Cerebral Blood Vessel Rupture During Head Impacts: A Parametric Study on Properties of SAS Trabeculae and Pia Mater

Blunt head impacts cause relative motion between the brain and skull. This increases the normal and shear stresses in the (skull/brain) interface region, which leads to the rupture of cerebral blood vessels and in particular bridging veins. Mechanical properties of meningeal layers, in particular, subarachnoid space (SAS) trabeculae and the pia mater are not well established in the literature and could have a wide range depending on an individual. In our previous studies, knowing that SAS trabeculae and pia mater are collagen-based structures, these mechanical properties have been estimated using the properties of similar collagen based tissues. However, recent study Xin Jin et al. (2008), suggests that the mechanical properties of trabeculae and the pia matter are significantly less than a collagen-based tissue. Therefore, the goal of this study is to investigate the effect of the mechanical properties of these tissue on the stress and strain of the neighboring tissues when the head is subjected to a blunt impact. Specifically, the objectives of this study is to determine the stress/strain changes of the cerebral blood vessels as a function of the mechanical properties of the SAS trabeculae and pia mater, when the loading and the boundary conditions of the local model are kept the same. Note that the variation of the properties of these tissues affects the failure of cerebral blood vessels which leads to traumatic brain injury.