Mechanism of an infantile subdural hematoma has been controversial. It is not known whether the injury occurs in physical abuse or accident, or both. To identify the influence of surface characteristic on intracranial brain motion in backward fall, we developed a dummy which could visualize the relative motion between skull and brain, and conducted falling experiment by changing surfaces. As the results of the experiments, intracranial brain motion was not affected by the differences of the surface characteristics.
