Aortic orifice (anatomy)

The aortic orifice is the aperture produced in the aortic valve when their is blood flow across it. It lies towards the most superior and right side of the left ventricle, just superior to the aortic vestibule.

The size of the fully open orifice is around 2-3 cm. Its size varies significantly with the stages of the cardiac cycle. This is because:

• of valve closure by co-aptation of the valve leaflets during ventricular diastole
• the wall of the sinus above the valve is very elastic in nature. Hence, the systolic wave of pressure can dilate this region. With dilation, the commissures of the valve move away from each other, so placing the valve leaflets under tension. Consequently, when fully open the leaflets are taut and the orifice looks triangular in cross-section.