The results of a head injury model development program are presented. They include a description of the model's features and its capabilities for simulating direct and indirect impact forces. The model's validity is discussed in terms of level of confidence and verification. Skull bone response and brain response are presented for a variety of dynamic simulations. The scope and limitations imposed by the assumption of linearity are discussed. The results demonstrate that while some minor changes appear indicated, the model predictions yield useful insight into the mechanical causes of skull and brain injury.