Definition, Pathogenesis, and Pathology

This chapter defines craniosynostosis in the text as: “the premature fusing of one or more cranial sutures, with changes in cranial shape and/or dimensions”. The abnormal aspect of craniosynostosis is in the prematurity of the ossification and in the subsequent morphodimensional cranial deformity. The chapter briefly reviews the embryology and growth of the normal skull. It distinguishes, from a pathogenetic point of view, two types of craniosynostosis: Type I craniosynostosis and Type II craniosynostosis. Most of the early reports on craniosynostosis concern damage of the optic nerve and stress the condition as a cause of blindness, when recognized or treated late. Strabismus is also common, more often divergent than convergent. Its actual incidence, however, varies significantly, according to the different types of craniosynostosis. According to several studies dealing with craniosynostosis, chronically increased intracranial pressure may result from the disproportion between skull and brain.