Background: Studying the human embryonic and fetal organ systems development patterns and determining their quantitative indicators is of scientific and practical importance in medicine and health in every nation.
Distortions and pathologies during the development of the embryo are the causes of congenital disabilities. Among the congenital malformations, facial malformations are the 3rd place, including cleft lip and palate in 70% and Srouzon's syndrome in 30%. In addition, abnormalities due to changes in the size, shape, and position of the jaw are also mentioned in the 2021.04.21 issue of Morphology magazine in the study "Morphometric parameters of the bones of the skull and face during the development of newborns and fetuses". In our country, Ariuntuul G (2005) determined that cleft lip and cleft palate occur at 0.76/1000 or 1 in 1314 live births, while Ayanga G (2012) found that it occurs at 1 in 1072 live births or 0.93/1000. Moreover, the eye cup dimensions of Mongolian fetuses aged 16 36 weeks have a positive linear relationship with the gestational age determined using ultrasound by Nandintsetseg B (2015) et al. Compared with the other countries, the eyecup is slightly wider, and the outer edge distance is similar, whereas the inner edge distance is shorter. Purpose: To summarize research work and determine the embryonic development of bones involved in the formation of the face and facial parts, the period of bone formation, the point of ossification, and the period of formation. Methods: During fetal development, human organ systems grow and develop at different rates but in a particular relationship. This feature of growth and development is also clearly observed in the structure of the head and facial bones, and the results of researchers who have studied this aspect are selected in the articles. Results: Embryonic and fetal development of bone are clinically significant not only from the point of view of its morphogenesis but also from the point of view of congenital disabilities. Conclusion In the analysis of the sources, most of the works on the prenatal period of the development of the same body have studied the development of specific structures of the face and facial area, such as the palatine bones and nasal bones, or have generally covered the development of particular systems in the embryo and fetus, and face, there are relatively few works that show the entire dynamics of growth and development of facial bones.

Result the subtypes and effectiveness of functional endoscopic sinus surgery(FESS) using a microdebrider Introduction: Chronic rhinitis in children has been on the rise in recent years, and polyps account for the majority of benign nasal cancers in children. Surgery is necessary when drug treatment is ineffective. We use pediatric rhinoplasty. Aimed at calculating the subtypes and effectiveness of Functional endoscopic sinus surgery(FESS) using a microdebrider. Material and methods: The survey was conducted between March and April 2020, based on the Otolaryngology Surgery Department of the National Center for Maternal and Child Health, using the cross-section of analytical design under Objectives 1 and 2 and the longitudinal design under Objective 3. Under Objectives 1 and 2, participants' information was collected from a pre-prepared questionnaire from their medical history. The questionnaire has four chapters that provide general information about the patient, clinical signs, surgical structure, and biopsy results. The pain was assessed by the “Sino-Nasal Outcome Test (SNOT-20)”. A total of 98 patients were included in the statistical analysis of the survey results using the STATA 15.0 program, and the results of the surgery were evaluated by 20 patients. Results: In children with chronic rhinitis, the SNOT20 test showed a statistically significant difference of 1.6 ± 0.6 before surgery and an average of 0.51 ± 0.11 after surgery. Conclusion: In chronic rhinitis, FESS with microdebrider surgery is an effective treatment for children.