[Asymmetry in artificially deformed skulls from a Protobulgarian mass grave of the 9th century].

A series of 18 skulls with pronounced asymmetry, picked up out of a total of 52 artificially deformed and accordingly restored skulls are studied. It is a matter of material discovered in a circular tomb near by the village of Devnja, dating back to the end of the 9th century. To obtain metrical determination of the asymmetry, the authors performed measurements of chords, resp. arches between the anthropological points sphenion and asterion, as well as of the distance from the latter and from the porion on either side up to the glabella, inion, bregma and lambda. Besides the 18 sizes directly recorded, 18 chords constructed on the craniograms (three per skull) mainly between the above mentioned points were also utilized. For each dimension the absolute differences between left and right, the mean value of the differences and the asymmetry index after Duncker were calculated. Using the method outlined, an accurate and quantitative determination was made of the asymmetry both in the occipito-parietal and temporo-clinoidal parts of the skull (compensatory and persisting asymmetry). It is demonstrated that the discrepancies between some of the size values established in individual skulls, and the skull asymmetry, recorded scopically with other measurements, are due to displacements of the anthropological points (sphenion, asterion, inion), produced by differences in growth rate and size of bones. The arrested development of bones and the resulting depressions along their surfaces under the effect of the artificial deformation dressing are of utmost importance for the processes developing within the deformed skulls.