Some aspects of the communicating branch between the musculocutaneous and median nerves in man.

Fascicular arrangement of the human brachial plexus is examined on 2 common cases and 3 peculiar cases in which a communicating branch was observed between the median and the musculocutaneous nerve. The musculocutaneous nerve consitss of spinal nerves from C.5, 6 and 7. The branch to the coracobrachialis receives its fibers from C.7 before it leaves the musculocutaneous nerve in 3 cases and after it leaves the musculocutaneous nerve in one case. In one case, C.7 does not send a branch to the coracobrachialis. The median nerve arises by two roots, one from the lateral cord, and the other from the medial cord of the brachial plexus. In a case in which a communicating branch was observed from the median nerve to the musculocutaneous, the fibers from C.7 join to the median nerve via the medial cord. Thus the median nerve involved all elements of the spinal nerve from C.5 to T.1. The elements of the median and the musculocutaneous nerves, therefore, are not affected by appearance of the communicating branch. The communicating branch between the median and the musculocutaneous nerves, consists of the fibers arose from C.5 and C.6, in all examined cases.