Figure 12. Stress and strain in the dome of Stegoceras validum (UA 2).
A. Von Mises stresses (indicating closeness to yield) in a mid-sagittal section through the cranium of the pachycephalosaur Stegoceras validum. The highest stress within cancellous regions of the dome about 1 MPa, indicating a safety factor of 8–10 at the tested force. Stresses in compact bone surrounding the brain peak at 5 MPa, for a safety factor of 20–30. Constraints inflate stress artificially at the basal tubera and occipital condyle, and basicrainial and braincase stresses would be lower than depicted here. B. Von Mises stress and strain at 29 samples of a vertical transect through the dome. Strains are expressed in terms of safety factor: ultimate bone strain (0.6%) divided by the actual strain. Log10 values are used, because cortical safety factors approach 100 in some regions.