Skeletal framework of the head. With the exception of the lower jaw, its bones meet in immovable joints (sutures) to form a unit that encloses and protects the brain and sense organs and gives shape to the face. The cranium, the upper part enclosing the brain, comprising the frontal, parietal, occipital, temporal, sphenoid, and ethmoid bones, is globular and relatively large compared to the facial portion. Its base has an opening through which the spinal cord connects to the brain. The skull sits on the top vertebra (atlas), which permits back-and-forth motion. For side-to-side motion, the atlas turns on the next vertebra (axis). See alsocraniosynostosis, fontanel.