Extensor Carpi Ulnaris, Posterior View

Description

Shown from a posterior aspect of the male forearm and hand, the extensor carpi ulnaris runs along the dorsoulnar border of the ulna, its muscle belly lying medial to extensor digitorum and lateral to flexor carpi ulnaris across the ulnar margin. Distally, its tendon narrows and passes deep to the extensor retinaculum in the sixth dorsal compartment, coursing posterior to the ulnar head and ulnar styloid before inserting on the base of the fifth metacarpal. On the radial side, extensor carpi radialis brevis is highlighted, occupying the deep layer beneath extensor carpi radialis longus and sending its tendon toward the base of the third metacarpal. Landmarks are clear. Dorsal wrist tendons and retinacular bands frame the compartmental anatomy. A posterior view matters because the extensor tendons are organized by the extensor retinaculum into osteofibrous tunnels that guide both function and pathology, and the extensor carpi ulnaris is uniquely tethered across the distal radioulnar joint where forearm rotation can provoke tendon sheath irritation. ECU tendinopathy and subsheath tears are common in racquet and stick sports, and tendon subluxation becomes most symptomatic during supination with ulnar deviation. ECRB deserves attention for lateral epicondylitis, where its proximal origin at the lateral epicondyle and radial collateral ligament complex is a consistent pain generator and a surgical debridement target. Use this plate for upper limb anatomy lab teaching, for orthopaedics and sports medicine lectures on dorsal wrist pain, and for surgical atlases describing the sixth extensor compartment, TFCC related ulnar sided symptoms, and approaches around the ulnar head. It also fits well in radiology teaching files when correlating tendon compartments with ultrasound or axial MR at the level of the distal ulna. Anatomical accuracy verified by SciePro's Medical Advisory Board.