A conventional prosthetic arm allows three motions: open/close the hand, rotate the hand inward/outward, and bend/stretch the elbow. The movements can only be performed one-after-the-other. They have to be laboriously initiated and consciously carried out in what turns out to be quite a strength-sapping procedure that doesn’t even result in precise, fluid movements. Intelligent prosthetic devices by Otto Bock feature major improvements: they can directly implement mental commands, and the joints can also be moved simultaneously. The prosthesis is controlled by the nerves that were originally responsible for moving the arm. Plus, instead of just three joints, seven active joints are available, which expands the user’s potential range of motions.
