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]. [ http://en.wikipedia.org/wiki/Cusps_of_heart_valves ]
Synonyms: cardiac valvular cusp cardial valve cusp cardiac valvule semilunar valvule cardiac valve cusp