The roughness of the supranasal region--a morphological sex trait

The supranasal region often attracts attention by a remarkable rough and jagged quality of the bony surface caused by an irregular supranasal suture and additional holes and pores. Some authors point out that there is a positive relation between the supranasal suture, the superciliar arches, and the forehead contour. For this a relation to sex is conceivable. This present study was done to prove the value of this morphological trait for sexing skulls.A total of 80 human skulls of known sex (40 females, 40 males) were collected from autopsy material used in anatomy teaching classes and from forensic cases. The mean age of the female sample was 70.98 years (minimum 38, maximum 93), that of the male sample was 74.10 years (minimum 57, maximum 99). To quantify the roughness of the supranasal region the calculation of the box-counting dimension was used. The results were normally distributed in both, the male and female group. The male dimension values were well grouped (maximum 1.51111, minimum 0.98765, mean 1.26159, S.D. 0.12268, 95% CI 1.22236-1.26604) whereas the female showed a wide range (maximum 1.46744, minimum 0.44755, mean 1.15052, S.D. 0.21388, 95% CI 1.08212-1.21892), widely overlapping the male range. Statistical analysis showed that there was a less than 1% probability that the female box-counting dimension was lower than the male by chance (P-value 0.00593). For this results the admission of the trait 'quality of the supranasal region' into a catalogue of features regarding morphognostic sex determination following the scheme: hyperfemininity: very smooth and regular--femininity: more smooth and regular--indifferent--masculinity: more rough and irregular--hypermasculinity: very rough and irregular, seems to be justified.