New actions were possible with the 6-DOF prosthesis. The workspace was increased in the 6-DOF arm by the ability to actively raise the shoulder, rotate the upper arm, and flex the wrist. With a conventional prosthesis a user can unlock a nonpowered shoulder, bend forward allowing shoulder flexion through gravity, and then relock the shoulder. This allows use of the prosthesis with the shoulder in a fixed angle from 0° to 90°, making reaching objects above the head difficult. The powered shoulder allowed much faster and easier operation with an operating range from 15° to 185° of flexion. The vertical work space was effectively doubled with the powered shoulder and allowed the subject to reach items above his head.The passive humeral rotator had full ROM, but obviously control was very limited and could only be manipulated by pushing the arm against objects with the arm down and the elbow flexed to approximately 90°. However, the powered humeral rotator allowed dynamic control of a full ROM. It allowed the subject to reduce compensatory movements, such as moving his torso, and to stand in a fixed position. More importantly, it allowed the device to cross the midline for bimanual activities and to reach parts of the right (contralateral) side of his body. The wrist flexion unit allowed the subject to bring his terminal device farther towards his body (an option not present, even passively, with the 3-DOF prosthesis). Compared with a hand lacking wrist flexion and extension, this hand flexed and extended approximately 60° in either direction. This amount of flexion translates to over 11cm in additional workspace in either direction. The wrist flexion and extension unit allowed better prepositioning of the hand, especially with respect to high and low surfaces. For example, this was necessary for picking up a small object off of a high shelf. Note the fully flexed wrist in figure 3A. This pick-up could not be done without this function