Extensor pollicis brevis
Arms
Deep muscle — it lies under other muscles. X-ray makes the muscles over it see-through.
- Origin
- Back of the radius and the interosseous membrane
- Insertion
- Base of the proximal phalanx of the thumb
- Action
- Extends the thumb at its base joint
- Nerve supply
- Posterior interosseous nerve (radial nerve, C7–C8)
A short, deep forearm muscle beside the abductor pollicis longus. Their tendons run together across the wrist and form one edge of the anatomical snuffbox.
Extensor pollicis brevis anatomy page →