The radial collateral artery originates as a branch of the deep brachial artery. Its path travels behind the humerus, which is the only bone of the upper arm. The artery then descends down the lateral aspect of the humerus. This refers to the area of the humerus that is furthest from the body’s midline. It terminates when it divides into two branches. These branches travel toward the front and back of the arm respectively. The artery is situated within the profunda brachii. This is also known as the deep brachial artery. The profunda brachii is a term for a vast vessel that comes out from both the posterior and lateral segments of the brachial artery, right below the lower edge of the teres major muscle. The profunda brachii runs alongside the radial nerve. It then runs within its groove, which is called the radial sulcus. It also provides the deltoid muscles with several branches.