A disposable gel pad for cushioning the plate of an operating table's patient support apparatus is a block of gel with one face of the block adapted to locate the pad on the plate. Usually the pad will be enclosed in a film envelope. A pocket in the envelope allows the pad to engage the plate. Stick on patches which provide a pocket and sacroiliac pads axe variants. Sacroiliac pads can be cast with a soft gel front for patient contact joined to a hard gel rear for screw or bayonet fixing to the patient support apparatus.