ABSTRACT
When biomechanical professionals speak about bones in the context of biomechanics, their must always use the other two components of the moving mechanism—joints and muscles. There are only four bone types—long, short, flat, and irregular. Long bones are characterized by a cylindrical rod with large knobby ends. Short bones are solid, small bones. Flat bones are the sternum, scapulae, ribs, pelvic bones, and patella. Irregular bones are all the bones of the spinal column, including the 24 vertebrae, plus the sacrum and the coccyx. About 60% is made up of minerals such as calcium phosphate and calcium carbonate, which gives bones the rigidity to resist compression. Muscle insertions, whether proximal or distal, are the place where the force is applied to the bone. Muscles attach to bones at some distance from the joint. If a muscle's contraction tends to produce a joint action opposite to some given joint action of another specific muscle, then the muscle has an antagonistic role.
