Skull Sutures and Craniofacial Disorders: Mind the Gap.

The human skull, whose 22 separate bones make up the cranial vault, facial bones and jaw, is arguably the most complex skeletal structure in the body. In addition to protecting the brain, it provides structures necessary for mastication and audition and serves as the underlying scaffold for the face to define our unique identities. Proper development and growth of the skull requires initial incorporation of positional information to cranial neural crest cells (CNCC) and paraxial mesoderm to define the location of each bone followed by the coordination of postnatal cranial growth with the underlying expansion of the brain, a process that is mediated by two specific growth centers, cranial sutures and cranial base synchondroses. This Perspective will provide an overview of general principles governing craniofacial development, growth, and regeneration with emphasis on the unique functions of neural crest cells, cranial sutures, cranial base synchondroses and associated stem cells. In addition, examples will be included of how defects in skull development can explain specific craniofacial disorders as well as future directions for cranial bone regeneration and correction of craniofacial anomalies that are informed by recent discoveries in this field.