NORMAL PRENATAL DEVELOPMENT OF THE HUMAN PARIETAL BONE AND INTERPARIETAL SUTURE

This study describes the prenatal human parietal bone development and interparietal suture morphology under normal conditions. The human fet al material consisted of 15 normal specimens, derived from spontaneous and therapeutically induced abortions. The study was based upon a rad iographic analysis of the calvariae. Special attention was paid to the parietal tuber area, the interparietal (sagittal) suture and the fron tal-parietal bone edge, The osseous morphology of these regions showed a well-defined primary ossification center at the tuber region from w here bone trabeculae of uniform size and radiopacity radiated, The uni form trabeculae radiate at nearly right angles to the long axis of the sagittal suture. The bony trabeculae radiate uniformly towards the an terior fontanelle where at the peripheral border of the parietal bone radiopaque, transverse ossification corpora were observed, In the smal l fetuses, these corpora were located anterior to the trabeculae and i n the larger fetuses close to the trabeculae. Insight into the morphol ogical pattern in normal suture formation is essential for the further description of pathological suture morphology and for under standing normal and pathological suture development.