Mitral valve Mitral valve The mitral valve (), also known as the bicuspid valve or left atrioventricular valve, is a valve with two flaps in the heart, that lies between the left atrium and the left ventricle. The mitral valve and the tricuspid valve are known collectively as the atrioventricular valves because they lie between the atria and the ventricles of the heart. In normal conditions, blood flows through an open mitral valve during diastole with contraction of the left atrium, and the mitral valve closes during systole with contraction of the left ventricle. The valve opens and closes because of pressure
Mitral valve away from the free margin. This disposition has important effects on systolic stress distribution physiology The mitral annulus is a fibrous ring that is attached to the mitral valve leaflets. Unlike prosthetic valves, it is not continuous. The mitral annulus is saddle shaped and changes in shape throughout the cardiac cycle. The annulus contracts and reduces its surface area during systole to help provide complete closure of the leaflets. Expansion of the annulus can result in leaftlets that do not join soundly together, leading to functional mitral regurgitation. The normal diameter of the mitral annulus is , and the circumference