The **headrest** is a passive safety device that protects the neck and cervical spine in the event of a sudden impact. For it to function correctly, it is crucial that it is properly adjusted. The top of the headrest should be at the same height as the top of the passenger's head, and the distance between the head and the headrest should not exceed four centimeters. If the headrest is poorly adjusted, the neck may suffer a **whiplash** during an accident, as it will not have the adequate support to prevent sudden movements.

Therefore, having the headrest poorly adjusted increases the risk of suffering a whiplash in a traffic accident.