Fusion between the median and musculocutaneous nerve: A case study.

The musculocutaneous nerve (C5-C7) is a terminal branch of the lateral cord of the brachial plexus and provides motor innervation to the anterior compartment of arm muscles. Both the musculocutaneous and median nerve may show numerous anatomical variations. Keeping in mind possible aberrations in the course of the upper limb nerves may increase the safety and success rate of surgical procedures. The presented report is a detailed anatomical study of the fusion between the median and musculocutaneous nerve, supplemented by intraneural fascicular dissection. In the presented case, the musculocutaneous nerve was not found in its typical location in the axillary cavity and upper arm during the preliminary assessment. However, a careful intraneural fascicular dissection revealed that musculocutaneous nerve was fused with the median nerve and with its lateral root; Those nerves were surrounded by a common epineurium, however they were separable. The muscular branch to the biceps brachii muscle arose from the trunk (fascicular bundle) dissected out from the median nerve and corresponding to the musculocutaneous nerve. Such variation may be of utmost clinical importance, especially during reconstructions of the brachial plexus or its branches.