Simulating Mechanism of Brain Injury During Closed Head Impact

In this paper, we study the mechanics of the brain during closed head impact via numerical simulation. We propose a mathematical model of the human head, which consists of three layers: the rigid skull, the cerebrospinal fluid and the solid brain. The fluid behavior is governed by the Navier-Stokes equations, and the fluid and solid interact together according to the laws of mechanics. Numerical simulations are then performed on this model to simulate accident scenarios. Several theories have been proposed to explain whether the ensuing brain injury is dominantly located at the site of impact (coup injury) or at the site opposite to it (contrecoup injury). In particular, we investigate the positive pressure theory, the negative pressure theory, and the cerebrospinal fluid theory. The results of our numerical simulations together with pathological findings show that no one theory can explain the mechanics of the brain during the different types of accidents. We therefore highlight the accident scenarios under which each theory presents a consistent explanation of brain mechanics.