What happens?
The term whiplash describes any indirect neck injury to the cervical spine, excluding fractures. The most common reason behind a whiplash injury is a rear-end collision between two cars. Rear-end collisions are related to more severe symptoms versus collisions from any other side. The severity of a whiplash injury depends on the magnitude of the differential velocity between the head and the upper torso. This difference in velocity causes the joint between the head and neck and the joints of the upper neck (cervical spine) to hyperextend (head jolts back) and then hyperflex (head whips forward). This trauma can lead to:
- Intense neck pain and stiffness
- Loss of range in motion in the neck
- Headaches that start in the base of the skull
- Tenderness in the shoulders, upper back or arms
- Tingling or numbness in the arms
If the velocity difference between the neck and upper torso can be reduced, the negative effects can also be minimized. Meaning, vehicle accidents at lower collision speeds can lower the adverse effects of whiplash. If a moving car hits your immobile car, you can still feel the effects of whiplash.
Risk Factors
Collision direction
Although any type of collision could lead to a whiplash injury, the odds are much higher when the impact comes from behind. A study investigated people in rear-end crashes are subject to more diverse neck movements upon the crash. They experience a rapid change in direction of the head within milliseconds. It should also be noted that rear-end collisions often result in the head striking the car chair head restraint, leading to more adverse effects.
Impact by greater masses
Generally speaking, the degree of whiplash injury increases as the relative difference in mass between the colliding vehicles increases. A vehicle with a larger mass will transfer more energy against a smaller vehicle, the occupants of the smaller vehicle are significantly at more risk to get injured.
Positioning of head restraint
The more effective and safe way to have the head restraint placed is at the center of gravity of the occupants head, approximately at the level of the top of the ears. A position lower than this will increase the risk in neck damage. The height of the occupant could increase the likelihood of whiplash, as the head restraint would be too low for taller people. Keeping this in mind, it’d be wise to have a head restraint capable of protecting the heads for all heights of passengers regularly in your vehicle.
