A powered artificial substitute for a missing hand that may be attached to a natural arm or used as part of an upper-limb external prosthetic system, and is designed to replace the appearance and some of the function of the hand. The device moves as the result of a motor(s) that may be integral or proximally mounted with a mechanical link. The control of movement is achieved through amplified muscle action potentials from voluntary contracting muscle in the residual limb/trunk, transmitted via surface electrodes in the device that make contact with the skin, which turn on the motor to provide a function.