an inflatable knee bolster for a vehicle occupant is mounted in opposing relation to the knees of a vehicle occupant . the bolster is an expansible chamber of multipiece construction having a face portion and a separate three dimensional expansible body portion . the face portion and body portion are joined about their peripheries to define and substantially enclose the chamber . the expansible body portion is formed from injection molded polymeric material and has one or more integrally molded at least partially collapsible pleated profile elements disposed along the sides and across the top of the body portion in raised and lowered profile with respect to the face portion . deformable mounting brackets extend outwardly from the body portion for attachment to the vehicle . the materials forming the face and body portions are of either similar or dissimilar chemical and physical character . actuation of an inflator in fluid communication with the bolster pressurizes the expansible body causing at least a portion of the pleated profile elements to collapsibly deform such that the volume of the enclosed chamber is expanded and the face portion is thrust outwardly to an extended position .