MORPHOLOGY OF ULNAR NERVE IN AXILLA & ARM & ITS VARIATIONS

The ulnar nerve arises from the medial cord (C8, T1); medial cord also receives fibres from the ventral ramus of C7. Lesions of the ulnar nerve occur behind the medial epicondyle & in the cubital tunnel. When muscles are affected due to ulnar nerve dysfunction, there is ulnar neuropathy at the shoulder, arm & elbow. The study was done on 50 embalmed human cadavers (25 right & 25 left) of both sexes of South Indian adult population obtained from the Department of Anatomy, Bangalore Medical College and Research Institute, Bangalore. Variations in the ulnar nerve in its presence, origin, relations, distribution & communications were observed. Ulnar nerve was present in all 50 upper limb specimens (100%). Ulnar nerve originated from the medial cord of the brachial plexus in 49 cases (98%). In 1 case (2%), the ulnar nerve received C7 fibers from lateral cord i.e. the lateral root of the median nerve and then later fused with the median root of the median nerve. In 49 specimens (98%) ulnar nerve took origin from the tip of the acromion processes. In 1 case (2%) it took origin from distal to the tip of the acromion process. 49 specimens (98%) showed the normal course, i.e. medial to axillary & brachial artery. 1 case (2%) showed ulnar nerve present anterior to the third part of the axillary artery and brachial artery. In the midarm it passed medially as a normal course, then runs distally through the cubital tunnel. The awareness of these variations along the normal pattern are helpful for the interventional radiologists, orthopaedicians and neurologists in preventing untoward iatrogenic injury to the ulnar nerve during radiological procedures or operating on fractured patients or diagnostic therapy.