A Unique Triad of Muscular, Vascular and Nervous Variations in Upper Limb AD01-AD03
Dr. Dharmaraj Wamanrao Tamgire,
Department of Anatomy, Ground Floor, JIPMER Academic Center, JIPMER, Gorimedu-605006, Pondicherry, India.
Multiple muscular and neurovascular anomalies in upper limb are reported continuously in medical literature because of their clinical significance. A unique case of the triad of variations was encountered during routine dissection activity. The variations observed were: 1) Accessory third head of biceps brachii; 2) High division of Brachial Artery; 3) Communication between Musculocutaneous Nerve and Median Nerve. Taken independently these variations are common but it is rare in a single cadaver. These abnormalities were found unilaterally on the right arm of the cadaver. The third head of biceps brachii was seen to be originating from the medial border and adjacent area on the anteromedial surface of the humerus at the level of insertion of coracobrachialis fusing with main muscle belly just before it forms the tendon. Additional head of biceps brachii was supplied by a branch from the Median Nerve. This branch after supplying the additional head of biceps was seen to join the Musculocutaneous Nerve. Further, a higher bifurcation of brachial artery was observed at the level of insertion of coracobrachialis. The medial division was traced distally as radial artery and the lateral division was traced as ulnar artery. The knowledge of these variations is of immense importance to correlate abnormal displacement of fractured bone segments, avoiding fatal injuries to vital structures, transradial angiography and diagnostic clinical neurophysiology.