[Dynamics of the cranial base angle changes during the second trimester of the normal intrauterine growth and development].

The aim of this study was to investigate dynamics of the cranial base angle changing during the second trimester of the normal intrauterine growth and development. The material consisted of 35 fetuses, both sexes, derived from artificial abortions of the uncomplicated pregnancies, gestational ages from the 14th to the 23rd week. Measurements of the cranial base angle were assessed from tracings of lateral cephalometric radiographs. It was found that cranial base angle decreased with the age for about 2.25 degrees per week; from 160 degrees in the 14th week to 140 degrees in the 23rd week. However, significant individual variations of the cranial base angle changes also existed. Thus, among the 99% of fetuses investigated, angle of the cranial base decreased from about 2.00 degrees to 2.50 degrees per week.