Aortic valves are heart valves located at the bases of the aorta. Each of them lies in between the left ventricle and the aorta. Together with pulmonary valve, the aortic valves make up the semilunar valves of the heart.
In humans, the aortic valve generally has three cusps or leaflets: the left cusp, the right cusp, and the posterior cusp. In few instances, the aortic valve may have only two. The cusps of the aortic valve regulate the opening and the closure of the valve. When open, the blood from the left ventricle flows into the aorta. When it closes, the blood is prevented from going back to the left ventricle. The valve opens when the pressure in the left ventricle rises during ventricular systole. It closes when the pressure drops rapidly at the end of the ventricular systole.