FEATURES OF THE ANATOMICAL STRUCTURE OF THE THYROID GLAND OF FETUSES IN AGED 14-18 WEEKS

Abstract

The purpose of our study is to describe the macromicroscopic anatomy of the thyroid gland in the intermediate fetal period of human ontogenesis. The study was performed on 30 human fetuses of both sexes and age from 14 to 18 weeks of gestation, from the collection of the Department of Human Anatomy of the Russian Ministry of Health. To describe the macro -microscopic anatomy of the thyroid gland, we used horizontal cuts according to N.I. Pirogov, horizontal histotopograms at the isthmus level, stained with hematoxylin and eosin, according to the van Gieson method. Morphometry was performed using a laboratory stereoscopic microscope MicroOptix MX 1150, MBS-10. Statistical data processing was performed using Microsoft Word, Excel, Statistica 8.0. The thyroid gland of fetuses at the age of 14-18 weeks of development consists of the right and left lobes, the isthmus, and the pyramidal lobe. In 46,7% of observations, the thyroid gland has the form of a butterfly, in 23,4% - the shape of the letter “H”, in 16,7% - a semilunar shape, in 6.6% - a navicular and asymmetric shape. The height of the right lobe of the thyroid gland was 5,80±0,38 mm, width-3,20±0,36 mm, anteroposterior size - 2,86±0,19 mm. The values of similar parameters of the left lobe were 5,68±0,38 mm, 3,34±0,23 mm, and 2,91±0,29 mm, respectively. The distance from the thyroid lobe to the hyoid bone on the right was 4,75±0,70 mm, on the left - 5,01±0,58 mm, with a variable range from 4,00 to 6,00 mm. The upper pole of the right lobe was most often projected to the upper edge of CIII in 46,7% of observations and to the middle edge of CIII in 46,7%. The upper pole of the left lobe in 53,4% of observations was projected to the middle of the CIII. The lower pole of the right lobe was projected in 53,4% of observations on the intervertebral disc between CIV and CV. The lower pole of the left lobe was projected onto the intervertebral disc between CIV and CV in 60% of the observations. The upper edge of the isthmus was projected to the middle of the CIV in 53,4% of observations. The lower edge of the isthmus in 53,4% was projected onto the lower edge of the CIV. The thyroid gland in the fruits of the studied group has a follicular structure, along the periphery of the organ, the follicles are rounded, some of them are filled with colloid. Thus, the study of the macro -microscopic anatomy of the fetal thyroid gland showed that by the beginning of the study period, it has a structure typical of the adult thyroid gland. The fetal thyroid gland is located above the skeletotopic projection of an adult. In fetuses of 14 weeks of development, the thyroid gland has a follicular structure.