MuscleForearm — posterior (deep)
Abductor pollicis longus
Latin: M. abductor pollicis longus
Location: Forearm
View the abductor pollicis longus in 3DOrigin
Posterior surfaces of the ulna, radius and interosseous membrane.
Insertion
Base of the first metacarpal (and trapezium slip).
Action
Abducts and extends the thumb's carpometacarpal joint — opening the web for grasp.
Nerve supply
Posterior interosseous nerve (C7–C8).
Blood supply
Posterior interosseous artery.
Clinical relevance
With extensor pollicis brevis it crosses the wrist extensors — the first dorsal compartment inflamed in de Quervain's tenosynovitis of new mothers.
Educational anatomy reference, not medical advice. About this content.