A prosthetic arm apparatus comprising: a plurality of segments (12,14,16,18,20,22,24), wherein each segment of the plurality of segments may be actuated independent of the other segments; wherein at least one segment of the plurality of segments houses electronic controllers for the plurality of segments; and wherein one of the plurality of segments is a hand assembly comprising: a thumb structure; an index finger structure; and a middle, ring and pinky, MRP, structure, characterized in that each of the thumb structure, the index finger structure and the MRP structure are driven independently from each other; wherein at least one segment of the plurality of segments includes a non-backdriving clutch (70,212) comprising: an output hex for driving the segment; an input cage; a clutch race constraining the input cage and the output hex; and a plurality of roller bearings disposed within the clutch race around the periphery of the output hex at an interface between the output hex and the input cage; wherein the non-backdriving clutch is arranged to lock the output hex against the bearing race and the roller bearings to prevent movement with force applied to the output and arranged to disengage the output hex on exertion of input force through the clutch input cage; and wherein the plurality of segments (12,14,16,18,20,22,24) provides a user of the prosthetic arm apparatus with substantially the same movement capabilities as a human arm. a plurality of segments (12,14,16,18,20,22,24), wherein each segment of the plurality of segments may be actuated independent of the other segments; wherein at least one segment of the plurality of segments houses electronic controllers for the plurality of segments; and wherein one of the plurality of segments is a hand assembly comprising: a thumb structure; an index finger structure; and a middle, ring and pinky, MRP, structure, characterized in that each of the thumb structure, the index finger structure and the MRP structure are driven independently from each other; wherein at least one segment of the plurality of segments includes a non-backdriving clutch (70,212) comprising: an output hex for driving the segment; an input cage; a clutch race constraining the input cage and the output hex; and a plurality of roller bearings disposed within the clutch race around the periphery of the output hex at an interface between the output hex and the input cage; wherein the non-backdriving clutch is arranged to lock the output hex against the bearing race and the roller bearings to prevent movement with force applied to the output and arranged to disengage the output hex on exertion of input force through the clutch input cage; and wherein the plurality of segments (12,14,16,18,20,22,24) provides a user of the prosthetic arm apparatus with substantially the same movement capabilities as a human arm. a thumb structure; an index finger structure; and a middle, ring and pinky, MRP, structure, characterized in that each of the thumb structure, the index finger structure and the MRP structure are driven independently from each other; wherein at least one segment of the plurality of segments includes a non-backdriving clutch (70,212) comprising: an output hex for driving the segment; an input cage; a clutch race constraining the input cage and the output hex; and a plurality of roller bearings disposed within the clutch race around the periphery of the output hex at an interface between the output hex and the input cage; wherein the non-backdriving clutch is arranged to lock the output hex against the bearing race and the roller bearings to prevent movement with force applied to the output and arranged to disengage the output hex on exertion of input force through the clutch input cage; and wherein the plurality of segments (12,14,16,18,20,22,24) provides a user of the prosthetic arm apparatus with substantially the same movement capabilities as a human arm. an output hex for driving the segment; an input cage; a clutch race constraining the input cage and the output hex; and a plurality of roller bearings disposed within the clutch race around the periphery of the output hex at an interface between the output hex and the input cage; wherein the non-backdriving clutch is arranged to lock the output hex against the bearing race and the roller bearings to prevent movement with force applied to the output and arranged to disengage the output hex on exertion of input force through the clutch input cage; and wherein the plurality of segments (12,14,16,18,20,22,24) provides a user of the prosthetic arm apparatus with substantially the same movement capabilities as a human arm.