Extensor pollicis brevis

Anatomy

Origin:
Posterior of distal radius and adjacent Interosseus membrane.

Insertion:
Dorsal surface of base of proximal phalanx of thumb.

Key Relations:
-Its tendon together with the tendon of abductor pollicis longus forms the anterior boundary of the anatomical snuff box.
-One of the six muscles in the deep posterior compartment of the forearm.

Functions

-Extends the thumb at the carpometacarpal and metacarpophalangeal joints
-Abducts the thumb at the carpometacarpal and metacarpophalangeal joints

e.g. to give somthing the thumbs up / approve of an idea..

Supply

Nerve Supply:
Posterior Interosseous nerve (C7,C8) (continuation of deep branch of radial nerve).

Blood Supply:
Posterior Interosseous artery.

Clinical

Is affected in radial nerve palsy.

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