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5. The typology of growth processes of the male skull

The typology of growth processes of the male skull

Pestryakov A.N., Grigorieva O.M.

Institute of Ethnology and Anthropology, RAS, Moscow

Abstract

Craniological series are very heterogeneous regarding the type of growth processes of the skull. This is indicated by low, often inaccurate (in rare cases even negative) values of correlation coefficients between the three main diameters of the cranium in most of the studied series (or even complete absence of correlation), which is contrary to natural growth trends dictated by Pascal’s law. According to this law, the pressure of the growing brain on the internal surface of the cranium through cranial fluid must be distributed in all directions without change. Here we presented one method of separation of cranial series into fragments having distinct types of growth processes of the skull. The dendrogram was constructed using ratio values of the basic diameters: transverse to longitudinal (CI), vertical to longitudinal and vertical to transverse. Each cluster of the dendrogram represents a fraction of the series in which correlation among diameter values of the cranium is strongest. This is manifested through increase in the correlation coefficients and increase in the degree of harmonization of growth processes, which is the arithmetic average value of these correlation coefficients. A similar analysis is done for seven cranial series from geographically remote regions. Each of the studied cranial series was divided into two or three distinct clusters, corresponding to different fractions. These fractions were characterized by more consistent growth of the three diameters of the skull, compared to the original cranial series, and differed from each other by the type of growth processes. Usually the fraction of each of the series differed significantly from each other by the cranium shape, but not its absolute value. Most often selected fractions differ in transverse and vertical diameters, i.e. in one faction the skulls are broader and have smaller vertical diameter, in the other fraction they are narrower, but more vertically elongated. Thus, one faction tends to include more brachycephalic skulls with lower cranial vault, the other fraction consists of more dolichocephalic skulls with higher cranial vault.

Keywords

craniology, skull, growth processes, dendrogram, correlation analysis

Цит.: Pestryakov A.N., Grigorieva O.M. The typology of growth processes of the male skull // Moscow University Anthropology Bulletin (Vestnik Moskovskogo Universiteta. Seria XXIII. Antropologia), 2017; 1/2017; с. 89-102