Background: Accessory muscles in the arm are well-known anatomical variants which have been hypothesized as sources of neurovascular compression syndromes. We report a rare presentation of neuropathy secondary to an accessory biceps aponeurosis causing compression of the median nerve in the antecubital fossa.
Case description: A 65-year-old man presented with a 5-year history of numbness and pain associated with arm flexion. Electromyography was normal and exam revealed mild weakness in the median nerve distribution; however, magnetic resonance imaging demonstrated an accessory biceps tendon overlaying the median nerve in the antecubital fossa. The patient underwent surgical decompression of the median nerve with detachment of the accessory tendon resulting in clinical improvement.
Conclusion: Anomalous biceps musculature should be considered in the workup and treatment of proximal median neuropathy.
Keywords: Accessory biceps; Anomalous musculature; Median nerve; Median neuropathy; Peripheral nerve.
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