Circulatory System of Arms
Enough flow of oxygenated blood to—and the removal of deoxygenated blood from—the fingers, hands, arms and shoulders is provided by the cardiovascular system of the upper extremities. Arteries carry oxygen-rich blood away from your heart, and veins carry oxygen-poor blood back to your heart. Large blood vessels, including the brachial artery at the top of the arm and the radial and ulnar arteries in the lower arm provide the upper extremities with oxygenated blood. The brachial artery is the major blood vessel of the (upper) arm. The ulnar artery is the main blood vessel, with oxygenated blood, of the medial aspect of the forearm. The radial artery is the main artery of the lateral aspect of the forearm. These arteries branch into even smaller ones in the hands, including the palmar arteries. Deoxygenated blood is taken away from these sites by corresponding veins (they have the same names as the arteries) in paths parallel to the arteries and carried to the heart and lungs, where oxygen stores are then refilled. Adequate blood flow to tissues helps regulate body temperature, and reduces the risk of frostbite of the fingers in extreme weather conditions, so it is important to health of these extremities.