A unilateral variation in the origin and distribution of the arterial pattern of the human upper extremity on the right side is reported on. Apart from its usual branches, the third part of the right axillary artery gave origin to a common branch, the profunda brachii artery and the superior ulnar collateral artery. The right brachial artery, at a point 5.0 cm distal to its origin, bifurcated into the radial and ulnar arteries; their origin was in a position opposite the usual location. The radial artery continued on the medial side of the arm for 2.5 cm and crossed the ulnar artery anteriorly to gain a lateral position in the arm. The inferior ulnar collateral artery arose not from the brachial artery, but from the ulnar artery. A muscle variation was also observed in the right hand, which is compatible with the notion variations within one system of a limb will frequently be accompanied by variations in other systems of the same limb.