The fibrous sutures specifically allow the deformation of the skull during birth and absorb mechanical forces during childhood They also allow the necessary expansion during brain growth.In the very first years of life the sutures serve as the most important centers of growth in the skull. The growth of the brain and the patency of the sutures depend on each other. Brain growth pushes the two sides of the patent sutures away from each other, thereby enabling growth of the neurocranium. This means that the neurocranium can only grow if the sutures remain open. The neurocranium will not grow when the forces induced by brain growth are not there. This will occur for example when the intracranial pressure drops; the sutures do not experience stretching anymore causing them to fuse. Diagnosis
The evaluation of a child suspected to have craniosynostosis is preferentially performed in a craniofacial center. The three main elements of analysis include medical history, physical examination and radiographic analysis.Medical history should in any case include questions about risk factors during pregnancy, the familial rate and the presence of symptoms of elevated intracranial pressure (ICP). Elevated ICP
Symptoms of increased intracranial pressure – such as headache and vomiting – should be questioned after. An elevation of ICP can be present in 4 to 20% of the children where only a single suture is affected. The incidence of ICP in children with more than one suture involved can be as high as 62%. However, even though the children are affected, symptoms are not always present.
observed a FGFR3 mutation in as many as 31% of the cases with nonsyndromic coronal synostosis, thus showing that FGFR abnormalities play an important role in nonsyndromic craniosynostosis.In terms of syndromic craniosynostosis not only do FGFR3 and TWIST genes feature, but also FGFR1 and in particular FGFR2, which has been reported in 90% of the syndromic craniosynostoses such as Apert, Crouzon, Peiffer and Jackson–Weiss. The mutations can be divided into mutations that lead to gain of function (in FGFR genes) and mutations that lead to loss of function (in TWIST genes). Craniosynostosis is therefore likely the result of a disturbance in the fine balance that regulates the multiplication and maturation of the precursor bone cells in the cranial sutures.The familial rate, which is different for nonsyndromic and syndromic cases, provides an important clue. In the nonsyndromic cases, a positive family history is found in 2% of the cases with sagittal suture closure and in 6% to 11%  of the cases with coronal suture closure. Cranial sutures
The mesenchyme above the meninges undergoes intramembranous ossification forming the neurocranium. The neurocranium consists of several bones, which are united and at the same time separated by fibrous sutures. This allows movement of the separate bones in relation to one another; the infant skull is still malleable.