Nearly one third of all motor vehicle accidents are rear end
collisions, and it is this type of accident that is responsible for most whiplash
injuries.
Biomechanics, the study of how mechanical forces affect living
organisms, is useful in explaining how even a "minor" rear end collision can
result in a serious injury.
The biomechanics of a common rear end collision can be understood as
a sequence of events happening, one following the other. Newton's First Law of Motion
states that, "An object remains at rest or in a state of motion in a straight line
unless it is acted upon by an outside force." To put this into practical terms, if
you are sitting in your car at a stop light ("at rest") and are then struck by
another vehicle from behind, ("acted upon by an outside force"), you will
immediately not be ("at rest ") anymore. In this common scenario of whiplash
type injuries, your car is propelled forward, and as you sit in your seat with your torso
supported by the car seat, it too goes forward. What doesn't go forward in that split
second is your head. It generally stays where it is, but relative to your torso, it
travels backward as your car travels forward. Have you ever had someone come from behind
you and push you between your shoulder blades, and felt your head go backwards? Whiplash
biomechanics are just like that, only much more severe.
Hyperextension, or the abrupt movement of the head backwards, usually
causes the most damage in a whiplash injury, since there are no anatomical restrictions to
the range of motion. As a result of this sudden forceful movement of the head backward,
numerous types of injuries can occur. Tearing of the front muscles and ligaments of the
neck is common. (Muscles move bones, and ligaments hold bones together.) Tearing of the
blood vessels in the throat area can also be seen as well as tearing of nerves in the
neck. Disc herniations are also possible, and fractures are also of great concern.
When the vehicle finally stops as a result of braking or hitting
another object, your body is propelled forward, sometimes hitting the steering wheel,
windshield, or airbag. If you are wearing a shoulder restraint, your head will fly
forward, with a twisting motion, resulting in hyperflexion of the neck.
The results of whiplash injuries are numerous.
In the following pages, I will list the most significant of them.