"The skeleton is the internal framework of the body and is made up of bones and cartilage.  [...]  Bones provide support (when they are locked in position by the muscles and ligaments) and protection (the skull, rib cage and pelvis protect their contents).  They produce motion, acting as levers when pulled by the muscles."—from Eliot Goldfinger in Human Anatomy for Artists: The Elements of Form, Oxford University Press, 1991, p.3