Abstract: A subcutaneous bone expansion device including a stationary plate and an expansion plate, each affixed to bone portions, and an expansion mechanism to vary relative distance between the stationary plate and the expansion plate. The expansion mechanism may be operated from a location remote from the stationary plate and expansion plate. The device may be located almost entirely subcutaneously, except for portions of the expansion mechanism necessary to effect operation of the device. Those portions of the expansion mechanism necessary to effect operation of the device may exit from within the body under the skin at a location remote from the location of the expanding bone portions. The bone expansion is a gradual process. As the bone portions are separated by small distance, distraction of callus between the bone portions generates new bone to fill the gap between the bone portions.