Cranial bones are the eight bones that form the protective structure of the skull, encasing the brain. These bones include the frontal, parietal, temporal, occipital, sphenoid, and ethmoid bones. Together, they provide support and protection for the brain, as well as attachment points for muscles that control facial expressions and head movement. The cranial bones are connected by joints called sutures, which allow for slight movement during growth and development. At birth, some of these bones are not fully fused, allowing for the flexibility needed during childbirth. As a person ages, the cranial bones become more rigid and firmly joined.