Motion Analysis of Human Cervical Vertebrae During Low-Speed Rear Impacts by the Simulated Sled

In an attempt to better understand the mechanism of motion of human cervical vertebrae during low speed impacts, the motion of the cervical vertebrae was analyzed using conditions such as the sitting position and the seat performance characteristics. A new impact sled was developed which simulated actual car impact acceleration. Ten volunteers participated in the experiment. Test speeds of 2, 4, and 6 km/h (.8, 1.6 and 3.2 mi/h) were selected. Two types of seat performance were used; a conventional car seat and a rigid wooden seat. Cineradiography recorded the motion of the cervical vertebrae at impact. The test results showed that a downward and rearward extension motion of C3 compared to C6 occurred and the cervical spine was compressed in an early stage of impact. Moreover, it was found that when the seat was rigid and speeds were increased, the ramping up motion of the body of the subject and neck compression were more typical. The vertebrae motion was analyzed and then compared with the differences between crash motion and normal motion. Based on this study, it is concluded that compressive vertical motion plays an important role in minor neck injuries.

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