Back Pain After Motor Vehicle Accidents
In addition to whiplash/neck injuries, the mid and lower back are also frequently injured in motor vehicle accidents (MVA's).
Mid Back Pain
The mid back or thoracic spine is most commonly injured as a result of the asymmetry of most seat belt designs. As the torso moves forward the seat belt locks and the torso is forced to stop at the end of the shoulder strap. Because the shoulder strap crosses only one shoulder (usually the left), the side without a strap (usually right) is able to travel forward further which results in a forward flexing and twisting injury to the mid back.
Lower Back Pain
The lumbar spine is also frequently injured, but the mechanism differs from the above. As the torso and pelvis move forward the pelvis is stopped by the lap belt. However, the torso continues to move forward which producing a shearing force in the lumbar spine. These injuries often result in lumbar disc injuries.
Back Pain Sources
Spinal injuries can damage a number of pain sensitive structures located in the spinal region. Some of the more common structures that are damaged and that have innervation which allows them to transmit pain include:
- anterior longitudinal ligament (runs down the front of the vertebral bodies-prevents excessive extension)
- outer layers of intervertebral disc (located between adjacent vertebrae)
- posterior longitudinal ligament (runs down the back of the vertebral bodies-prevents excessive flexion)
- nerve root dura
- capsule of the facet joints
- intervertebral ligaments
- extensor musculature
- flexor musculature: the colli and scalenes