fig3

Figure 3. The closed aortic valve is viewed from above (A), having transected the intrapericardial aorta at the level of the sinutubular junction, and from the ventricular aspect (B). The closed valve has three zones of apposition, which extend from the valvar centroid (circle) to the circumference of the valvar orifice (double-headed arrowed lines). The circumferential points are conventionally described as the commissures; Panel B shows the similarity between the closed surfaces of the leaflets, which mark the hemodynamic ventriculo-arterial junction, and the surfaces of the molar and premolar teeth. The open arrows show the extensions of the cavity of the left ventricle to the level of the commissures. There is a shorter extension at the valvar centroid when the valve is closed.