Analysis of the motion of rat head in impact acceleration injury tests

The kinematics of two head injury models with impact acceleration that produced severe and mild diffuse axonal injury in rats were investigated. The animals were instrumented with two triaxial accelerometers and the vertical motion was also recorded with high speed digital photography. The maximum linear and angular velocities in the severe injury model (7.2 m/s and 100 rad/s) were 4.0 and 3.3 times higher than the mild injury model showing that both linear and angular components of the motion may contribute to the severity of diffuse axonal injury. The results of this study can be used to develop an injury criterion for mild to severe diffuse axonal injury.