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Either of two valves, one located at the opening of the aorta and the other at the opening of the pulmonary artery, each consisting of three crescent-shaped cusps and serving to prevent blood from flowing back into the ventricles.
(Anatomy) anatomy either of two crescent-shaped valves, one in the aorta and one in the pulmonary artery, that prevent regurgitation of blood into the heart
either of two heart valves situated at the ventricular openings to the aorta and the pulmonary artery, each containing three crescent-shaped flaps that prevent the reverse flow of blood.
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|Noun||1.||semilunar valve - a heart valve with cusps shaped like half-moons; prevents blood from flowing back into the heart|
aortic valve - a semilunar valve between the left ventricle and the aorta; prevents blood from flowing from the aorta back into the heart
pulmonary valve - a semilunar valve between the right ventricle and the pulmonary artery; prevents blood from flowing from the artery back into the heart