Introduction to whiplash
Whiplash is a term that describes injury to the neck that occurs as a result of a motor vehicle or car accident. The most common type of car accident is the rear impact, and most typically, the occupant in the vehicle that gets "rear-ended" (hit from behind) is at the greatest risk of injury, including whiplash.
Until recently, the reason for the extent of whiplash injury was poorly understood. In addition, due to the legal and insurance issues, the veracity of complaints of neck pain and other symptoms by people who suffer from whiplash is commonly viewed as suspect.
However, recent research has helped clarify why occupants struck from behind experience more extensive whiplash injuries than those in other types of crashes. This new information is important for the physician treating these whiplash problems, as it impacts the physician’s case management strategy.
In fact, whiplash injuries can be quite complex and may include a variety of related problems, such as:
- Joint dysfunction
- Disc herniation
- Faulty movement patterns
- Chronic pain
- Cognitive and higher center dysfunction
How does whiplash occur?
When one motor vehicle strikes another from behind, certain forces are transmitted from the striking vehicle to the struck vehicle. These forces are then transmitted to the occupant(s) of the struck vehicle where they have the potential to cause whiplash injury.
Recent research, both in the Biomechanics Laboratory at Yale University in New Haven(1), and in live crash tests using human volunteers(2), has shed new light on the contortions the cervical spine (neck) undergoes as a result of impact and culminating in whiplash.
Shortly after impact (about 150 milliseconds), the cervical spine undergoes what is called an S-shaped curve. In this configuration, the cervical spine, rather than simply being curved to the front in a normal C-shape, as it would normally be at rest, takes on an altered shape:
- The lower part of the cervical spine moves into extension (bent backward)
- The upper part of the cervical spine moves into flexion (bent forward)
When this whiplash occurs, the lower part of the cervical spine moves well beyond its normal range of motion, causing the potential for injury to the ligaments and discs in that area. The upper part of the cervical spine also moves beyond its normal range of motion, but to a lesser extent.
There is an inherent stabilization response in the cervical spine that helps protect it from potential whiplash injury:
- The nervous system detects the presence of the impact; and
- The muscles of the cervical spine, under the direction of the nervous system, contract quickly to try to minimize the affects of the impact on the ligaments and discs.
If this stabilization response is working efficiently, there is a greater likelihood of protection against whiplash with less potential for whiplash injury. But if the response is inefficient, whiplash injury is more likely.
Factors affecting the whiplash injury
There are several factors that affect the efficiency of the stabilization response during whiplash, some of which are within our capacity to control, others of which are not. These include:
- Posture at impact
- Overall physical condition
- Awareness of coming impact
How posture at impact affects a whiplash injury
The posture in which a person is sitting at the moment of impact helps determine the efficiency of the stabilization response that will affect the severity of the whiplash injury. Sitting in a correct posture promotes an efficient stabilization response(3). Sitting in a poor posture, particularly a "slumped" type posture, promotes an inefficient stabilization response.
How overall physical condition affects a whiplash injury
The better conditioned the body is in general, the more efficient the stabilization response will be. This particularly relates to the condition of the nervous system, as a well-functioning nervous system is essential to a proper stabilization response.
How awareness of coming impact affects a whiplash injury
Perhaps the most important factor that affects the efficacy of the stabilization response in relation to whiplash is awareness of the impending impact.
Scenario 1: Aware of impending impact. This person is able to automatically prepare the stabilization system to respond quickly and efficiently.
Scenario 2: Unaware of the impending impact. This person cannot prepare the stabilization system, thus slowing the response and decreasing its efficiency. This person is likely to sustain greater whiplash injury than is the person who is aware.
This may help explain the findings of some studies(4, 5) that have shown a passenger in a struck vehicle is likely to sustain greater whiplash injury than the driver. The driver is more likely to see the vehicle coming in the rear view mirror.
How gender affects a whiplash injury
Women in general are more frequently and more seriously injured by whiplash than men due to the differences in muscular bulk and the female’s smaller bony structures. These factors result in less protection of the cervical spine to the abnormal forces such as those that occur in a whiplash-type of injury.
How other factors affect a whiplash injury
Risk factors influencing prognosis of a whiplash injury(6):
- Symptoms persisting beyond 6 months. (43% failed to recover on average)
- Significant ligament, disc, nerve, or joint capsule injury.
- Delay in initiating treatment
- Need to resume treatment for more than one flare-up of pain.
- Occupant age over 65
- Head restraint more than 2" away from occupant's head.
- Occupant in a small car
- Alcohol intoxication at time of automobile accident
- Pre-existing x-ray evidence of degenerative changes
- Prior whiplash injury
- Prior cervical spine fusion
- Patient having initial radicular (arm pain, numbness, tingling) symptoms
- A cervical collar used for more than 2 weeks
Common misconception about whiplash injury
A common misperception about whiplash injury is that if the vehicle does not sustain damage in a low speed impact, then whiplash injury to the occupant does not occur. In reality, however, low impact collisions can produce correspondingly higher dynamic loading on the occupants because the lack of crushing metal to absorb the forces results in a greater force applied to items or occupants within the vehicle(7, 8).
An important point to remember is if you have been in a motor vehicle accident, you usually won’t feel the threshold of your pain or discomfort until a week or two later. Do not make the mistake of judging the severity of your condition by your pain levels. Even in a low-force crash at speeds as low as 5 mph, individuals can be subjected to whiplash.
Chiropractic techniques and the chiropractor’s skill are particularly suited for correcting and relieving the otherwise debilitating effects of whiplash.
At Holmes Spine & Sport Chiropractic, we are dedicated to restoring your spine to good health by restoring joint movement lost after the accident and strengthening weakened muscles through chiropractic manipulation, massage and exercise rehab. It is possible to prevent chronic or reoccurring pain from injuries suffered during whiplash. The key is not to wait, but start your chiropractic care as soon as possible.
Hirsch SA, Hirsch PJ, Hiramoto H, "Whiplash Syndrome: Fact or Fiction?" Ortho C1 N Amer,19(4):791-95;1988.
- Panjabi MM, Cholewicki J, Nibu K, Grauer JN, Babat LB, Dvorak J. "Mechanism of whiplash injury." Clin Biomech 1998;13:239-249.
- Kaneoka K, Ono K, Inami S, Hayashi K. "Motion analysis of cervical vertebrae during whiplash loading." Spine 1999; 24(8):763-769.
- Murphy DR. " Normal function of the cervical spine II: Neurophysiology and stability." In: Murphy DR, ed. Conservative Management of Cervical Spine Syndromes. New York: McGraw-Hill, 1999:45-70.
- Harder S; Veilleux M; Suissa S. "The effect of socio-demographic and crash-related factors on the prognosis of whiplash." J Clin Epidemiol 1998 May;51(5):377-84.
- Parmar HV, Raymakers R. "Neck injuries from rear impact road traffic accidents: prognosis in persons seeking compensation." Injury 1993; 24:74-78.
- Nordhoff L: "Motor Vehicle Collision Injury for the 1990's Doctor/Attorney", Automotive Injury Research Institute,1994.
- Macnab I: "Acceleration Extension Injuries of the Cervical Spine." Rothman and Simeone, The Spine. 1982.