Engineers Simulate Whiplash Injury and Study Results

There's no doubt that the ligaments and joints in the neck are strained during a whiplash injury. The joints are pressed together, and they also slide back and forth. The ligaments are stretched to the straining point. The joints in the lower part of the neck take the biggest beating. The risk of injury is greatest as the speed of the neck movement increases.

These are the results of a study from Yale University School of Medicine. Engineers at the Biomechanics Research Lab studied the effects of whiplash forces on whole cervical spine specimens. Using six cadavers (human specimens saved for study), various impacts were placed on the neck. High-speed digital cameras were used to record the spinal motions during impact.

The researchers reported a maximum strain of 51 percent at the C5-C6 spinal level. The force was greater than the strength of the ligament, and injury occured. Rear-impact forces of 3.5 g or more caused damage to the joints. Joint sliding increased as the severity of the impact went up. Ligament strain at the next lower level (C6-C7) occurred at about 40 percent when the force was at 8 g.

This study supports the idea that neck pain after whiplash comes from joint and ligament strain. Compression of the joints in both the upper and lower neck takes place. This force is beyond what the normal joint can handle. A better understanding of how whiplash occurs will help us prevent such injuries and offer improved treatment when they do occur.



References: Adam M. Pearson, BA, et al. Facet Joint Kinematics and Injury Mechanisms during Simulated Whiplash. In Spine. February 15, 2004. Vol. 29. No. 4. Pp. 390-397.