We developed a prosthesis with 3 powered DOFs to enable use of the new targeted muscle reinnervation control sites. It consisted of: a manual locking shoulder; Boston Digital Arma modified to accept additional electromyographic inputs with a passive friction humeral rotator; a powered wrist rotator (model #10S17),b and a powered hook (Greifer model #8E32b) (fig1A). The 4 targeted muscle reinnervation electromyographic control signal sites allowed the subject to simultaneously operate his terminal device (hook or hand) and elbow in an intuitive manner. He could have operated his wrist rotator simultaneously using shoulder inputs, but preferred to use sequential control of the terminal device and wrist with his hand open and close targeted muscle reinnervation electromyographic control signal sites. This was preferred so that he could avoid dropping objects by disabling the terminal device when switching to wrist. The subject uses this prosthesis on a regular basis at home; he wears this device 3 to 5 days a week for 2 to 8 hours at a time..