The Biology of the Sutures of the Skull

The sutures of the skull are fibrous joints which accommodate for skull growth throughout development. Complex and coordinated cellular processes regulate their fusion over time. Craniosynostosis results from the premature fusion of cranial sutures, and is a debilitating developmental defect associated with significant morbidities. The objective of suture biology, broadly, is to understand normal and pathological development and morphogenesis. Critical aspects of suture biology include characterization of relevant cell populations and their interactions in suture tissue, emphasized in this chapter. In particular, we place emphasis on the suture mesenchymal stem cell (SMSC) population and recent studies which characterize the role of skeletal stem cells in maintaining a patent suture. Additionally, we discuss interactions between the suture mesenchyme and surrounding pericranium and dura mater. Sutures of the face are similar to sutures of the skull in many ways, functionally, and premature fusion of facial sutures often coincides in diseases involving premature fusion of cranial sutures. However significantly less is known about the stem cell behavior of facial sutures.