In the article the features of anatomical structure and microtopography of the lower jaw of fetus at the age of 14–18 weeks were discussed. The relevance of the research is due to the prevalence of congenital pathology of the maxillofacial region, the possibilities of its early prenatal diagnosis and correction in connection with the development of fetal surgery.The aim of the research is to get new data of the macromicroscopic anatomy and microtopography of the lower jaw in fetuses of 14–18 weeks.Material and methods. The object of the research was the lower jaw of 40 male and female fetuses at the age of 14–18 weeks. The research was carried out using morphological methods and the method of ultrasound scanning. The qualitative and quantitative characteristics of the lower jaw were studied.Results. The lower jaw of the fetus at the age of 14–18 weeks is already formed and has basic anatomical structures. The body, angle, ramus, condylar and coronoid processes, teeth anlages, which can be described on morphological preparations and studied using the method of ultrasound scanning, are defined in the lower jaw. In front of the lower jaw, soft tissues are located, their thickness varies from 2.1 to 3.9 mm. Behind the lower jaw, there is a slit space with a width of 0.3 to 1.5 mm, behind it the tongue and the oral part of the pharynx are situated. The latter has an irregular shape. In a fetus of 14-18 weeks, major salivary glands (parotid, sublingual and submandibular) are already formed and determined on different cuts. The length of the alveolar arch is 29.1±6.2 mm, the width of the lower jaw is 19.5±4.2 mm. At this time, the lower jaw can be presented by two anlages and a symphysis located along the median line. The symphysis on horizontal cut has a fusiform shape, it narrows to the outer and inner surfaces of the lower jaw. In the narrow part, its size varies from 0.1 to 0.4 mm, the extension in the central part is from 0.5 to 0.9 mm. In the lower jaw, the anlages of decidual teeth of an irregular shape are determined. The size of anlages varies from 1.3 to 2.3 mm, depending on the type of tooth. On some cuts under the anlage of primary tooth, it is possible to determine the anlage of permanent one. The significant bilateral and sex differences of human fetuses at the age of 14–18 weeks of intrauterine development were not revealed.Conclusion. The lower jaw of fetuses at the age of 14–18 weeks has all elements of the anatomical structure, with certain fetal features (incomplete accretion of the mandibular processes, anlages of decidual and permanent teeth, microtopographic relationships with adjacent anatomical structures). At this stage of development, there are no significant bilateral and sex differences. The use of various methodological approaches to the research of the qualitative and quantitative anatomy of the lower jaw makes it possible to detail and supplement the substantiation of approaches for fetal surgery.
Aim to describe the topographic and anatomical relationships of the fetal lower jaw and auricle in the mid-gestation period. Material and methods. The 110 mandibles of human fetuses of the second trimester were selected for the study and divided into groups by sex and age. The morphological techniques and the method of ultrasound scanning were used to determine the topographic relationships of the lower jaw and the fetal ear, the location of the central part of the auricle relative to the lower jaw (the line connecting the gnathion point and the external occipital protuberance) at different age periods. Results. During the mid-gestation period, with the growth of the fetus, the auricle normally shifts upward relative to the mandible. At the beginning of the study period, the auricle is located just below the angle of the lower jaw. Its central part (C) is below the line (AB) connecting the gnathion point and the external occipital protuberance. The perpendicular from the conditional center of the auricle to the line AB is half the diameter of the auricle 3.7 1.1 mm. In the second age group, the auricle is located at the level of the branch and angle of the lower jaw Its conditional center (C) is below the line AB and is of the diameter of the auricle 3.1 0.8 mm. By the end of the mid-gestation period, the auricle is displaced to the level of the processes of the lower jaw above the notch. Its central part is above line AB, the perpendicular from point C to line AB is 6.1 1.4 mm. Conclusion. The deviations in the formation of the topographic and anatomical relationships of the lower jaw and auricle of the fetus from 14 to 27 weeks of gestation can be additional criteria for the development of congenital fetal pathology and require the fetoabnormal alertness.
Objectives to describe the macromicroscopic anatomy of the nasal cavity in the intermediate fetal period of human ontogenesis. Material and methods. The object of the study was horizontal histotopograms of the nose of 15 fetuses of both genders at the age of 1922 weeks of the intermediate fetal period of ontogenesis. The study used the method of macromicroscopic preparation, the modified method of saw cuts according to N.I. Pirogov, and the histotopographic method. Results. On the horizontal histotopographic sections the external nose was shaped like a triangle. The structures of the external nose were covered with skin soldered to the underlying tissues. In soft tissues, there was a large accumulation of arterial and venous vessels, nerves, and glands. In the intermediate fetal period, the nasal passages had the shape of a triangle, with the base turned to the nasal part of the pharynx. It was found that the anterior-posterior size of the nasal septum in fetuses of the intermediate fetal period was 14.054.34 mm, with a range of fluctuations from 5.75 to 19.85 mm. The anterior-posterior size of the nasal septum in female fetuses was greater than the anterior-posterior size of the septum of male fetuses. The value of the width of the nasal septum was the maximum in the lower third, and reached up to 2.540.67 mm. The narrowest part of the nasal septum was its middle third, the value was 1.630.47 mm. The areas of the nasal passages had no bilateral differences. Conclusion. In the intermediate fetal period there is the establishment of qualitative and quantitative macromicroscopic anatomy of the nasal cavity. All the main structures are determined: the nasal septum, nasal conchs, mucosa, and blood vessels. Sexual differences begin to form, and there are no bilateral differences. Quantitative characteristics of the structures of the nasal cavity in fetuses can serve as a justification for early surgical intervention in choanal atresia.
Aim to obtain new data on the anatomy of the mandible of a human fetus aged 1923 weeks. Material and methods. The object of the study was 40 mandibles of human fetuses of both sexes aged from 19 to 23 weeks. The morphological method (macromicroscopic preparation; the method of saw cuts according to N.I. Pirogov; production of serial histotopograms) and the method of ultrasound scanning by the device VOLUSONS 10, RAB 6 RS sensor in 2D mode and in the "Skeleton" program (3D mode) were used. Results. In fetuses aged 1923 weeks the mandible represents a paired bone connected in the center by a symphysis. According to the shape of the body, it is possible to select wide and short, long and narrow mandibles in a ratio of 2 to 1, respectively 67% and 33%. The length of the alveolar arch is 52.4 5.6 mm (with a range of 45.360.2 mm), the angular width is 23.4 1.7 mm (with a range of 19.027.8 mm). The height of the branch at the cutting level was equal to 6.2 1.4 mm (with a range of 3.69.0 mm). On the anterior surface of the body, one chin opening is determined on both sides, at an average distance of 16.4 mm from the angle of the mandible and at a height of 2.2 mm. On the inner surface of the branch, the opening of the mandible is determined, located at a distance of 3.6 1.1 mm from the angle, 3.2 0.9 mm from the anterior edge of the branch, 4.1 1.2 mm from the posterior edge of the branch. In the second trimester of pregnancy, dental alveoli are determined in the mandibular dental arch of the fetus. Significant sex differences were found for the angle of the mandible (p 0.05). In girls, the angle was 141.1 10.1, in boys 129.5 9.4. Conclusion. The mandible of the fetus at the age of 1923 weeks is formed and has fetal characteristics. During this period, no significant bilateral differences were revealed, sexual differences start to form.
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