Sonographic Representation of Bifid Median Nerve and Persistent Median Artery

Abstract

Bifid median nerve and persistent median arteries are natural anatomic variants that exist in a small percentage of the population. This case describes a young woman who was referred for electrodiagnostic (EDX) testing of her right upper extremity because of a one-year history of numbness, tingling, and discomfort in her right upper extremity consistent with carpal tunnel syndrome. Careful sonographic scanning (gray scale and power Doppler) and dynamic investigation revealed a bifid median nerve and associated persistent median artery (PMA). The awareness of a bifid median nerve and PMA is important when evaluating patients sonographically for diagnosis of upper extremity pathology, including enlargement due to carpal tunnel syndrome. Furthermore, as musculoskeletal sonography increases in clinical practice, it is important to raise awareness of this dual anatomic variant to ensure that appropriate evaluation and treatment are provided. The sonographic presentation of anatomic variations in this case along with a review of these anomalies is provided for translational clinical use.