The axillary artery is the origin of all the arteries of the arm. It changes its name for brachial artery after it has crossed the armpit into the upper arm, running behind the teres mayor muscle. The brachial artery goes down along the inner side of the humerus bone to divide into two branches slightly beyond the cubital fossa (the point where the upper and lower arms bend): the radial and ulnar arteries, which run down along the radius and ulna respectively; these two terminal branches of the brachial artery enter the hand to anastomose to form the deep palmar arch and the superficial palmar arch.
As it runs along the upper arm, the brachial artery gives off the deep brachial, superficial ulnar collateral, and inferior ulnar collateral branches. In the lower arm, the interosseous and volar interosseous branches arise from the ulnar artery, while the radial recurrent and carpal branches originate from the radial artery.