Intermastoid distance as a criterion for determining the sex of the human skull

Abstract

Annotation. The mastoid processes of the temporal bones are of great interest from the point of view of determining the sex of whole skulls and their fragments. The researchers established sex differences in the linear dimensions of the mastoid processes, the shape and dimensions of the mastoid triangle, and the length of the intermastoidale distance. By discriminant function analysis, it was determined that the intermastoidale distance is one of the best indicators for determining the gender of the skull. At the same time, previous studies of the sex difference in the intermastoidale distance did not consider the relationship of this indicator with morphometric parameters characterizing the size of the skull. The purpose of this study is to establish the patterns of individual variability of the intermastoidale distance, namely, its relationship with the variability of the width of the skull base, the distance between asterions and the width of the cerebral cranium (transverse diameter of the skull). The study was conducted on 55 skulls (35 male and 20 female) from the craniological collection of the Department of Human Anatomy of KhNMU. Correspondence of the distribution of morphometric indicators to the normal distribution was determined using the Kolmogorov-Smirnov test with the Lilliefors correction. Statistical processing of measurement results was carried out using Excel 10 and Statistica 7 software packages. It was established that the intermastoidale distance in men is significantly greater than in women (M±s: 108,0±5,7 and 98±1,6, respectively; p<0.05). This is explained by the larger size of the male skull compared to the female one and the peculiarities of the constitution of male and female organisms. In men, there are statistical relationships between the intermastoidale distance and the width of the base of the skull (y = 0.5x + 41.0; r = 0.6; ); between the intermastoidale distance and the width of the cerebral part of the skull (y=0,4x+52,4; r=0,4); between the intermastoidale distance and the distance between asterions (y=0,6x+41,8; r=0,4) are noticeable and statistically significant (p<0.05). At the same time, in women they are small and statistically insignificant (respectively y=0,1x+87,4; r=0,3; y=0,1x+88,1; r=0,2; y=0,2x+74.8; r=0,3, p>0,05). The difference in the strength of the correlation between the studied parameters in male and female skulls may indicate the influence of various factors on the degree of the intermastoidale distance relationships with the studied skull dimensions depending on sex. We propose to consider the strong positive correlation between the intermastoidale distance and the width of the skull base established in this study as a factor that will allow for a qualitative (significant) increase in the accuracy of skull sex determination.