Whiplash

Whiplash is a relatively common injury that occurs to a person's neck following a sudden acceleration-deceleration force, most commonly from motor vehicle accidents. The term "whiplash" was first used in 1928. The term "railway spine" was used to describe a similar condition that was common in persons involved in train accidents prior to 1928. The term "whiplash injury" describes damage to both the bone structures and soft tissues, while "whiplash associated disorders" describes a more severe and chronic condition.

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, and
  
  
• litigation.

While most people involved in minor motor vehicle accidents recover quickly without any chronic symptoms, some continue to experience symptoms for years after the injury. This wide variation in symptoms after relatively minor injuries has led some to suggest that, in many cases, whiplash is not so much a real physiologic injury, but that symptoms are more created as a result of potential economic gain. Many clinical studies have investigated this issue. Unfortunately, while there will always be people willing to attempt to mislead the system for personal gain, nevertheless, whiplash is a real condition with real symptoms.

Whiplash is most commonly caused by a motor vehicle accident in which the car the person is riding in is not moving, and is struck from a vehicle from behind without notice. It is commonly thought the rear impact causes the head and neck to be forced into hyperextension 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 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).

Source: MedicineNet.com
http://www.medicinenet.com/whiplash/article.htm