Abstract
The purpose of the elbow lock incorporated in an artificial arm is discussed and the difficulties encountered in the operation of purely mechanical devices are outlined. An electrically driven locking mechanism has been built which is controlled by the electromyogram (e.m.g.) of the surviving muscles in the upper arm. Hybrid technology is ideally suited to the construction of the associated electronic circuitry and to many similar applications now being considered in attempts to improve the performance of upper-limb prostheses.