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.
One of the most frequent comments I hear from new clients is, “I can’t do that because my knees are bad.” And my response is always, "Your knees are problematic because you haven’t been doing that move." A majority of the chronic knee pains that my clients experience are caused by imbalances or poor flexibility in the muscles around their knees, like their quadriceps, hamstrings, and calves—they're not caused by injuries that damage the structure of their joints.