Abstract
The site-dependent load-deformation behavior of the human neurocranium and the load dissipation within the three-layered composite is not well understood. This study mechanically investigated 257 human frontal, temporal, parietal and occipital neurocranial bone samples at an age range of 2 to 94 years, using three-point bending tests. Samples were tested as full-thickness three-layered composites, as well as separated with both diploe attached and removed. Right temporal samples were the thinnest samples of all tested regions (median<5 mm; p<0.001) and withstood lowest failure loads (median<762 N; p<0.001). Outer tables were thicker and showed higher failure loads (median 2.4 mm; median 264 N) than inner tables (median 1.7 mm, p<0.001; median 132 N, p=0.003). The presence of diploe attached to outer and inner tables led to a significant reduction in bending strength (with diploe: median<60 MPa; without diploe: median>90 MPa, p<0.001). Composites (r=0.243, p=0.011) and inner tables with attached diploe (r=0.214, p=0.032) revealed positive correlations between sample thickness and age. The three-layered composite is four times more load-resistant compared to the outer table and eight times more compared to the inner table.