MORPHOGENESIS OF BRANCHIOGENIC GLANDS OF THE NECK IN THE FETAL PERIOD OF ONTOGENESIS

Branchiogenic glands play an important role in the control of calcium and iodine levels and thus have a direct impact on muscle contraction and neurotransmission. Variations in the structure and ectopic location of parathyroid and thyroid glands increase the complexity of thyroid and parathyroid surgery. Aim. To study the variants of structure and anatomical features of the parathyroid and thyroid glands at different stages of fetal development. Materials and methods. To study the anatomical variability of the branchiogenic glands of the neck in the fetal period of ontogenesis, we chose a set of classical methods of morphological research: morphometry, thin dissection under the control of a microscope, and photographic documentation. The material for the study were 48 preparations of human fetal cadavers from the 4th to the 10th month of intrauterine development. Digital parameters of organs and their correlation with neighboring organs and structures were grouped into appropriate age groups and processed by non-parametric methods of variation statistics with calculation of their arithmetic mean, its error and determination of probability of differences by Student's t-test using MS Excel and Biostatistics programs. The study was conducted in accordance with the main provisions of the Law of Ukraine ¹ 1801-XII "Fundamentals of the Legislation of Ukraine on Health Care", GCP (1996-2016), the Declaration of Helsinki of the World Medical Association for the Ethical Principles of Scientific Medical Research Involving Human Subjects (1964-2013), the Convention of the Council of Europe on Human Rights and Biomedicine (04.04.1997), Order of the Ministry of Health of Ukraine No. 690 dated 23.09.2009, and therefore concluded that the proposed study should be recommended for publication. The article is a fragment of the research work of the Department of Surgery № 1 of Bukovinian State Medical University: ‘Development, substantiation and implementation of new approaches to the diagnosis and treatment of some acute surgical diseases, prediction of their course and prevention of complications’, state registration number - 0121U110501: 01.2021-12.2025. Results. At the beginning of the fetal period of human ontogenesis there is an intensive development of the parathyroid glands. Variability of morphology of upper and lower parathyroid glands was found in 15 fetuses of 4-5 months of age. During this period, the following forms were observed: elongated, oval, bean-shaped, crescent-shaped. In the study of 15 fetuses at the age of 6-7 months, the following variations in the shape of the upper and lower parathyroid glands were found: oval, elongated, round, crescent, lenticular, bean-shaped. Topographically, we found the following variations in the location of the upper parathyroid glands: 1) between the upper and middle thirds of the thyroid lobes; 2) at the level of the upper third of the thyroid gland; 3) at the level of the middle third of the thyroid gland; 4) in the parenchyma of the thyroid gland; 5) above the thyroid lobes - 40% (20 cases), 36% (18 cases), 10% (5 cases), 8% (4 cases), 6% (3 cases), respectively. Conclusions. 1. The variants of the structure and topography of the thyroid gland, the upper parathyroid gland and the lower parathyroid gland, which we have identified, can be anatomical conditions for the development of both congenital pathology and variants of normal structure, which can nevertheless cause iatrogenic disorders during surgery. 2. In fetuses of 4-10 months of age, numerous variants of the structure and topography of the upper parathyroid gland and lower parathyroid gland are observed, which differ significantly from their typical structure. 3. The aplasia of the upper pineal gland detected in two human fetuses of 7 months of age is due to the peculiarities of their organogenesis and the formation of syntopia in the embryonic and prenatal periods of prenatal morphogenesis. 4. The obtained data on individual anatomical variability of the pineal glands should be taken into account by endocrinologists and ultrasonographers when performing diagnostic and surgical procedures.