Aortic Valve

Three-corner semilunar valve (pocket valve) between left ventricle and aorta. It has three crescent-shaped (therefore semilunar) pockets which close off the ventricle to the aorta. These are

• Valvula semilunaris posterior
• Valvula semilunaris dextra
• Valvula semilunaris sinistra

The three pockets are filled by backflowing blood and pressed towards the heart, causing them to lie against each other and function as a valve. The blood cannot flow back into the heart, whose pressure drops in the Diastole and is then lower than that of the aorta.

https://en.wikipedia.org/wiki/Aortic_valve _([1])