The aortic valve is one of four valves that control blood flow through the heart, keeping blood flowing in a forward direction. It is located between the left ventricle (pumping chamber) of the heart and the aorta, the large blood vessel that exits the heart. The aortic valve opens as oxygen-rich blood is pumped out of the left ventricle, and closes as the left ventricle fills with blood. This prevents the blood from flowing back into the heart as the left ventricle fills.

Figure 1: Aortic valve in a front view of the heart.

Figure 2: The four valves of the heart and the right and left ventricles, or pumping chambers, of the heart.

Figure 3: A cut-away top view of the four heart valves.