The skeleton is a supportive and protective structure in humans and other animals, against which the force of muscles acts. A normal adult human skeleton consists of 206 named bones (or 213 if each of the nine fused vertebrae of the sacrum and coccyx are counted as independent bones). The individual bones of the skeleton are connected by three types of joints, which differ in the type and amount of movement they allow.
The human skeleton is divided functionally into an axial skeleton that supports the main body axis and an appendicular skeleton that supports the arms and legs.