Extensor Carpi Ulnaris Under the Skin, Medial View

Description

Running along the ulnar border of the distal forearm, the extensor carpi ulnaris (ECU) is shown just deep to the male skin, its muscle belly tapering into a distinct tendon as it approaches the wrist. Medial to the radius and closely applied to the posterior aspect of the ulna, the ECU sits posterior to the flexor carpi ulnaris and superficial to the ulnar head in the distal segment. Distally, its tendon courses beneath the extensor retinaculum in the sixth dorsal compartment and continues toward its insertion at the base of the fifth metacarpal. Subcutaneous landmarks are emphasized. Ulnar-sided wrist pain often localizes to the ECU tendon and its sheath, and a medial oblique view like this helps clarify why snapping or subluxation occurs when the subsheath is torn and the tendon displaces during supination with ulnar deviation. Surgical repair and tenosynovectomy depend on respecting the tendon’s relationship to the ulnar groove and the retinacular constraints that form the sixth compartment. It also frames the ECU as a functional partner, and sometimes confounder, when differentiating tendinopathy from triangular fibrocartilage complex (TFCC) injury in athletes and manual workers. Use this artwork in upper limb anatomy teaching to connect surface anatomy to the deep extensor compartments, or in sports medicine and hand surgery materials discussing ECU tendinosis, tenosynovitis, and instability. It also fits well in rehabilitation protocols and patient education sheets that explain why resisted wrist extension with ulnar deviation provokes symptoms and how bracing limits provocative motion. Anatomical accuracy verified by SciePro's Medical Advisory Board.