- Click here for access to the full Anatomy Glossary.
- Right click on the image for a downloadable file of this muscle.
- Use of this artwork requires proper credit to be given (Permission: Dr. Joe Muscolino. www.learnmuscles.com – art work Giovanni Rimasti)
The Abductor Pollicis Longus is in the Deep Layer of the Posterior Compartment of the forearm. It is also a member of the Deep Distal Four Group; the deep distal four group is composed of:
- Abductor pollicis longus
- Extensor pollicis brevis
- Extensor pollicis longus
- Extensor indicis
- Posterior radius and ulna to the thumb.
- Abducts the thumb at the carpometacarpal joint.
- Extends the thumb at the carpometacarpal joint.
- Laterally rotates the thumb at the carpometacarpal joint.
- Radially deviates and flexes the hand at the wrist joint.
- Supinates the forearm at the radioulnar joints.
- The belly of the abductor pollicis longus lies deep in the posterior forearm, but its distal tendon become superficial farther distally.
- The distal tendons of the abductor pollicis longus and extensor pollicis brevis travel together in a common synovial sheath and form the lateral border of the anatomic snuffbox.
- The distal tendons of abductor pollicis longus and extensor pollicis brevis are involved in deQuervain’s syndrome (deQuervain’s stenosing synovitis).