In humans, the adult skull is normally made up of 28 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, rigid articulations permitting very little movement.
At birth, the human skull is made up of 45 separate bony elements. As growth occurs, many of these bony elements gradually fuse together into solid bone (for example, the frontal bones).
Craniosynostosis is a medical condition in which the sutures in the skull of an infant close too early, causing problems with normal brain and skull growth. It can result in craniostenosis, which is the skull deformity caused by the premature closure of the cranial sutures. Also intracranial pressure can be increased.