Fig 12B-2. A, high-level bilateral upper-limb amputees may benefit from the application of externally powered components. Although the pictured amputations are at the humeral neck level, they are the functional equivalent of bilateral shoulder disarticulations. B, the presence of reliable anterior and posterior deltoid myoelectric signals on the right side along with reliable myoelectric signals from the infraspinatus and pectoralis minor muscles on the left allow this man to proportionally control bilateral electric elbows, wrist rotators, and hands. A shoulder shrug is used to control microswitches in the humeral segments to select between wrist and hand control. Elbow locking/unlocking is triggered by abducting the humeral remnants 2 mm and touching additional microswitches. The small square black buttons near the deltopectoral groove can be touched with the cheek to turn either prosthesis on or off, even through clothing. C, a body-powered hook that could be interchanged with the myoelectric hand was also provided on one side. The harnessing was carefully planned so that the prostheses could be readily donned and doffed without assistance. D, the combination of body-powered hook plus myoelectric hand offers a variety of grasp patterns and grip forces.