A sudden forced movement of the head or neck in any direction and the resulting “rebound” in the opposite direction is known as whiplash. The sudden “whipping” motion injures the surrounding and supporting tissues of the neck and head. Muscles react by tightening and contracting, creating muscle fatigue, which can result in pain and stiffness. Severe whiplash can also be associated with injury to the intervertebral joints, discs, ligaments, muscles, and nerve roots. Car accidents are the most common cause of whiplash.