RESUMEN
<p><b>OBJECTIVES</b>To investigate anatomical mechanism of the ulnar wrist pain caused by the compression of the dorsal branch of the ulnar nerve, and discuss the diagnosis and treatment of the compression.</p><p><b>METHODS</b>40 sides of the upper extremities of adult cadavers were studied anatomically. The dorsal branch of the ulnar nerve and its relationship to the surroundings was dissected and observed grossly and microscopically. 13 cases of the compression of the dorsal branch of the ulnar nerve were treated and followed up.</p><p><b>RESULTS</b>The dorsal branch of the ulnar nerve was penetrated from the deep of the flexor carpi ulnaris muscle 5.6 approximately 6.8 cm proximally from the styloid process of the ulna, then ran along the ulna and divided into 2 approximately 3 big branches at the medial side of the head of the ulna. The transverse branch was apt to injury during wrist movement as it crossed or rounded the head of the ulna where it was close to the peristeam. Seven of 13 cases of the compression of the dorsal branch of the ulnar nerve were treated by local block, and 6 by surgical neurolysis. Nine cases of this group got showed good effect without recurrence after 4 months to 1 year follow-up.</p><p><b>CONCLUSION</b>The anatomical basis of the compression of the dorsal branch of the ulnar nerve is repetitive traction to this nerve during wrist movement, and the compression of the transverse branch is the main cause of ulnar wrist pain. The compression of the dorsal branch of the ulnar nerve should be considered to the patients with ulnar wrist pain and abnormal sensation along the dorsal ulnar side of hand.</p>