Metopic sutural closure in the human skull.

The present study reveals the presence in the sutural area of secondary cartilage, assuring the passive growth of the bones and undergoing an endochondral ossification, but without playing a direct role in the synostosis. The chondroid tissue is responsible for the growth of each frontal bone towards the other and constitutes the first bridge of union between the two bones. It is the most important finding in this study, which provides a description of the closure of the metopic suture and of the maintenance of an open sutural space by a process of active resorption. This new knowledge will help to understand better the whole process of suture closure and its pathology

Calcified tissues involved in the ontogenesis of the human cranial vault.

The cranial vault of fifteen human subjects varying in age from 20th week of gestational life to 9th month post-matum were submitted to microradiographic and histological analysis. Different phenomena such as cortical drift, bone cavitation and progressive substitution of different calcified tissues by lamellar bone are illustrated. Moreover, this study reveals in several areas the presence of chondroid tissue; it constitutes the edges of the sutures and is responsible for their growth till the post-natal period. Therefore, it can be supported that the role of chondroid tissue is essential for the harmonious development of the cranial vault