Extensor pollicis brevis

Origin	Radius
Insertion	Thumb, proximal phalanx
Action(s)	Extension of thumb at metacarpophalangeal joint
Nerve Supply	Posterior interosseous nerve
Arterial Supply	Posterior interosseous artery
Physical Exam
Clinical Importance
Disease States
Discussion	Absence; fusion of tendon with that of the Extensor pollicis longus. It arises from the dorsal surface of the body of the radius below that muscle, and from the interosseous membrane. Its direction is similar to that of the Abductor pollicis longus, its tendon passing the same groove on the lateral side of the lower end of the radius, to be inserted into the base of the first phalanx of the thumb.