Rare communication between the musculocutaneous and median nerves in the forearm: its clinical significance.

Abstract

Morphologic classifications of communication between musculocutaneous and median nerves are not based on the distribution and the function of the communicating branch. The authors report a rare case of such a communication with passage of the median nerve through the pronator teres muscle and discuss its clinical significance. The musculocutaneous nerve was divided into a lateral branch that continued to the lateral antebrachial cutaneous nerve and a medial branch that joined the median nerve in the forearm. The authors separated the nerve bundles and noted that the communicating branch derived from the sixth to seventh cervical nerves and supplied nerve fibers to the pronator teres muscle and the proper palmar digital nerve of the thumb. In addition, the median nerve penetrated the humeral head of the pronator teres muscle. Isolated musculocutaneous neuropathy with such a communication may cause unexpected symptoms such as sensory deficit in the palm and muscular weakness of the forearm and the thumb.