The superior ulnar collateral artery refers to a thin artery in the arm. It is also known as the inferior profunda artery. It is located near the middle area in the arm. The artery runs alongside the arteria profunda brachii, which supplies blood to the deltoid muscle. It is sometimes viewed as part of the arteria profunda brachial or as connected to the brachial artery. The superior ulnar collateral artery starts at the triceps brachii on the upper backside of the arm. It ends at the flexor capri ulnaris muscle. This muscle allows the hand to flex. The flexor capri ulnaris muscle is found on the far side of the forearm.