Abductor Pollicis Longus Wrist Tendon

tendo musculi abductoris pollicis longi ad carpum

The abductor pollicis longus tendon passes through the first extensor compartment at the wrist alongside the extensor pollicis brevis, crossing over the radial wrist extensors to insert onto the radial base of the first metacarpal. Multiple tendon slips (2-4) of APL are frequently present and may occupy separate sub-compartments within the first compartment.

Region: Forearm

Clinical Relevance

Clinical Notes

APL has the highest tendon slip variability of any forearm muscle — 2-4 slips are common and may occupy separate sub-compartments that require individual release in de Quervain surgery. The APL tendon at wrist level is the primary structure tensioned in the Finkelstein test. In scaphoid fracture surgery, the APL insertion at the first metacarpal base and its crossing over the wrist extensors creates the anatomical basis for the radial approach to the scaphoid.

Pathology

Common Injuries & Conditions

APL Sub-compartment Septum

Fibrous septa within the first extensor compartment creating separate APL and EPB tunnels, producing incomplete relief from de Quervain surgery if both sub-compartments are not released, a common cause of failed first compartment decompression.