Extensor Pollicis Longus, Posterior View

Description

Running obliquely across the dorsal distal radius, the extensor pollicis longus (EPL) tendon is highlighted as it turns around Lister’s tubercle (dorsal tubercle of the radius) and continues distally toward the thumb. The posterior arm and forearm skeleton provides orientation, including the humerus proximally and the radius and ulna in parallel, with the hand bones extending distal to the radiocarpal joint. On the dorsum of the wrist the EPL lies medial to the extensor pollicis brevis and abductor pollicis longus compartment and crosses toward the ulnar side relative to the thumb, defining the medial border of the anatomical snuffbox. A sharp change in direction is the point. Clinically, this posterior view is the one you want when teaching how the third extensor compartment uses Lister’s tubercle as a pulley, a relationship that explains why EPL attritional rupture can follow a nondisplaced distal radius fracture or chronic tenosynovitis. The diagonal course also matters when localizing pain with resisted thumb interphalangeal extension and when planning dorsal wrist incisions, where protecting the EPL and its synovial sheath helps prevent postoperative adhesion and loss of thumb extension. Use this asset in upper limb anatomy labs, hand surgery teaching files, and radiology or orthopedics materials that correlate surface landmarks with the extensor compartments on ultrasound or MRI. It also fits textbook figures contrasting the anatomical snuffbox boundaries and the tendons involved in De Quervain disease versus isolated EPL pathology. Anatomical accuracy verified by SciePro's Medical Advisory Board.