Cranial Capacity in an Adult Sri Lankan Population: Sexual Dimorphism and Ethnic Diversity

Cranial capacity exerts a close correlation with the volume of the brain. A large body of evidence shows a clear racial variation in cranial dimensions. Therefore detailed knowledge of the population specific data on biometric features of the cranial cavity is important in the study and comparison of the crania of populations from different racial backgrounds, assessing growth and development of an individual and in the diagnosis of any abnormalities of cranial size and shape. Despite its significance, little is known concerning the cranial capacity in Sri Lankans. Hence, the present study was undertaken to establish the cranial capacity in an adult Sri Lankan population. A total of 210 subjects with an age span of 20-23 years were included in the study. The cranial length, breadth and auricular head height of the subjects were recorded using a digital sliding caliper and Todd’s head spanner capable of measuring to the nearest 0.01mm. The cranial capacity was calculated using external dimensions of the skulls (Lee & Pearson, 1901; Williams et al., 2000). The findings of the study indicated significant sexual differences in the mean cranial capacity (male: 1421.12 ± 171.69, female: 1300.95 ± 158.18). Positive correlations between cranial capacity and cranial dimensions were observed. Linear regression models for the prediction of cranial capacity were formulated for both sexes. The results of this study highlight the racial and sexual differences in cranial capacity in an adult Sri Lankan population. The data will be of immense use in clinical, medico-legal, anthropological and archeological studies.