Morphoscopic predictors for sexual dimorphism of skulls

Objective: Morphological differences between sexes are also reflected in the skull bones, which can be used for sex determination of skulls. Our objectives were to observe the osteoscopic features of skulls and determine the frequency of characteristic female features in female skulls and the frequency of characteristic male features in male skulls in the observed sample; also to determine the prediction (effectiveness) of sex determination based on observed morphognostic (osteoscopic) features of the skulls and determine the most frequent and the least frequent morphognostic feature both in male and in female skulls in our tested sample. Methods and materials: The research was conducted on a sample of 211 macerated and degreased adult skulls (139 were male skulls and 72 were female skulls). Qualitative (osteoscopic) analysis included observation of the following: prominence of frontal tuber; prominence of superciliary arch and glabella; appearance of supraorbital margin; appearance of orbit; width of root of nose; prominence of mastoid process; contours of muscle insertions; size of teeth and face shape.         Results: Univariately, all ten observed morphognostic skull features showed statistically significant effect on sex determination, while prominence of superciliary arch and glabella proved to be the best morphognostic features with 90% accuracy, followed by prominence of muscle insertions with 82% accuracy, and prominence of mastoid process with 75% accuracy. Using multivariate binary logistic regression, we tested the effect of observed morphognostic features on sex determination and found that the only morphognostic features that had a statistically significant effect on sex determination were prominence of  superciliary arch and glabella and size of mastoid process. Multivariate effect of the prominence of muscle insertions on sex determination is borderline (p=0.052). Conclusion: Univariately, the greatest predictive effect for prediction of male sex is shown by the prominence of superciliary arch and glabella, prominence of muscle insertions and mastoid process. Multivariately, morphognostic features of prominence of superciliary arch and glabella, as well as the size of mastoid process show a statistically significant effect on sex determination. Effect of the prominence of muscle insertions is borderline. Key words: Skull, sexual dimorphism, osteoscopy, binary logistic regression