Effects of head rotational motion on brain deformation behavior were examined using a head physical model constructed from individual medical images of a head. The model consists of the parts reconstructed the skull, falx, cerebrospinal fluid (CSF) and brain, which represents an actual human head shape. Rotational impacts were applied around frontal axis of the model under the conditions in the case that maximum angular acceleration and angular velocity were controlled. As the results of experiments, shear strain in brain part and peak strain between skull and brain surfaces, which assumes strain at bridging veins, correlates strongly with peak change of angular velocity but correlates poorly with maximum angular acceleration which has been often proposed as a head injury criterion in rotational impact. Thus, peak change of angular velocity of a head should be included in the injury criterion in the case that rotational motion of a head occurs.
