Abstract:During routine dissection of an adult male cadaver in the Department of Anatomy It was found that the right median nerve was formed by three roots, two coming from lateral cord and one from medial cord of brachial plexus.The uppermost or highest root was noted to be at the level of origin of coracobrachialis muscle. The second root was found to be immediately below the first one.These two roots were found to be passing obliquely in front of second and third part of axillary artery and joining individually with the medial root of median nerve and forming median nerve trunk, in front of third part of axillary artery. (Figure No.-1) Further distribution of the anomalous median nerve in the arm, forearm and palm was normal. The arterial pattern in arm was also normal. The left median nerve was also normal. Discussion:The median nerve is normally formed by the union of two roots: lateral root of median nerve coming from the lateral cord (C5, C6, C7) of brachial plexus and medial root of median nerve coming from the medial cord (C8, T1) of brachial plexus. The two roots embrace the third part of the axillary artery, uniting anterior or lateral to it. Some fibres from C7 often leave the lateral root in the lower part of the axilla passing

The coracobrachialis muscle in the arm is morphologically the sole representative of adductor group muscle in the arm, but such function during the process of evolution became insignificant in man. It is more important morphologically than functionally. Variant insertion of the coracobrachialis muscle was found during routine dissection of an adult male cadaver in the Department of Anatomy, College of Medical Sciences, and Bharatpur, Nepal.Normally the coracobrachialis muscle is inserted into the middle of the medial border of the humerus. In the present case an additional slender tendon passed inferiorly, crossing anterior to the median nerve and brachial artery, before attaching to the medial epicondyle of the humerus. Most of the proximal part of the tendon gave rise to an aponeurotic expansion that inserted into the distal medial border of the humerus. The tendinous insertion and aponeurotic expansion may represent a variant of the coracobrachialis longus (Wood's) muscle and the internal brachial ligament or the ligament of Struthers. The ulnar nerve was found to be traversing below the aponeurotic expansion. This type of anomalous insertion of coracobrachialis muscle may lead to compression of median nerve, brachial artery and ulnar nerve.