Mechanism of Injury


The term whiplash is used to describe symptoms that arise from the cervical spine that are associated with typically a road traffic accident. The perception is that it is an exaggeration of the normal extension and flexion of the cervical spine. However this is incorrect. The cervical spine undergoes a S shaped change in its positioning and it is related to the principles of inertia. When a rear impact occurs the occupants car will start to move forward and the person within the vehicle initially remains unchanged . however as the seat moves forward there is a forward motion that is applied to the thoraco-lumbar spine but the head and neck initially remains unmoved. As the thoracic spine moves forward the head and neck now lag behind the body and the head and neck as a result appear to accelerate and then catch up with the body as it the flexes forward with rapid deceleration. The diagrams below help to understand the basis through which a whiplash occurs.

Rear impact collisions are the commonest mechanism by which whiplash arises and the motion of the head and neck during such a collision is illustrated

Stage 1

 

Stage 2

pic2

 

Stage 3

pic3

 

Stage 4

pic4