Neuralgic amyotrophy manifested by severe axillary mononeuropathy limited only to the anterior branch

INTRODUCTION: In this study we describe a case demonstrating clinical, radiographic, electrophysiologic, and surgical evidence of a restricted but severe anterior branch axillary nerve mononeuropathy due to neuralgic amyotrophy (NA). METHODS: On each diagnostic modality there was severe involvement of the anterior and lateral deltoid muscle with sparing of the posterior deltoid and teres minor muscles and cutaneous innervation to the skin overlying the lateral shoulder. RESULTS: No structural etiologies were discovered during surgical exploration. CONCLUSIONS: This case provides another unique manifestation of NA and augments the theory of selective fascicular vulnerability.