Abstract: An inflatable cushion for use in a system and method in supporting the knees and legs of a person during surgery included an inflatable bladder that can move from a collapsed state to an expanded state. A bladder port communicates with a source of inflating gas. The system includes the source of pressurized gas and a valve assembly to switchably control the inflation and deflation of the bladder. The bladder may have a removable cover extending around the bladder, and the bladder may have side pleats to assist in expanding with the cover having corresponding accordion folds. The method involves placing a patient on a surgical table, decompressing the patient's spine to a flat back/drop knee position, interposing the bladder between the table and the patient's knees and advancing the knees to a full prone position by inflating the bladder.