Unlike the thoracic and lumbar areas, the cervical spine is much more vulnerable to injury during vehicle collision whether frontal, side, rear-end, or roll-over. At the time of vehicle collision, forces are transmitted to the restrained or unrestrained occupant. The head can be loaded by direct impact with surfaces in the occupant space or can exert inertia while being whipped around by various forces. The only structures stabilizing the neck are the muscles, the intervertebral disc and the configuration of the posterior apophyseal joints and their supporting ligaments. The most common modes of cervical spine injury are flexion, rotation, axial loading, shearing and extension.
Fracture dislocation of the cervical spine involves a high risk of injury to ,the spinal cord that can result in partial or complete quadriplegia. Cervical spine fracture at the highest level (C1-C2) with cord trauma is usually fatal.
Our accident research team has investigated various motor vehicle collisions in which occupants have sustained these potentially serious upper cervical spine fracture/dislocations. We discuss the reconstructed injury mechanisms, biomechanics and the implications for occupant protection.