part of part of organ part cardial valve mesoderm-derived structure cusp of cardiac valve cardiac valvule UMLS:C0225923 FMA:7232 semilunar valvule cardiac valve cusp UBERON:0006009 uberon The part of the heart valves that serves to seal the heart valves when closed. There are three cusps for each valve except for the mitral valve, which has only two (hence its alternate name, 'bicuspid valve'). 'Nodules' are located at the tip of the valve, to form a tighter seal[WP]. cardial valve cusp cardiac valvular cusp neural crest-derived structure