Two hundred twenty-one aortic cusps from 96 patients who underwent aortic valve replacement were examined. Of all the cusps that showed any calcific deposits, 87% had calcific deposits in 1 of 2 specific patterns: a coaptation pattern, where calcific deposits occurred along the line of cusp coaptation, and a radial pattern, where calcific deposits occurred as spokes spread inward from the cusp attachment to the center of the cusp. This was true irrespective of the patients' sex or age, the type of disease, and the type of valve or the extent of calcific deposits. These patterns of calcific deposits relate to the area of maximal cusp flexion and, hence, maximal mechanical stress. It is therefore concluded that calcific deposits in aortic valve cusps occur in specific patterns in most cases, and that mechanical stress may be the initiating or accelerating factor in the calcification of these cusps.