Cranial Suture Biology

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Publisher Summary This chapter focuses on the cranial suture biology. The term “craniosynostosis” was first used in 1830 by Otto to describe the premature fusion of cranial sutures. Since this first identification of craniosynostosis as a distinct clinical entity, several theories have been proposed to explain both the pathogenesis of premature suture fusion and the resultant aberrations in calvarial growth that result in a dysmorphic skull. Recent advances in clinical genetics have resulted in the identification of genetic mutations in the major craniosynostostic syndromes. Despite these insights into the rudimentary disturbances leading to craniosynostosis, the processes by which mutations in these genes trigger premature suture fusion remain largely unknown. Rodents are proving to be extremely valuable in unraveling the cellular and molecular mechanisms of cranial suture morphogenesis and pathology. The cranial sutures include the metopic or interfrontal suture (between the frontal bones), the sagittal suture (between the parietal bones), the coronal suture (between the frontal and parietal bones), and the lambdoid sutures (between the parietal and interparietal bones). The sutures can be thought of as a complex consisting of four principal components: (1) the osteogenic fronts of the approximating bone plates; (2) the suture mesenchyme spanning the osteogenic fronts; (3) the overlying pericranium or cranial periosteum; and (4) the underlying dura mater, a tough, fibrous membrane that constitutes the outer meningeal layer that envelops the brain and forms the inner lining of cranial bones and sutures. The main objective is to obtain a thorough understanding of normal and pathological suture morphogenesis and development. Armed with this knowledge, researchers will be prepared to devise biologically based therapeutic strategies that could be used both in utero or postnatally to prevent craniosynostosis, potentially alleviating any adverse sequelae and avoiding the morbidity of current surgical approaches.