The aorta, which is about 1 inch (2.5 centimeters) in diameter, is the largest artery of the body. It receives oxygen-rich blood from the left ventricle and distributes it to all of the body except the lungs (which receive blood from the right ventricle). Just after the aorta leaves the heart, smaller arteries that carry blood to the head and arms branch off. The aorta then arches down, with additional smaller arteries branching off along its route from the left ventricle to the lower abdomen at the top of the hipbone (pelvis). At this point, the aorta divides into the two iliac arteries, which supply blood to the legs.
Disorders of the aorta include bulges (aneurysms) in weak areas of its walls and separation of the layers of its wall (dissection). These disorders can be immediately fatal, but they usually take years to develop. Aneurysms may also develop in other arteries.
Last full review/revision January 2008 by John W. Hallett, Jr., MD