This paper investigates the relationship between the incidence of axonal injury and the tissue mechanics proauced by an impact to the head in an animal model. The data are drawn from an experimental model of brain injury using sheep where the dynamics of the head impact are measured. Measurements include impact force, head acceleration and subdural pressures. A preliminary finite element model of the sheep skull and brain is presented. Simulations of selected experiments are used to estimate mechanics of the brain tissue during the impact. The resulting injury in the brain tissue was mapped using amyloid precursor protein as a marker for injury. A comparison is made between the von Mises’ stresses predicted by the finite element model, and the incidence of injury in various regions of the brain. The results of the model suggest that a trend exists between high levels of stress and the incidence of injury. All experiments conformed to the Australian Code of Practice for the Care and Use of Animals for Scientific Purposes.