Upper extremity nerve entrapments: the axillary and radial nerves--clinical diagnosis and surgical treatment.

BACKGROUND: Nontraumatic pain in the shoulder, arm, and hand (brachialgia) is a common complaint in the field of musculoskeletal disorders, where nerve entrapment constitutes a possible cause. The effect of nerve compression is dose-dependent; thus, a low-level compression will only result in decreased endoneurial circulation, neural edema, and a Seddon grade IV weakness, but will not be revealed in nerve conduction or magnetic resonance imaging studies. Because of technical limitations, several clinical options to diagnose compression neuropathies in the upper extremity have been proposed. These include blinded controlled studies on manual muscle testing to delineate the level of nerve compression, and the scratch collapse test to verify the level of compression. In this article, the authors describe the clinical examination and surgical techniques for diagnosing and treating entrapments of the axillary and radial nerves.

METHODS: A previously published clinical triad for diagnosis of nerve compressions has been used: (1) manual muscle testing to reveal weakness in specific muscles distal to the level of nerve compression; (2) pain on compression and/or positive Tinel sign; and (3) positive scratch collapse test at the level of nerve compression.

RESULTS: Detailed videos illustrate the examination techniques for diagnosing axillary entrapment in the shoulder and radial nerve entrapments in the upper arm and forearm (four levels), and the surgical techniques for each nerve release.

CONCLUSION: The clinical triad of muscle testing, scratch-collapse test, and pain at the level of nerve compression provides the clinician with a clinical foundation for analyzing patients with brachialgia in a structured fashion.