MODEL RELEASED. Ranch owner cooking food on a woodstove, with the aid of a myoelectric" pros- thetic arm. This artificial right arm worn with a hand, is battery powered. Small electrodes placed on the skin at the site of amputation, sense the electrical activity of the remaining arm muscle. These muscle signals are electronically amplified and are used to move the prosthetic arm as required. It gives the user fine control over the limb, and the ability to use the arm slowly or quickly, with precision and varying strength. Here, it is used to hold the handle of a frying pan. The "myoelectric" arm was developed at the University of Utah, USA. Photograph of Bob Goodman."