Case 10

Abstract Axillary nerve lesions are relatively uncommon peripheral nerve lesions most often encountered after trauma to the shoulder including dislocation and fracture. They are often confused and may be difficult to distinguish clinically from cervical radiculopathy and shoulder joint or tendon pathology, such as rotator cup tear and impingment syndrome. Axillary mononeuropathy may be also a component of neuralgic amyotrophy (acute brachial neuritis, Parsonage-Turner syndrome). This case discusses anatomy of the axillary nerve and highlights the clinical and electrodiagnostic manifestations of axillary mononeuropathy. It also distinguishes axillary nerve lesions from posterior cord brachial plexopathy, upper trunk brachial plexopathy, and C5 and C6 radiculopathies.