HEAD KINEMATICS DURING IN-VITRO WHIPLASH SIMULATION

Knowledge of precise head kinematics during whiplash trauma is importa nt for identifying possible injury mechanisms and their prevention. Th is study reports a comprehensive data set describing head kinematic re sponse to horizontal accelerations simulating whiplash. Seven isolated fresh human cervical spine specimens (CO to T1 or C7), each carrying a surrogate head designed to represent a 50th percentile human head, w ere mounted on the sled and subjected to incremental trauma by horizon tal sled accelerations of 2.5, 4.5, 6.5, 8.5, and 10.5 g. Sled and hea d kinematics were measured with potentiometers and accelerometers. The incremental sled accelerations resulted in average (standard deviatio ns) sled velocity changes (Delta V) ranging from 5.8 (0.2) to 15.8 (0. 2) km/h. Generally, all the peak head kinematic parameters increased w ith increasing sled acceleration, except for the peak head angular dis placement, which decreased. In the initial phase of a whiplash trauma, the head translated posteriorly with respect to T1, without rotation. In the later phase, the head rotated backwards, but much less than it s physiological limit. Maximum head rotation of 31.5 (23.9) degrees oc curred in a 2.5 g trauma class, and this was less than the maximum phy siological head extension of 55.1 (13.3) degrees. Head kinematics expr essed in the TI or shoulder coordinate system is better suited to stud y potential neck injury in whiplash. (C) 1998 Elsevier Science Ltd. Al l rights reserved.