Injuries to the Cervical Spine Caused by a Distributed Frontal Load to the Chest

Unembalmed cadavers were exposed to −G_x acceleration while restrained by applying a frontal load to the chest. A pre-deployed non-venting production air cushion mounted on a non-collapsible horizontal steering column provided the distributed load. The sled deceleration pulse was determined from a series of Part 572 dummy runs in which the HIC, chest acceleration and knee loads were at but not in excess of the limits specified in the current FMVSS 208.

A total of six cadavers have been tested. In three of the runs, there were severe neck injuries of the type which have not been observed previously in belted tests. They include complete severance of the cord, complete avulsion of the odontoid process, atlanto-occipital separation with ring fracture. This study does not claim to establish the injury potential of air bags but uses the air bag to provide a uniform restraining load to the chest to investigate the mechanism of neck injuries. High neck loads were encountered in this rode of impact in which the head and neck kinematics were different from those of belted cadaveric subjects. Cadaveric and dummy neck loads were also different. The proposed neck fracture load is 6.2 kN (1,400 lb). This is the resultant neck load.