Posterior Full Body View of the Extensor Carpi Ulnaris Muscles

Description

Posteriorly, the extensor carpi ulnaris is visible as a long, slender superficial muscle along the ulnar side of the forearm, arising from the lateral epicondyle of the humerus and posterior border of the ulna and tapering distally toward the ulnar head and wrist. Its belly sits medial to extensor digitorum and lateral to flexor carpi ulnaris across the ulnar border, with the ulna forming the deep bony landmark along its medial aspect. At the distal forearm the tendon courses in the sixth dorsal compartment, lying posterior to the distal ulna and directed toward the base of the fifth metacarpal. This posterior perspective matters when teaching wrist extension and ulnar deviation mechanics because extensor carpi ulnaris shifts from a pure extensor to a stabilizer depending on forearm rotation, acting as a dynamic restraint of the distal radioulnar joint through its subsheath. A common pain generator in racquet sports and golf, extensor carpi ulnaris tendinopathy or subluxation often presents as ulnar sided wrist pain that worsens with resisted extension and ulnar deviation, and it can be assessed with ultrasound or MRI along the ulnar groove. Surgical repair of the ECU subsheath and stabilization procedures rely on clear surface and deep relationships to the distal ulna. Use this artwork in musculoskeletal anatomy courses to anchor the posterior forearm compartment, in sports medicine and hand surgery teaching files discussing ulnar sided wrist pain, and in rehabilitation materials illustrating strengthening or eccentric loading of extensor carpi ulnaris. It also fits well in textbooks that pair surface anatomy with tendon compartment anatomy at the wrist. Anatomical accuracy verified by SciePro's Medical Advisory Board.