DEVELOPMENT OF THE BASILAR PART OF THE OCCIPITAL BONE IN NORMAL HUMANFETUSES

The present study aims to investigate the normal maturity and growth o f the basilar part of the occipital bone evaluated radiographically an d histochemically during the first half of prenatal life. The material consisted of cranial bases from 49 normal human fetuses and, in addit ion, three separate occipital bones deviscerated from normal fetuses. The normal development of the basilar part of the occipital bone was d ivided into five maturity stages (OB-I to OB-V). Microscopic investiga tion confirmed the macroscopic findings described. For each stage the ventro-dorsal dimension of the occipital bone component was measured ( LEN). The stages (OB-I to OB-V) were related to gestational age (AGE), crown-rump length (CRL), LEN, and to the length of the humeral bone ( HL). Close accordance was registered between OB stages and length valu es of the basilar part of the occipital bone, LEN, and length of the h umeral bone, HL. A highly significant positive correlation was found b etween LEN and the parameters AGE, CRL, and HL values (P < 0.001). Sta ndards for normal development of the basilar part of the occipital bon e are considered important for evaluation of die pathological prenatal development of the cranial base.