This invention provides a compact self-contained design of a wrist device for an electrically powered prosthesis. The wrist prosthesis, which provides user controlled motion in two directions, flexion/extension and rotation. Through the unique mounting of the one or more actuators or motors, a significant space savings is achieved. The modular terminal device distal mounting platform and prosthesis proximal mounting structure allow for this wrist device to function with many commercially available terminal devices and prosthesis designs. In a more particular embodiment related to a prosthesis the wrist device utilizes a system of gears, which achieves appropriately externally powered motion and is configured to provide wrist flexion as well as rotation. The prosthesis allows user controlled flexion/extension and rotation by providing two actuating motors and a series of gears, which provides externally powered flexion, extension, and rotation in various ranges.