Terminal Devices and Other Components
A terminal device is the portion of an upper extremity prosthesis that acts as a hand. Terminal devices provide most of the function of the prosthesis and can be disconnected at the wrist to allow the user to switch to a different device.
Terminal devices are operated by either a body-powered prosthesis or an externally powered prosthesis. The passive hand is a device that does not open or close, but does restore a cosmetically pleasing appearance. Other hands open and close by way of the body-powered harness system.
Electric hands are probably the most popular as they allow the user to grasp items and also have a reasonably natural appearance. The most advanced of these incorporates sensors in the fingers and hand so that grip strength can adjust automatically.
People who work with their hands often prefer grippers and hooks. Again, these devices can be either body-powered or externally-powered. Grippers and hooks can lift heavier items, have a variable grasp pattern, and are better for picking up and holding smaller objects like a screwdriver or key. Some models can even be used in wet environments.
There are many adaptive accessories that make it easier to hold everything from steering wheels to golf clubs, pool cues to fishing poles.
Hands, grippers, hooks and adaptive accessories each have advantages and disadvantages. Ideally, upper extremity users will be best served with a quick disconnect wrist unit that allows them to switch between various devices.
Depending on your level of amputation, other components that will be important are wrist units, elbow units and shoulder units. Your UEPP(Upper Extremity Prosthetics Program) prosthetist will guide you in making the right choices that will improve your function and independence.