In the arm, the brachial artery arises from the axilliary (armpit area) artery via the subclavian (under the clavicle or collar bone) artery and branches into the ulnar (pinkie side) and radial (thumb side) arteries. These two arteries meet at the deep palmar arch in the palm of the hand. Blood is returned from the arm to the heart via the median cubital vein, the basilic vein, and the cephalic vein. As it flows through the bend inside the elbow, the median cubital vein is a common site from which phlebotomists draw blood samples.
The circulatory system carries blood to all parts of the body, and the one-way flow of blood within the body is called circulation. Arteries (carrying oxygen-rich blood) transport blood away from the heart. Veins (carrying oxygen-poor blood) transport blood back to the heart.
Texas Heart Institute www.texasheartinstitute.com/HIC/Anatomy/arm_anat.cfm