One of the foremost problems in rehabilitation today is the prevention of bedsores or decubitus ulcers in spinal cord-injured patients. For those patients who must spend great lengths of time in a wheelchair, the wheelchair cushion is of vital importance in avoiding the high forces on the skin that could cause tissue breakdown. The finite element method was used to analyze a two-dimensional model of the human buttocks. The normal and shear stresses in the flesh were determined for several body types supported by a variety of cushion materials. Results permitted a comparison of external pressure measurements made experimentally with calculated internal stresses. Thus, analysis supplemented clinical observations in evaluating the ability of cushion materials to minimize stresses in the flesh.