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:
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.
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