Unilateral variant motor innervations of flexor compartment of arm (915.10)

Abstract

Variations in the nerves of the upper limb are very important in routine surgeries, where these nerves are more prone for injuries; these variations may also help in interpretation of a nervous compression having unexplained clinical symptoms. The musculocutaneous nerve usually branches out from the lateral cord of brachial plexus. It innervates the coracobrachialis, biceps brachii and brachialis muscles and continues as the lateral cutaneous nerve of forearm without exhibiting any communication with the median nerve or any other nerve. We report a unilateral variation in motor innervations of the right arm in a 72‐year‐old Female cadaver. The musculocutaneous nerve was found to be piercing coracobrachialis muscle, supplying it and later continue as lateral cutaneous nerve of forearm. A muscular branch of the median nerve was supplying the short and long head of biceps muscle. In the middle of arm, the median nerve was found to be giving a separate branch, which supplied the brachialis muscle and continued in the cubital fossa with normal relation to biceps tendon and brachial artery. There was no variation seen in distribution of median nerve in the flexor compartment of forearm and hand. Knowledge of such anatomical variation is of interest to the anatomist and surgeons.