The formation of the proportions of the liver, spleen and kidneys in the fetal ontogenesis.

The paper discusses the formation of basic proportions of the liver, spleen and kidneys between the 21st and 43rd week of pregnancy. 433 fetuses and 941 newborns, selected from 632 fetuses and 1276 newborns, were tested. Measurements of the length, width and thickness of these organs have been taken to the accuracy of 0.1 mm on unpreserved fetuses and newborns within 24 hours after still births or deaths. As the organs under study are parenchymatous, the measurements were taken in their natural position inside the body cavity. The material has been divided into six developmental phases, i.e. from the 6th till the 10th lunar month. Individuals born in the 41st-43rd week were considered to be prolonged and included in the age category older than the 10th month (less than 10). The formation of the proportions of the organs in question has been considered from the viewpoint of a statistical analysis separately for the fetuses and newborns. The analysis of the results confirmed descriptive data available to date about a slightly different shape of these organs during the fetal period and showed the direction of changes occurring in the basic proportions of the organs. Following the comparison of these proportions with appropriate indices in adults, it is possible to predict a further direction of changes in the postnatal period. During the fetal period the organs under study take the shape of the ellipsis since the width-thickness dimensions dominate over the length dimensions. In the postnatal period the organs become slimmer. Significant differences in the size and proportions of the organs under study between the fetuses and newborns have been found in the fetal period.