Research in animal models has led to the idea that the dura mater plays an important role in determining closure or patency of the suture. In contrast to the dura mater it appears that the periosteum is not essential in causing closure or patency. Instead of describing the abnormalities in structure and form, research focuses nowadays at decoding the molecular interactions that underlie them. Based on data from quantitative real-time PCR on samples of suture junctions during development, cranial suture fusion in mammals is a tightly orchestrated expression of genes in specific temporal order, leading to endochondral ossification. Despite the progress that has been made, many things are still not understood about the suture biology and the exact causative pathways remain yet to be completely understood.Multiple potential causes of premature suture closure have been identified, such as the several genetic mutations that are associated with syndromic craniosynostosis. The cause of nonsyndromic craniosynostosis however, is still greatly unknown. Most likely, a role is played by biomechanical factors, as well as environmental, hormonal and genetical factors.New insights have given fuel to a debate whether there might be an intrinsic factor causing the premature fusion of the sutures. Brain structures of children with craniosynostosis were evaluated using magnetic resonance imaging. Differences were seen compared with the brain structures of normal children. The question now is whether these differences are caused by the craniosynostosis, or are the cause of craniosynostosis. Biomechanical factors
Biomechanical factors include fetal head constraint during pregnancy. It has been found by Jacob et al.
Physical examination
Fundoscopy should always be performed in children with craniosynostosis. It is used to find papilledema which is sometimes the only symptom of elevated intracranial pressure shown in these children.Other parts of the physical examination include the measurement of the head circumference, the assessment of the skull deformity and the search for deformities affecting other parts of the body. The head circumference and the growth curve of the head provide important clues into making a differentiation between craniosynostosis, primary microcephaly and hydrocephalus. This differentiation has an important influence on the further treatment of the child.In a recent article Cunningham et al. described several steps in which a pediatrician should observe the patient to assess skull deformity:

The first is looking with a birds eye view at the patient while the patient preferably faces the parent while sitting on the parents lap. The goal is to assess the shape of the forehead, the skull length, the width of the skull, position of the ears and the symmetry of the frontal bones and [occiput]. The second is looking at the patient from behind while preferably the child is in the same position as described above. It is important to look at the skull base (to determine whether it is level or not), the position of the ears and to the mastoid (to spot the possible presence of a bulge). The third point of view is the frontal view.