aorta

The great artery, or trunk of the arterial system; proceeding from the left ventricle of the heart, and giving origin to all the arteries, except the pulmonary arteries. It first rises, when it is called the ascending aorta; then makes a great curve, when it gives off branches to the head, and upper extremities; then proceeds downwards, called the descending aorta, when it gives off branches to the trunk; and finally divides into the two iliacs, which supply the pelvis and lower extremities.