Dislocation of the Medial Head of the Triceps With Ulnar Nerve Location Anterior to the Medial Epicondyle.

Snapping elbow is a rare syndrome caused by dislocation of the medial head of the triceps. Simultaneous dislocation of the ulnar nerve occurs even less frequently. We report a case of ulnar nerve dislocation accompanied by dislocation of the triceps over the medial humeral epicondyle. The ulnar nerve was located in front of the medial epicondyle and did not change position with the elbow flexed or extended. At the point of insertion, the proximal end of the triceps muscle was displaced anteriorly. In this case, diagnosis by physical examination was challenging, but ultrasonography proved useful for diagnosis. During surgical treatment, partial resection of the triceps medial head was achieved, and the patient demonstrated a full recovery.