It has been claimed that 85% of the neck injuries caused by car accidents are the result of rear-end collisions. This type of injury is called a whiplash injury, and its mechanisms are not completely understood due to the limited ability to diagnose them using X-ray or MRI. Biomechanical studies including research on injury mechanisms, injury criteria, neck kinematics and injury epidemiology were reviewed to investigate the details of whiplash injuries. Many different injury mechanisms has been studied and identified such as hyperextension of the neck, facet joint impingement, spine column pressure, and muscle strains. Possible injury criterions have been reported as The Neck Injury Criterion (NIC), Nij criterion, IV-NIC criterio, Nkm criterion, NDC criterion.