Dimensions of tympanic cavity structures of the human fetuses nine months of the development

Abstract

Introduction. The influence of a number of adverse factors lead to a significant increase in the percentage of non-pregnancy in recent decades. For the nurse of premature infants of all ages, currently the doctors of various specialties are ingaged, including otolaryngologists. As a result, the prevention of disability and the timely rehabilitation of such children are becoming an important problem for them. That’s why the study of embryological aspects of the development of the middle ear, its anatomy and topographic anatomy in the fetuses remains actual. The aim of the study. To study of the topographic anatomical features of the tympanic cavity in the fetuses of 9 months of fetal development and to substantiate the morphological interconnection of its forming processes with adjacent structures. Materials and methods. The study was performed on 7 human fetuses of 311.0-345.0 mm of parietal-coccygeal length (PCL). In the course of the study the following methods were used: fine anatomization of the middle ear and adjacent areas under the control of binocular enlarging lens; macro- and microscopy; morphometry; photomacrography of the “OLIMPUS μ 1000 All-weather 10.0 Mpix” digital camera. Result and discussion. The canal of the internal carotid artery passes at an angle of 55 ° to the base of the skull and lies on the inferior surface of the temporal bone, which during this period of the development is in the form of a triangular pyramid. The diameter of the canal of the internal carotid artery is 2,56 ± 0,04 mm. The width of the jugular fossa - 7,25 ± 0,18 mm, length - 9,50 ± 0,24 mm. Dimensions of the tympanic cavity: length from below - 7,60 ± 0,19 mm, length at the promontory level - 9,75 ± 0,18 mm, length from above - 7,40 ± 0,23 mm. Vertical dimensions of the tympanic cavity: in front - 8,15 ± 0,19 mm, opposite the 64 Natural Science Readings (May 28-30, 2020, Bratislava) promontory - 9,68 ± 0,34 mm, behind - 7,15 ± 0,17 mm. The width of the tympanic cavity: in the inferior anterior portion - 2,22 ± 0,05 mm, in the inferior posterior portion - 5,22 ± 0,12 mm, in the anterior superior portion - 3,85 ± 0,15 mm, in the posterior superior portion - 4,82 ± 0,19 mm. The thickness of the walls of the tympanic cavity is: the superior – 0,99 ± 0,03 mm, the superior – 0,62 ± 0,03 mm, the inferior – 0,72 ± 0,02 mm. The long diameter of the annulus tympanicus with tympanic membrane is 8,12 ± 0,19 mm, the short diameter is 7,25 ± 0,23 mm. Discussion. During this period the formation of the inferior and anterior wall of the tympanic cavity continues. The internal carotid artery and jugular bulb participate in this process. Tympanic holes of the auditory tube continue to move from the bottom upwards tympanic cavity to the upwards. Conclusions. 1. The inferior and anterior walls of the tympanic cavity, epitympanum continue to form from the fetuses of this age. 2. The tympanic openings of the auditory tubes begin to move from the inferior part of the tympanum to the upwards. 3. The identified features are important in improving the technology and the adequacy of surgical treatment and manipulations in premature babies.