Craniosynostosis

Craniosynostosis is a condition where an infant has premature fusing of the sutures in his head, leading to ossification. What is interesting is that the ossification is of mesenchyme. The sutures that hold the bones of the head together are made from fibrous tissue. But they have two more important functions: to allow the baby's head to fit through the birth canal, and separation of the bones that make up the skull cap.

Membrane ossification of the cranial bones occurs during the first few weeks of fetal development, the first trimester of pregnancy. The 4 bones that make up the skull cap are the frontal, parietal, and occipital (anterior + squamosal). What determines the fusion of these bones are many factors such as transcription factors, EM molecules, and cytokines. The precise process is not known. A combination of genetic and environmental factors cause craniosynostosis. Below is a table that discusses the types of craniosynostosis and the characteristics associated with them. The table also comes from the reference below.

BUROKAS, LAURA. "Craniosynostosis: Caring For Infants And Their Families." Critical Care Nurse 33.4 (2013): 39-51. Academic Search Premier. Web. 21 Sept. 2014.