Abductor pollicis longus
Arms
Deep muscle — it lies under other muscles. X-ray makes the muscles over it see-through.
- Origin
- Back of the ulna and radius and the interosseous membrane
- Insertion
- Base of the first metacarpal
- Action
- Abducts and extends the thumb; helps bend the wrist toward the thumb side
- Nerve supply
- Posterior interosseous nerve (radial nerve, C7–C8)
A deep forearm muscle whose tendon crosses the wrist to the thumb. With the extensor pollicis brevis it forms the front edge of the hollow at the base of the thumb (the anatomical snuffbox).
Abductor pollicis longus anatomy page →