A Posterior View of the Abductor Pollicis Longus Muscle of a Male

Description

Arising from the posterior surfaces of the radius and ulna and the adjacent interosseous membrane, the abductor pollicis longus occupies the deep posterior compartment of the forearm, lying inferior to the lateral epicondylar region and coursing distally toward the dorsolateral wrist. Its tendon passes laterally across the dorsal aspect of the distal radius, then angles toward the base of the first metacarpal on the radial side of the thumb, immediately superficial to the carpal bones. The radius lies lateral (thumb side) to the ulna in anatomical position, and the tendon’s trajectory is read in relation to that bony axis. Bone landmarks are clear. This posterior perspective matters because the abductor pollicis longus tendon forms the lateral border of the anatomical snuffbox and runs within the first dorsal extensor compartment beneath the extensor retinaculum, a frequent site of stenosing tenosynovitis (de Quervain disease) in patients with radial-sided wrist pain aggravated by thumb abduction or gripping. Surgeons and radiologists also use this tendon as a surface guide when planning or interpreting interventions around the radial styloid, the dorsal radial sensory nerve, and the radial artery as it curves toward the first intermetacarpal space. Misidentifying the tendon is easy when the neighboring extensor pollicis brevis is not distinguished. Orientation solves that. Use this asset for upper limb anatomy teaching on the posterior forearm, for hand surgery and sports medicine publications discussing de Quervain release and first dorsal compartment anatomy, and for radiology education aligning tendon course with osseous landmarks on ultrasound or MRI. Anatomical accuracy verified by SciePro's Medical Advisory Board.