A STUDY ON THE CRANIOFACIAL GROWTH AND DEVELOPMENT IN KOREAN EMBRYOS AND FETUSES

한국인 태아의 악안면 성장 발육에 관한연구

The objective of this study was to understand the major changes of craniofacial dimensions and spatial growth pattern during the late embryonic and fetal period of human fetures. This study was performed with the selective materials of normal fetuses received from the Registry of Congenital Malformation of Seoul National University Hospital. The specimens consisted of nineteen embryos and sixty-six fetuses. The photomicrographs from mid-segittal sections of embryos were used for angular measurement, and the lateral cephalograms taken with soft X-ray were also measured in liners and angular aspects. All of the anatomical landmarks for the tracing of the photomicrographs and cephalograms were referred to the previous reports on literature. The sequential changes of prenatal craniofacial dimensions and agles were analysed statistically and discussed on the focus about the developmental growth directions of human ore-facial structure arised from heterogeneous origins. The results are as follows, 1) Cranial base angle was almost formed at about 6 weeks old embryos with the average angle of $127.4{\pm}6.33^{\circ}$ (n=3) and it was almost constant onwards. 2) The linear increase rates of anterior cranial base length and anterior facial height exceeded those of the posterior cranial base length and posterior facial height, and the maxilla grows more rapidly on the horizontal dimension than the vertical dmension during the fetal period. 3) The angular relationship between the anterior cranial base and palatal plane decreasedslightly during the fetal period, disclosing $11^{\circ}$ at 12th week gestation and $5^{\circ}$ at 41th weeks gestation. 4) Genial angle was maintained almost constantly at about $130^{\circ}$ during the fetal period from 12 weeks to 41 weeks of gestation.