FEATURES OF MORPHOGENESIS OF THE BONES OF THE HUMAN ORBIT.

OBJECTIVE: The aim: To find out the sources of origin, the chronology of ossification, the peculiarities of age-related topographical and anatomical changes in the bones of the human orbit. PATIENTS AND METHODS: Materials and methods: The research was carried out on the specimens of 18 human embryos and prefetuses aged from 4th to 12th weeks of intrauterine development and 12 human fetuses aged from 4th to 9th months which were studied by microscopic examination and 3D reconstruction. RESULTS: Results: The first signs of osteogenesis around the main nervous and visceral contents of the orbit rudiment are observed in 6-week-old embryos in the form of seven cartilaginous bone models. The first signs of ossification in the region of the orbit are found in the maxilla. During the 6th month of intrauterine development, intensive processes of ossification of the frontal, sphenoidal, ethmoidal bones and maxilla are noticeable. From the beginning of the fetal pe¬riod of human ontogenesis, the ossification of bone rudiments that form the walls of the orbit continues. The processes of ossification of the structures of the sphenoidal bone continue, which leads to morphological transformations of the orbit in 5-month-old fetuses - it is separated from the sphenopalatine and infratemporal fossae by a bone layer, the optic canal is formed, and in 6-month-old fetuses, processes of ossification of the frontal, sphenoidal and ethmoidal bones and maxilla occur, Müller's muscle changes its structure to a fibrous one. CONCLUSION: Conclusions: Critical periods of the orbit development are the 6th month of prenatal ontogenesis and the 8th month.

PECULIARITIES OF THE HUMAN MAXILLA MORPHOGENESIS.

OBJECTIVE: The aim: To find out the sources of formation and the chronological sequence of the morphogenesis of the maxilla at the early stages of human ontogenesis. PATIENTS AND METHODS: Materials and methods: 14 series of consecutive histological specimens of human embryos and prefetuses (4,0-66,0 mm of parietal-coccygeal length) aged from 4 to 11 weeks of intrauterine development with the use of a complex of modern morphological methods of investigation (anthropometry, morphometry, microscopy, and 3D computer reconstruction) were studied. RESULTS: Results: On the basis of a complex of morphological research methods, data were obtained that made it possible to establish the general patterns of development of the human maxilla: separation of the pharyngeal apparatus (4th week), convergence and fusion of the jaw processes (5-8th weeks), formation of tooth buds (7-8th weeks), which allows considering the specified periods as critical in the formation of possible anomalies in the facial part of the skull. At the same time, a tendency of heterochrony of morphological transformations in the maxilla and maxilla was revealed. CONCLUSION: Conclusions: 1. At the beginning of the 4th week of intrauterine development, 3 pairs of pharyngeal arches are formed. Detachment of the mandibular and maxillary processes of the mandibular pharyngeal arch is planned. 2. During the 7th week of intrauterine development, the maximum convergence of the maxillary processes with the lateral and medial nasals occurs, and in embryos of 20.0 mm PCL grow with the frontal process, forming the maxilla and upper lip. During the 8th week of intrauterine development, the bone base of the jaws is modeled as a result of the increase in the size of osteogenic islands and their fusion, alveolar processes are formed. 3. During the 9-10th weeks of intrauterine development, the primary palate is formed as a result of the fusion of the palatine processes. 4. At the 11th week of intrauterine development, the bone base models both jaws. Due to the processes of histogenesis of the soft tissues of the maxillofacial apparatus, the face acquires anthropomorphic definitive human features.

PECULIARITIES OF THE SOURCES OF ORIGIN AND MORPHOGENESIS OF THE HUMAN MANDIBLE.

OBJECTIVE: The aim: To determine the sources and terms of origin, developmental peculiarities and dynamics of ossification of the mandible during the prenatal period of human ontogenesis. PATIENTS AND METHODS: Materials and methods: The research was carried out on the specimens of 30 embryos, 30 pre-fetuses and 60 human fetuses at the period from the 9th to the 12th weeks of the intrauterine development, which were studied by microscopic examination. Three-dimensional computer reconstructions of the human pre-fetal head were made. RESULTS: Results: During the 7th week of development the maxillary processes maximum approach the lateral and medial nasal ones; in pre-fetuses 20,0 mm of PCL they join the frontal spindle forming the facial structures (upper jaw and lip, vestibule of the oral cavity, rudiments of dental laminas, and rudiments of dental buds in its distal portions). Osteogenous islets, rudiments of the mimic and masticatory muscles, blood vessels are formed. During the 8th week of development the osseous tissue of the mandible is formed, the alveolar processes are formed. The oral and nasal cavities are isolated in 9-10-week pre-fetuses, the mass of the osseous tissue increases in both jaws, the enamel organs are detached, the angles and rami formed by the hyaline cartilaginous tissue of the mandible are determined, the rudiments of the temporomandibular joints are already seen. During the 11th week of development the osseous base of both jaws become formed. Till the end of the 12th week the osseous tissue begins to replace the hyaline cartilage of the mandibular rami, and the articular heads are formed in the portion of their proximal ends. CONCLUSION: Conclusions: The mandible in its development is known to be characterized by intra-cartilaginous formation of the bone which starts from the ends of the cartilage gradually displaced by the osseous tissue. It is indicated that both jaws in pre-fetuses 37,0 and 42,0 mm of PCL are presented by the typical cartilaginous tissue, and in pre-fetuses 45,0-50,0 mm of PCL the osseous tissue is already available replacing the cartilaginous one.

DEVELOPMENT OF THE INNER NASAL CAVITY IN ANIMALS IN PHYLO- AND ONTOGENESIS: FUNCTIONAL ANATOMIC SIGNIFICANCE IN THE DEVELOPMENT PERIOD ROZWÓJ WEWNETRZNEJ JAMY NOSOWEJ U ZWIERZAT W FILO- I ONTOGENEZIE: CZYNNOSCIOWE I ANATOMICZNE ZNACZENIE W OKRESIE ROZWOJOWYM.

OBJECTIVE: Іntroduction: Main functions of the inner nose in humans are respiration and olfaction. Therefore, human needs a large surface of inhalable and exhalable air contact, warming and moistening. Importance of these organs in animals in phylogenesis before and after the secondary palate development can explain their anatomic and functional designation. The aim is to find out the functional significance of some anatomic formations of the inner nose and their development peculiarities in phylo-and ontogenesis. PATIENTS AND METHODS: Materials and methods: We used a comparative anatomy method where we compared well-known facts of different animals' development before and after secondary palate formation in phylo- and ontogenesis. RESULTS: Review: Olfactory organ in lower vertebrates develops as canal with two openings through which as a result of water penetration the olfactory ability increases. Sinuses formation in animals happens after secondary palate formation. Secondary palate in embryo develops by second month of development, and sinuses' development begins on the 3-4 month. As a result, upper jaws and facial skull became stronger. Importance of mucous and lacrimal glands of the nose cavity and mucous glands of mouth received new functions of animal and vegetable food digestion. CONCLUSION: Conclusions: development of the secondary palate in warm-blooded vertebrates changed (limited) functional applicability of the lacrimal gland and nasolacrimal canal, mucous glands of nose and vegetative innervation. Groups of lacrimal, mucous glands of nose and mouth are unified system of primary, neurosecretory reaction to environment.

Peculiarities of prenatal vagina morphogenesis.

OBJECTIVE: Introduction: The rapid development of perinatal gynecology requires from the anatomists comprehensive studies of the patterns of prenatal morphogenesis and the development of topographic and anatomical relationships of female reproductive organs in the human fetuses of different age groups. The aim: To study the development and formation of the vaginal topography in the prenatal period of human ontogenesis. PATIENTS AND METHODS: Materials and methods: The study has been conducted based on 23 series of histological and topographic-anatomical sections of human prefetuses aged 9-12 weeks with 31.0-80.0 mm of crown-rump length (CRL) and 83 specimens of female human fetuses aged 4-9 months with 81.0-345.0 mm of CRL by means of a complex of adequate morphological methods of investigation. RESULTS: Results and conclusions: Vaginal formation occurs during the 9th week of embryogenesis (prefetuses of 31.0-41.0 mm of CRL) due to the fusion of two different embryonic structures: mesodermal paramesonephral ducts and endodermal urogenital sinus. In this case, the caudal regions of the paramesonephral ducts are transformed into the uterus and the superior two thirds of the vagina, and the inferior third of the vagina develops from the urogenital sinus. Common uterovaginal canal, divided into right and left cavities by mesenchymal septum, is formed in the female prefetuses of 38.0-43.0 mm of CRL due to the fusion of the caudal regions of the paramesonephral ducts in the area of the posterior wall of the urogenital sinus. Complete dissolving of the septum of the uterovaginal canal occurs in prefetuses of 55.0-58.0 mm of CRL. The anterior and posterior vaginal vaults of the same depth are formed in 5-month-old fetuses. Canalization of vagina in the caudo-cranial direction is observed in the fetuses of 170.0-185.0 mm of CRL, with no clear boundary between the uterovaginal canal and the urogenital sinus. The vaginal epithelium in the upper third part originates from the uterovaginal canal, and in the lower two thirds of the vagina - from the urogenital sinus. In the 6-month-old fetuses there was detected the variability of the shape of the superior, middle and inferior third of the vagina, namely: oval (5 cases), elongated-oval (2 cases), stellate (1 case); in the lower third, the H-shaped form was predominantly found (6 fetuses). The proliferation of the hymen membrane occurs in fetuses of 220.0-245.0 mm of CRL. The absence of timely proliferation of the hymen membrane can lead to its atresia, and its premature proliferation causes the appearance of transverse vaginal septa.