Other than the anterior and posterior fontanelles, the mastoid fontanelle and the sphenoidal fontanelle are also significant. The closures eventually form the sutures of the neurocranium. The sphenoidal and posterior fontanelles close during the first few months of life. The ossification of the bones of the skull causes the anterior fontanelle to close over by 9 to 18 months.
It lies at the junction between the sagittal suture and lambdoid suture.
These are joined by fibrous sutures, which allow movement that facilitates childbirth and brain growth. An infant's skull consists of five main bones: two frontal bones, two parietal bones, and one occipital bone.