Whiplash is a relatively common injury that occurs to a person's neck following a sudden acceleration-deceleration force that causes unrestrained, rapid forward and backward movement of the head and neck, most commonly from motor vehicle accidents. The term "whiplash" was first used in 1928.
Fortunately, whiplash is typically not a life threatening injury, but it can lead to a prolonged period of partial disability. There are significant economic expenses related to whiplash that can reach 30 billion dollars a year in the United States, including:
- medical care
- disability
- sick leave
- lost productivity
- litigation
Whiplash is a real condition with often debilitating symptoms.
What causes whiplash?
Whiplash is most commonly caused by a motor vehicle accident in which the person is in a car that is not moving, and is struck by another vehicle from behind. It is commonly thought the rear impact causes the head and neck to be forced into hyperextended (backward) position as the seat pushes the person's torso forward - and the unrestrained head and neck fall backwards. After a short delay the head and neck then recover and are thrown into a hyperflexed (forward) position.
More recent studies investigating high-speed cameras and sophisticated crash dummies have determined that after the rear impact the lower cervical vertebrae (lower bones in the neck) are forced into a position of hyperextension while the upper cervical vertebrae (upper bones in the neck) are in a hyperflexed position. This leads to an abnormal S-shape in the cervical spine after the rear impact that is different from the normal motion. It is thought that this abnormal motion causes damage to the soft tissues that hold the cervical vertebrae together (ligaments, facet capsules, muscles).