Structure of the skeleton

The bones of the skeleton can be divided into two different and distinct categories:

1. The axial skeleton: this includes the cranium (skull), the vertebral column (spine) and the rib cage. It forms the basic structure by which the rest of the skeleton is supported.
2. The appendicular skeleton: this includes all the appendages (i.e., the limbs) and the girdles that join them onto the axial skeleton.