An unusual case of additional branches of median nerve innervating the corachobrachialis muscle and its clinical implications

The flexor compartment muscles of the arm comprising of biceps brachii, brachialis and the coracobrachialis are innervated by the musculocutaneous nerve arising from the lateral cord of the brachial plexus. In the present study, we report a case of anomalous innervation of the corachobrachialis muscle on the left side of a 45-year-old male cadaver. The musculocutaneous nerve originated from the lateral cord, as usual and pierced the corachobrachialis muscle. The median nerve was formed by a contribution from both lateral and medial roots, both of which took origin from the lateral and medial cords, respectively. In addition to the usual musculocutaneous nerve which pierced the corachobrachialis muscle and innervated it, two more anomalous branches from the median nerve were observed to innervate the corachobrachialis. The anatomical knowledge of the variations of the innervations of the corachobrachialis muscle may be important not only for surgeons performing coracoid transfer but also for clinicians diagnosing nerve lesions.