If you cut the arm out into small pieces and threaded them together down your arm, it would have like 11 pivot points to wrap around your arm for good mobility. In the pic it looks like a series of jagged rings stacked up your arm, but you probably will get more flexibility if each "ring" was also hinged around your arm in several pieces.
Am I making any sense or??
Maybe a few solid rings in the middle of the bicep, and hinged pieces at the elbow. Just brainstorming...