When we hear the term “whiplash,” we
usually envision a rear-end motor vehicle collision that results in the head
being thrown to and fro, in a “crack-the-whip” manner resulting in a neck
injury. What we DON’T usually think about is “how to prevent whiplash,” which
is this month’s topic. Let’s take a look!
According to the “Whiplash
Prevention Campaign,” the most effective way to prevent whiplash injuries in
the event of a crash is to purchase a car with a highly-rated head rest and
then TO ADJUST THE HEAD RESTRAINT PROPERLY! Although airbags and seat belts
(and other safety devices and systems) help protect us in front and side impact
collision, a properly designed seat and adjusted head restraint will protect us
the most from sustaining a whiplash injury in a rear-end collision.
Here’s how it works! The most common
problem with head restraints is how they're positioned. In most cases, the head
restraint is placed too low and too far from the back of the head. In a
“typical” rear-end impact, the car and car seat are propelled forwards while
the unsupported head stays still resulting in a relative extension of the
cervical spine (neck). This “hyper-extension” is exaggerated by a seat that is
set in a semi-reclined angle, which causes a ramp-effect that allows the head
and neck to slide up and over the head restraint! Also, the “springiness” of
the seat back can further augment the forward propulsion of the body upon
impact and exaggerates the forward “bounce” of the body and head AFTER the
hyper-extension of the neck as the body is propelled forwards in the second
phase of the whiplash injury. A properly adjusted head restraint (and seat back
angle) does NOT allow the head to ride up and over the head rest thus
preventing injury in the initial phase of the rear-end collision.
To properly adjust your head
restraint, have another person assist you while you are properly sitting in the
seat. Once the restraint’s position is properly set, place a piece of tape
and/or a marker on the head restraint brackets/posts so if someone else drives
the vehicle and alters the position, you can easily return it to its proper
height FOR YOU! Note: 1) Do NOT recline the seat back greater than 20 degrees;
2) While sitting comfortably, have the other person slide the head restraint
upwards until the top of the restraint is EVEN WITH THE TOP OF YOUR HEAD; 3)
Move the head restraint forwards so that it is about 5 cm (2 inches) from the
back of the head because closer head restraints are two times more effective at
injury prevention vs. those set further back!
Unfortunately, a Canadian study in
2002 found that only about 14% of the headrests evaluated were properly
adjusted! In the United Kingdom, the percentage was a little better (28%), but
that means 72% of front seat occupants failed to properly adjust their head
restraints or they had head restraints that could NOT BE PROPERLY ADJUSTED! Of
the remaining 28% who did have the head restraint in the proper position, 11%
had a fixed / non-adjustable one piece design and the protection was limited to
only a shorter person!
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