Mitral valve: A valve in the heart that is situated between the left atrium and the left ventricle. The mitral valve permits blood to flow from the left atrium into the left ventricle, but not in the reverse direction. The mitral valve has two flaps (cusps). It is so named because it looks like a bishop's miter (headdress). Also known as bicuspid valve.
Quick GuideHeart Disease: Causes of a Heart Attack
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Last Editorial Review: 5/13/2016