Observations on the growth and orientation of the anterior cranial base in the human foetus

Abstract

The orientation and size changes of the anterior cranial base in relation to the position and size changes of the upper and lower jaw, during the second half of prenatal life, were studied in 31 human foetuses, 16 to 27 weeks old. In every half head, landmarks corresponding to the cephalometric points S, N, Ba, A, B, O and Po were defined, using heads of pins secured at the exact location of these landmarks. Lateral standardized radiographs were taken for each half head and 62 radiographs were used for tracing and measurements related to the anterior cranial base and the jaws. The data were statistically analysed and the findings lead to the following conclusions: During the foetal period studied, the orientation of the anterior cranial base is stable; also, the anteroposterior growth of the anterior cranial base depends more on the growth of the anterior part (N–Se) than the posterior part and there seems to be an early predetermination in the total length of the anterior cranial base. Also, the length of the anterior part of the anterior cranial base (N–Se) has a significant correlation with the length of the maxilla.