What is a body-powered prosthesis?

• A. A device that uses a cable system operated by shoulder movement to actuate a hook, hand, or elbow
• B. A device powered by brain signals
• C. A device controlled by voice input
• D. A device using damped hydraulics

Answer: (A)

Body-powered prostheses rely on the wearer’s own movement to operate the device. A harness worn around the shoulder pulls on a cable that runs through the prosthesis to actuate its parts. When the user moves the shoulder or upper body, the cable tension opens or closes the terminal device (like a hook or hand) or moves the elbow, all without any external power source. This makes the system simple, robust, and battery-free, with the energy coming directly from the user.

This contrasts with devices powered by brain signals (which require sensors and motors), voice-controlled systems, or hydraulics, none of which rely on a cable-driven mechanism tied to shoulder movement. The main advantage here is straightforward, reliable control through the user’s own motion, though it does require sufficient upper-body strength and coordinated control to operate smoothly.