Out On A Limb
In Star Wars, Luke Skywalker loses his hand in a light saber duel with Darth Vader, he's implanted with a cybernetic hand that works just as well as the original. Soon, something like that may actually be possible.
These days most real artificial arms are still pretty crude. They're strapped on, and controlled by electrodes on the skin. They detect electrical activity in the muscles of an amputee's stump. Using those signals, the amputee can command an artificial hand to do simple things like open and close, but the skin signal doesn't allow precise or reliable control.
In 2014, biomedical researchers reported a major breakthrough. They anchored an artificial arm directly to the bone of an amputee's stump with a titanium screw. This gave them a stable base for implanting electrodes permanently under the skin, in direct contact with muscles and nerves, which allowed for dramatic improvements. The system provided near perfect control of a robotic elbow, wrist rotator, and a hand that could open and close.
The researchers stimulated a sensory nerve and produced touch sensations that seemed to the amputee to come from his robotic hand. Current technology doesn't yet allow full independent control of robotic fingers. But now we have created a real cyborg; a directly coupled human machine system, and there's lots of potential for further improvements.
"Mind Controlled Prosthetic Arms That Work In Daily Life Are Now A Reality" (Science Daily)
"Prosthesis Recreates Sensation Of Touch" (The Scientist)
"Seven Real Life Human Cyborgs" (Mother Nature Network)
"The Cyborg In Us All" (The New York Times Magazine)
"The Future Of The Human" (BBC)