Abductor Pollicis Longus
Musculus abductor pollicis longus
Abductor pollicis longus is a deep extensor-compartment muscle that pulls the thumb away from the palm and helps deviate the wrist radially, contributing to the open-hand positioning that underlies pinch grip. Its tendon forms the anterior border of the anatomical snuffbox and is involved, with extensor pollicis brevis, in De Quervain’s tenosynovitis. It is loaded indirectly during thick-bar and pinch-grip training.
- Actions
- Abduction of the thumb at the carpometacarpal joint, Assists thumb extension, Assists wrist radial deviation (abduction)
- Origin
- Posterior surfaces of the proximal ulna and radius and the intervening interosseous membrane
- Insertion
- Radial base of the first metacarpal bone
- Innervation
- Posterior interosseous nerve (C7-C8)
- Blood supply
- Posterior interosseous artery
Antagonists Adductor PollicisOpponens Pollicis