The formation of heart-proportion in fetal ontogenesis.

In the paper, the formation of basic heart proportions in the period from the 19th to 43rd week of intrauterine development was investigated. The material consisted of 1505 fetuses (930 male and 575 female). Length, width and thickness of the heart were measured to 0.1 mm on unpreserved fetus material within 24 hours after stillbirth or death, in the natural position of the organ. The material was divided into groups representing seven developmental periods, from the 5th to the 10th lunar month. Individuals from the 41st-43rd week were recognized as carried beyond term and included in the age category above the 10th month (< 10). Formation of heart proportions was investigated on the basis of a statistical analysis of the results, with both sexes considered separately. Evaluation of the research results confirmed previous results indicating a slightly different shape of the heart in the fetal period. In addition, the results show the changes that occur in heart proportions during the period of intrauterine development. A comparison of these proportions with analogous indices in adult individuals makes it possible to predict further developmental changes in the postnatal period. In comparison to the conical heart found in a grown-up individual, the fetal heart is more spherical. At the beginning of the fetal period, the length dimension of the heart is greater than its width. Beginning with the 9th month of development, a relatively slower elongation of the heart occurs in favour of a more rapid increase in its width dimension.(ABSTRACT TRUNCATED AT 250 WORDS)