This chapter summarizes the research on the biomechanical responses of the neck in a form that will be useful in design of protective systems and in the development of societal strategies to reduce the number of cervical spine injuries. Neck injuries are described in detail and injury mechanisms are explained. Accidents that involve neck injuries are analyzed. Real-life neck injuries are presented and laboratory results are synthesized to provide a rational basis for understanding neck injury. In order to maintain a reasonable scope, we restrict our discussion to severe fractures – those with a high probability of spinal cord injury. Low AIS injuries, such as whiplash, sprains and strains are left to other sources.
Most of what we know about catastrophic neck injury comes from two sources: clinical studies including accident reconstruction, and cadaver studies. In the last 30 years, the field of biomechanics has made significant gains in understanding the complex dynamics that accompany both head-impact neck injury and inertial neck injury. Cervical injury mechanisms involve a wide range of loading modes with various combinations of force and concurrent bending moment. Using the historical concepts of excessive head motion as a cause of neck injury frequently leads to paradoxical and incorrect conclusions regarding neck injury mechanism. In contrast, when the neck is viewed as a mechanical structure, whose injury is a consequence of the deformations of a segmented beam column bounded by two large masses, the neck’s mechanical behavior and the resulting traumatic injuries can be more readily explained. That is, by considering the effects of buckling and examining the forces and moments that act at the level of injury in the spine at the instant of injury, the mechanisms of each injury become clear and rational.