Peculiarities of the parietal bones of the vault of the human skull structure and shape, taking into account sex and craniotype

Abstract

The development of neurosurgery and the increase in requirements for the performance of surgical approaches performed through the bones of the skull vault lead to the formation of new requests for detailing and clarification of the craniometric characteristics of the parietal bones. The purpose of our study is to establish the features of the shape and other spatial indicators of the parietal bones of the skull of a mature person, taking into account sex and certain types of craniotype. The study was conducted on 130 studied preparations of bone structures of the head of adults from the collected collection of the Department of Normal Anatomy of the Kharkiv National Medical University, in the amount of 82 bone preparations, including isolated parietal bones, as well as 48 tomograms obtained during the examination of patients. The basis for establishing a craniotype is the principle of calculating the cranial index. For statistical analysis, we used the programs Statistica 13.5.0.17 (trial version) and Microsoft Excel of the corporate package MS 365. To establish the peculiarities of the structure and shape of the parietal bones, the following craniometric indicators were determined: the length and width of the parietal tubers, the parietal chord and the arch, calculated the curvature index of the parietal bone. The obtained data were analyzed for mature people of different genders and three established craniotypes. It has been established that brachycephals are characterized by an expanded and expanded form of the parietal bones, which is associated with the predominance of the transverse dimensions of the entire cerebral skull. For mesocephals, the most typical intermediate- average form depending on the values of the cranial index. Dolichocephals have an elongated and narrowed form of the parietal bones, which is combined with general changes in the cerebral skull. Additional linear parameters of the parietal bones are directly dependent on the established craniotype. The dolichocephalic type is characterized by maximum length values of parietal tubers: ¯x =18.43 mm (right) and ¯x =18.24 mm (left) with minimum width parameters: up to ¯x =15.71 mm and ¯x =15.02 mm. Representatives of the brachycranic type are characterized by the minimum indicators of the length of the parietal tubers: from ¯x =12.73 mm to ¯x =12.81 mm and the maximum indicators for the width - ¯x =23.52 mm (right) and ¯x =23.04 mm (left). The parietal chord, like the parietal arch, had a similar trend in the distribution of indicators, namely: an increase from dolichocrania to brachycrania. In men with a dolichocephalic type of skull structure, the average values of these parameters were at the level of ¯x =108.2 mm (right) and 107.6 mm (left) for the parietal chord, and ¯x =114.2 mm and ¯x =113.2 mm for the parietal arcs In men with brachycranic type, the parietal chord reached - ¯x =116.6 mm (right) and ¯x =115.8 mm (left), and the parietal arch reached - ¯x =127.8 mm (right) and ¯x =126.9 mm ( left). In women, a similar principle of size distribution has been established, taking into account a small, 2-3 mm, general decrease in indicators compared to men. The curvature index of the parietal bones was determined: the maximum average values ¯x =83.00-83.58 were obtained in dolichocephals, the minimum values were ¯x =80.56-81.64 in brachycephals. This indicates an increase in the curvature of bones in brachycephals, given that the absolute value of the index is inversely proportional to the degree of curvature. Thus, the obtained data indicate a stable relationship between the craniotype of the skull and additional parameters of the parietal bones.