The cranium consists of three main sections including the base of the cranium (occipital bone), the face (frontal bone), and the top (parietal bones) and sides (temporal bone) of the head. Most of the bones of the cranium are permanently set into place prior to birth. However, the temporal and parietal bones are separated by sutures, which remain open, allowing the head to slightly change in shape during childbirth. The cranial sutures eventually close within the first couple of years following birth, after the brain has finished growing.