Examination of a Patient with Deep Motor Branch Ulnar Neuropathy

Mackinnon SE1 Yee A1

March 20, 2018

Examination of patients with distal ulnar compressive neuropathy requires a systematic approach to eliminate proximal issues from the diagnosis. Through a proximal to distal approach by examining the hand for motor/sensory and extrinsic/intrinsic function and median/ulnar nerves allows the examiner to pinpoint the level of neuropathy. In this case, we present a 62-year old patient with complaints of mild cubital tunnel syndrome, but significant intrinsic ulnar neuropathy. During examination, first dorsal interosseous muscle wasting was observed as compared to good ulnar nerve sensation and extrinsic function. In the examination video, the examiner makes a diagnosis of compression of the deep motor branch of the ulnar nerve through this systematic proximal to distal approach. The examiner also corroborates their findings with provocative tests which includes the scratch collapse test. Surgical management included release of the deep motor branch, where two branches were observed and separated by a large bony anatomical anomaly (hook of the hamate). An ulnar nerve transposition was elected due the clinical findings of some ulnar paresthesia and minor subluxation of the ulnar nerve and electrodiagnostic findings of a conduction block at the elbow. This patient workup is also detailed in the lecture video and provides the background for the following examination video.