Bicuspid aortic valve The presence of an aortic valve with two instead of the normal three cusps (flaps). Bicuspid aortic valvue is a malformation of a commissure (small space between the attachment of each cusp to the aortic wall) and the adjacent parts of the two corresponding cusps forming a raphe (the fused area of the two underdeveloped cusps turning into a malformed commissure between both cusps; the raphe is a fibrous ridge that extends from the commissure to the free edge of the two underdeveloped, conjoint cusps). A normal aortic valve is composed of three aortic-valve cusps, each semilunar in appearance. The leaflets are housed within a small dilatation of the proximal aorta associated with each cusp, called the sinuses of Valsalva or aortic sinuses, and their association with the respective coronary ostia identifies them: left, right, and non-coronary sinuses. Each cusp is attached to the wall of the aorta by the outward edges of its semicircular border, and the attachment point between each leaflet is called a commissure [PMID:24827036]. SNOMEDCT_US:72352009 UMLS:C0149630 HP:0001647 Abnormal aortic valve cusp morphology bicuspid aortic valve biscupidate aortic valve