[Morphometric variability of precuneus in relation to gender and the hemisphere of human brain].

Precuneus, a quadrangular gyms of the medial surface of the human parietal lobe, is bound by three primary brain sulci and by superior hemispheric border. Precise encephalometric data about precuneus are important in the studies of brain lateralization, sex dimorphism, and brain functions in general. In this study, total and visible (exstrasulcal) surface area of the precuneus were measured on 50 brains of the adult persons (31 male, and 29 female), together with the investigation of its relationship to the side (left/right) and gender (sex dimorphism). The average total surface area of the precuneus was 16.07 cm2 on the right (males 16.44 cm2, females 15.27 cm2), and 15.44 cm2 on the left (males 15.67 cm2, females 14.62 cm2). The average visible (extrasulcal) surface area of cortex of precuneus was 9.97 cm2 on the left (males 10.75 cm2, females 8.91 cm2), and 9.38 cm2 on the right (males 10.25 cm2, females 8.19 cm2). Exstrasulcal surface area of the left precuneus was larger, by 0.59 cm on the average, which was not statistically significant. Total surface area of precuneus of males was significantly larger on the right (16.44 cm2) (p<0.01) than on the left (15.67 cm2). In females it was also larger on the right (15.27 cm2) than on the left (14.62 cm2), but with no statistical significance. Visible (exstrasulcal) surface area of both, (left and right precuneus of males), was highly significantly larger in comparison with the females (p<0.001). The obtained results and other facts suggested that sex dimorphism of human brain, including precuneus, was present, but not always easily observable, studied or proven in all the details.