The purpose of the study was to investigate the features of embryotography of the pharynx and adjacent structures in the prefetus 7–9 weeks of human prenatal development. Material and methods. The study was conducted on 11 human prefetuses of 7–9 weeks (prefetus 17.8–40.0 mm PCL) in compliance with the basic bioethical provisions of the Council of Europe Convention on Human Rights and Biomedicine (04.04.1997), Declaration of the World Medical Association on the Ethical Principles of Conducting Scientific Medical Research with Human Participation (1964–2008), as well as the Order of the Ministry of Health of Ukraine N 690 (September 23, 2009). In our study we used methods of making histological and topographic–anatomical sections, graphic and plastic reconstruction, microscopy and morphometry. Results and discussion. On the basis of the conducted morphological methods, the topographic–anatomical features of the pharynx in the human prefetus were studied and sequentially analyzed. The formation of the embryo topography of the pharynx is closely related to the morphogenesis of the adjacent organs: nasal and oral cavities, palate, larynx and esophagus. The funnel–like recess, which appears on the dorsal wall in the caudal part of the pharynx, becomes more pronounced from the end of the germinal period of development, the distance between its edges in the sagittal section is 30.4±1.3 mcm. The funnel cavity corresponds to the lower border of the pharynx, which corresponds to the place of formation of narrowing of the pharynx at the transition into the esophagus. At the end of the 7th week of prenatal development (prefetus 18,2–20,0 mm PCL), the tab of the epiglottis is clearly defined, the entrance to the larynx is pronounced and is located between the epiglottis on one side and the thickening on the other. From the middle of the 8th week of the prenatal development period, two parts of the pharynx become clear: cranial, wide – oral and caudal, located more dorsally than the larynx – laryngeal– pharynx. The lumen of larynx and pharynx is 3 times smaller than the lumen of the oral part of the pharynx. During the 9th week of embryonic development, the anterior posterior size of the nasal cavity (3.8 ± 0.28 mm) and the secondary palate are significantly increased due to the gradual growth in the horizontal direction of the palatal processes of the upper jaws. In this case, the upper part of the primary oral cavity is separated by the palatal processes of the upper jaws and becomes part of the nasal cavity, which behind ends with secondary hoans, irregular triangular shape, height 438,0 ± 0,6 mcm and width 672,0 ± 1,4 mcm By the end of the 9th week of intrauterine development, the hoans have a spherical shape of 780.0 ± 0.2 mcm in diameter and a height of 658.0 ± 0.4 mcm, which indicates the final separation of the secondary nasal cavity from the secondary oral cavity. Conclusion. The study results showed that in the dynamics of general pharyngeal formation there was a craniocaudal gradient of development, where the caudal border gradually shifts along the vertical axis throughout the prefetus period. A characteristic feature of this period of pharyngeal morphogenesis is the change in the structure of the epithelial lining. In some places, the dorsal wall of the laryngeal portion of the pharynx is replaced by a cylindrical three–layered epithelium by a four–layered cylindrical epithelium.

Keywords: pharynx, morphogenesis, prefetus, human

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