The purpose of this research study is to test the ability to control six separate motors in an externally powered artificial arm (hand, wrist flexion, wrist rotation, elbow, upper limb rotation and shoulder).  We will use electric signals from the muscles in the subject’s chest and buttons on the prosthesis to control the artificial arm.

• Male between the ages of 55-65
• Shoulder disarticulation amputee who has undergone nerve muscle grafts of the pectoralis major and minor to increase the control sites available for prostheses