The neural crest has long attracted the attention of evolutionary biologists and, more recently, clinical specialists, as research in recent decades has significantly expanded the boundaries of knowledge about the involvement of neural crest and neural crest cells in the development of human pathology. The neural crest and neural crest cells are a unique evolutionarily based embryonic structure. Its discovery completely changed the view of the process of embryogenesis. Knowledge of neural crest development sheds light on many of the most «established» questions of developmental biology and evolution. Our article will reflect on the historical stages of the discovery and study of the neural crest and the impact of this discovery on entrenched ideas about germ layer specificity and the theory of germ layers – the reasoning of the neural crest as the fourth germ layer. The aim of this review is to describe the history of the discovery and study of neural crest and neural crest cells based on an analysis of the literature. In writing this article, an analysis of the scientific literature was conducted using the search terms «neural crest», «neural crest cells», «neural crest cell morphology», «germinal layers» and «embryonic development» in the computer databases PubMed, Scopus, Web of Science, and eLibrary. The depth of the analytical search corresponds to the period of the discovery of the neural crest and the first mention of the neural crest as an embryonic morphological structure in the scientific literature. The information presented confirms the high interest of research scientists and clinical specialists in the study of neural crest and neural crest cells. The involvement of neural crest cells in the formation of somatic and musculoskeletal pathologies has received particular attention in recent decades. The literature sources are represented by 169 full-text manuscripts and monographs mainly in English. Conclusions. Neural crest and neural crest cells are unique evolutionary structures. Regularities of formation, reasons which condition migration, differentiation, interaction of neural crest cells with other structures during embryogenesis as well as their potential, which is realized in postnatal period, continue to be the subject of research up to now.

Idiopathic scoliosis is a common disease of the musculoskeletal system, affecting 2–3% of children and adolescents worldwide. The etiology and pathogenesis of scoliotic spinal deformity have not yet been disclosed, despite numerous long-term studies. Animal modeling of scoliosis can become the basis for studying possible etiological factors and pathogenetic mechanisms of the formation of the pathology in question and the prospects for possible treatment of scoliosis in the future. To date, many different types of models of scoliotic disease have been created and studied. The purpose of this review was to analyze the literature data on animal modeling of scoliosis in order to understand the etiological factor of idiopathic scoliosis in humans. Material and methods. The review was carried out using databases of electronic information resources PubMed (MEDLINE), Scopus, eLibrary.ru. The analysis of scientific literature was carried out according to the search words: “idiopathic scoliosis”, “experimental model of scoliosis”, “animal model of scoliosis”, “mechanical models of scoliosis”, “pineal gland resection models”, “genetic models of scoliosis”. Results. The analysis of scientific literature data confirms the high importance of experimental animal models of scoliosis for the study of the etiology of idiopathic scoliosis. The review summarizes and analyzes data on the main directions of modeling scoliotic deformity: mechanical, neuroendocrine and genetic models. Conclusions. The models of scoliosis presented in the literature have been implemented with varying degrees of success and have not been able to clarify the etiology of spinal pathology, but they are a useful tool for testing interventions aimed at correcting and preventing deformity. The development of an optimal experimental model of scoliosis in animals will further overcome the existing limitations in determining the etiological factor of idiopathic scoliosis and describe the processes of disease development characteristic of humans.

Introduction Blount's disease is a severe pediatric pathology of the musculoskeletal system. The condition is characterized by impaired growth and development of the proximal medial tibia and epiphysis, leading to varus deformity of the knee joint. Blount's disease is not just a cosmetic defect, but a serious orthopaedic condition accompanied by a gait disorder in a child. Patients with Blount's disease need surgical correction followed by longterm rehabilitation and can develop recurrence. The etiology of Blount's disease is unknown. Varus deformity of the knee joint is diagnosed in children all over the world, but studies on this pathology are few. There is a paucity of publications in the modern Russian literature reporting the pathology. The objective was review the literature on the classification, diagnosis, etiology and treatment of Blount's disease. Material and methods Electronic databases of PubMed, Scopus, eLibrary were used to source literature on the topic. Results Blount's disease has been shown to be characterized by disordered growth of the medial aspect of the proximal tibial physis and epiphysis that results in a three-dimensional deformity of the lower limb. In recent years, significant progress has been made in the diagnosis and surgical treatment of the cohort of patients. The etiology of Blount disease is unknown, and it is currently thought to result from a multifactorial combination of hereditary, humoral, biomechanical, and developmental factors. Conclusion Genetic predisposition has been postulated in the development of Blount's disease in many studies. Multiple factors such as ethnicity, obesity and early walking age are thought to be the contributing elements to this disease. To understand the key factor of the disease, further study of the hereditary nature of this pathology is necessary.

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Цель исследования: разработать способ закрытия дефекта скорлупы оплодотворенного яйца для проведения экспериментальных исследований на основании анализа анатомо-физиологических параметров завершающегося эмбриогенеза. Проведен анализ способов закрытия дефектов скорлупы оплодотворенного яйца и особенностей развития куриного эмбриона после закрытия дефекта скорлупы. Разработан оригинальный способ закрытия дефекта скорлупы оплодотворенного яйца для проведения экспериментальных исследований (получен патент). Проведена оценка жизнеспособности куриного эмбриона после закрытия дефекта скорлупы разработанным способом с использованием классификации Гамбургера-Гамильтона. Проводилось анатомо-физиологическое сравнение эмбрионов экспериментальной группы с параметрами развития при нормальном эмбриогенезе на 7-е, 13-е и 17-е сутки инкубации. В результате проведенного исследования апробирован разработанный авторами способ закрытия дефекта скорлупы оплодотворенного куриного яйца (силиконовой крышечкой). Полученные данные свидетельствуют о физиологическом развитии цыплят экспериментальной группы, что позволяет осуществлять наблюдение за развивающимся птенцом в течение не менее 17 суток. Проведена сравнительная характеристика анатомо-физиологических параметров эмбрионов экспериментальной группы и группы сравнения на основе классификации Гамбургера-Гамильтона, которая не выявила различий в развитии куриных эмбрионов в указанные сроки эксперимента. Ключевые слова: способ закрытия дефекта скорлупы яйца, жизнеспособность куриного эмбриона после закрытия дефекта скорлупы яйца, развитие куриного эмбриона, дефект скорлупы яйца, эмбриогенез.