbox.
- Attachments: Originates from the posterior surface of the radius and interosseous membrane. It attaches to the base of the proximal phalanx of the thumb.
- Actions: Extension at the metacarpophalangeal and carpometacarpal joints of the thumb.
- Innervation: Radial nerve (posterior interosseous branch).
- Blood supply: Ulnar artery.