The aorta (/eɪˈɔrtə/) is the main artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries).The aorta distributes oxygenated blood to all parts of the body through the systemic circulation.ne way of classifying a part of the aorta is by anatomical compartment, where the thoracic aorta (or thoracic portion of the aorta) runs from the heart to the diaphragm. The aorta then continues downward as the abdominal aorta (or abdominal portion of the aorta) diaphragm to the aortic bifurcation.