Arteries carry blood from the heart to all areas of the body and, when healthy, have a smooth lining that promotes blood flow and helps to prevent blood clots. Peripheral arterial disease (PAD) is a condition in which fatty deposits (called plaque) build up along the walls of the arteries that carry blood to the arms and legs. This is also known as atherosclerosis or hardening of the arteries. The arteries slowly narrow and may even become blocked, affecting blood circulation, especially in the legs and feet. The February 1, 2006, issue of JAMA includes 2 articles about PAD. This Patient Page is based on one previously published in the September 19, 2001, issue of JAMA.