During routine dissection, of the right upper limb of a 70 years old donated embalmed male cadaver in the Department of Anatomy, K.J. Somaiya Medical College, Sion, Mumbai, India, we observed a trifurcation of the brachial artery into the radial, ulnar and common interosseous arteries. The brachial artery trifurcated above the cubital fossa in the lower part of the arm. The common interosseous artery was longer in length. The common interosseous artery divided at an unusual site in the cubital fossa into the anterior and posterior interosseous arteries. The radial artery travelled downward along the radial side of the forearm to the wrist. The course of the ulnar artery was normal. There were no associated altered anatomy of the nerves observed in the specimen. The variation was unilateral and the left upper limb was normal. The photographs of the trifurcation of brachial artery into radial, ulnar and common interosseous artery were taken for proper documentation. Conclusion: Topographical anatomy of the normal and abnormal variations of the axillary artery are clinically important for surgeons, orthopaedicians operating on the supracondylar fracture of humerus and radiologists performing angiographic studies on the upper limb. The trifurcation of brachial artery in the lower part of arm may result in excessive haemorrhage during supracondylar fracture of the humerus. A lack of knowledge of such type of variations with different patterns may complicate the surgery and may cause unnecessary bleeding. Therefore both the normal and abnormal anatomy of the region should be well known for accurate diagnostic interpretation and therapeutic intervention. 

Keywords : Brachial Artery; Trifurcation; Radial Artery; Ulnar Artery; Common Interosseous Artery; Surgeons; Orthopaedicians; Supracondylar Fracture; Radiologists; Angiographic Studies.