Cephalic Index

A measurement technique used to define the relationship between the length and breadth of a human skull. The breadth of the skull is expressed as a percentage of the length and the ratio is figured as the maximum breadth to the maximum length, measured from a point just above the eyebrow ridges, multiplied by 100. This produces an index which defines the skull as round-headed (brachycephalic; a reading above 80), long-headed (dolichocephalic; a reading below 75), or in-between (meso- or mesaticephalic; a reading between 75-80). It is an important anthropological tool though it is now recognized that other methods of measurement are needed to compare skull shapes adequately.

Combination of two skull measurements, L (maximum cranial length) and B (maximum cranial breadth). The index describes the overall proportions of the cranium (brain box); see brachycephalic, dolichocephalic. In the past, it was used alone to assess genetic differences between groups of human skeletal material (see skeleton). Nowadays it is recognized that far more measurements are needed to compare skull shapes adequately.