A new prosthetic hand

PROSTHETIC LIMBS3D have been around for a long time. The oldest known, a piece of wood carved and painted to replace the lost toe of an Egyptian noblewoman, dates back more than 3,000 years. But prosthetics which behave like the real thing as well as looking like it are still very much a work in progress. And a group at Shanghai Jiao Tong University, in China, have just come up with what looks to be a significant advance—an affordable prosthetic hand that not only responds like a real one to signals from the wearer’s brain, but is also able to signal back to the brain what it is touching and doing.Gu Guoying and his colleagues describe their invention in . Its fingers are made of rigid tubes connected by soft joints. These are similarly connected to a -printed plastic palm. The whole is covered with a flexible elastomer layer to mimic skin and is attached to the user’s residual limb via a customised plastic socket. In contrast to current models, which are electrically powered, Dr Gu’s hand is powered pneumatically by a pump held in a waist bag, with the connecting air lines running under the user’s clothes alongside communication cables. This reduces its weight below 300 grams—half that of some current models, and less, indeed, than the weight of a real hand—though the waist bag adds a further 444 grams.