Figure 1. Construction of finite element models of cranial dorsal regions (red outlines) in (1) Homalocephale colathoceros and (2) adult Pachycephalosaurus wyomingensis. Arrows represent the direction of collision forces applied to a sagittal-section finite element mesh for Homalocephale (3), and a 3D mesh (4) for Pachycephalosaurus, shown in orthogonal view.