Craniosynostosis consists of premature fusion of 1 or more cranial sutures, often resulting in an abnormal head shape. It may result from a primary defect of ossification (primary craniosynostosis) or, more commonly, from a failure of brain growth (secondary craniosynostosis).
Primary craniosynostosis - One or more sutures fuse prematurely, skull growth can be restricted perpendicular to the suture. If multiple sutures fuse while the brain is still increasing in size, intracranial pressure can increase.
* Scaphocephaly - Early fusion of the sagittal suture
* Anterior plagiocephaly - Early fusion of 1 coronal suture
* Brachycephaly - Early bilateral coronal suture fusion
* Posterior plagiocephaly - Early closure of 1 lambdoid suture
* Trigonocephaly - Early fusion of the metopic suture
Secondary craniosynostosis - More frequent than the primary type, secondary craniosynostosis can result from early fusion of sutures due to primary failure of brain growth. Since brain growth drives the bony plates apart at the sutures, a primary lack of brain growth allows premature fusion of all the sutures.Typically, failure of brain growth results in microcephaly.Intrauterine space constraints may play a role in the premature fusion of sutures in the fetal skull.