is that all driving can be dangerous.More than 80 per cent of all car crashes occur at speeds less than 40
mph.Fatalities involving non-belted
occupants of cars have been recorded at as slow as 12 mph.That’s about the speed you’d be driving in a
parking lot.”Seat belt safety pamphlet,
(D) Y HS 802 152, distributed by the U.S. Department of Transportation,
National Highway Traffic Administration.
percent (50%) of people involved in forces produced by an 8 m.p.h. collision
with experience concussions.” White, A.A. M.D., and Ponjabi, M.M. PhD., Clinical
Biomechanics of the Spine, Lippincott, (1978), pg. 154.
inertia of the car that has been struck will depend not only on its weight but
also on factors that will allow it to roll easily; for example, slippery road
conditions, whether the breaks were on, and whether the car had automatic or
standard transmission.A car that is
moving slowly will accelerate more rapidly than one that is stationary.
of damage sustained by the car bears little relationship to the force
applied.To take an extreme example: if
the car was struck in concrete , the damage sustained might be very great but
the occupants would not be injured because the car could not move forward,
whereas, on ice [transmission in neutral, foot off the brake, wet pavement,
etc.], the damage to the car could be slight but the injuries might be severe
because of the rapid acceleration [of body parts] permitted.” MacNab, Ian, F.R.C.S.,
“Acceleration Extension Injuries of the Cervical Spine,” The Spine,
1982, Second Edition, Vol. 2, pg. 648, 647-660.
of damage to the automobile bears little relationship to the force applied to
the cervical spine of the occupants.The
acceleration of the occupant’s head depends on the force imparted, the moment
of inertia of the struck vehicle, and the amount of collapse or force
dissemination by the crumpling of the vehicle.The inertia of the struck vehicle is related to the weight and the
relative ease with which the vehicle rolls or moves forward.”Charles Carroll, M.D., Paul McAfee, M.D., Lee
Riley, Jr., M.D., “Objective Findings for Diagnosis of “Whiplash.” Journal
of Musculoskeletal Medicine, March, 1986, pp 57-74.
accident does not need to be severe in order to generate cervical trauma.Using the brakes when the light suddenly
turns red ad when the neck is too relaxed is enough to cause trauma.The neck may be projected backwards even
though not violently. The head, which
weighs five kilograms and is balanced over the cervical spine, being supported
by only two small articular surfaces no greater that a thumbnail, is also
thrown backwards pulling the cervical spine with it.In addition, a sudden reflex contraction of
the flexors on the neck occurs with a certain delay.
It is easy
to imagine that the joint injuries are not the same if during a collision, or
any other accident, the head is directed along the axis of the impact or if the
head is rotated or if the impact is directed laterally.In the final analysis, it is the result of
the injury which is important.”Robert
Maigne, M.D., Orthopedic Medicine: A New Approach to Vertebral Manipulations,
CC. Thomas, 1972, p. 196.
position of the head at the moment of collision influences the type of injury.
This is particularly true of the degree of rotation in relation to the
direction of the impact… the foramen are open equally when the head faces
forward but are narrowed on the side toward which the head is laterally flexed
or to which the head is turned.Not only
will the already narrowed foramen be compressed more, but the torque effect on
the facets, capsules, ad ligaments will be far more damaging.Rotating the head at the time of collision
increases the possibility of more serious injury.”Rene Cailliet, M.D., Neck and Arm Pain,
1972, Davis Company, p. 69.
Note:Whether or not the occupants’ head is turned
at the time of the collision, may be one mechanism explaining hoe serious
injury may result from low speed impact.The ability of the neck to expend (move backwards) is reduced by almost
50 per cent when the head is turned to either side.As a result, if an impact would occur (even
at low speed) when the occupants’ heads were turned, the neck would not be ale
to extend as far before overstretching and tearing of the capsules and
ligaments would begin, thereby producing more serious damage.
McLaughlin has shown that when a 3,500 lb. traveling at 10 m.p.h. strikes the
rear of another car it may transmit to this car a force of 25 tons.The person’s body [in the car that is struck]
continues to move forward while, [then head] being hinged at the neck, snaps
backward.The average head weighs about
8 lbs., and the cervical vertebrae are very delicate; the force that is pushing
the head backward is even greater than believed, since the base of the neck
acts as a fulcrum and the leverage is applied near the top of the head.Therefore, the head snaps back with the
equivalent of several TONS of force – without any support, since “the muscle
control of the neck is caught off guard.”The end result, is a momentary posterior subluxation of the various
joints with fleeting narrowing of the foramina, so that the nerve root is
caught in a pinchers between the superior and inferior facets.”Seletz, M.D., “Whiplash Injuries,” Journal
of the American Medical Association, (Nov. 29, 1953) pg. 1752.
words, if a car is hit from behind causing it to move at a speed of 18 k.p.h.
(10.8 m.p.h.) within 0.1 second there is a 50-percent probability of cerebral
contusion for the occupants.” White, A.A. M.D., and Panjabi, M.M. PhD., Clinical
Biomechanics of the Spine, Lippincott, (1978), pg.154.
may result from sudden acceleration and deceleration of motor-powered vehicle
even in the absence of crash accidents.The rapid acceleration of motor vehicles, which our present high-powered
engines permit, may cause a forceful hyperextension of the neck of an unsuspecting
deceleration of a moving vehicle, which the very effect power brakes make
possible, may avoid a crash accident, but the unprepared passenger may keep
going into the dash or the windshield, the back of the front seat or onto the
dash or the windshield, the back of the front seat or onto the floor as the
case may be.How many times have we seen
purses, boxes, suitcases, children and dogs thrown forward, to be stopped only
by contact with a stationary part of the car?”Ruth Jackson, M.D., The Cervical Syndrome, Fourth ed., 1977, C.C.
symptoms referable to the cervical spine may have occurred immediately
following an injury or the symptoms may have appeared a few hours, days or even
weeks after the injury.They may have
appeared suddenly or they may have come on gradually.”Jackson, Ruth, M.D., The Cervical Syndrome,
Cherles C. Thomas., Co., (1977), Pg. 160.
primary consideration, however, seems to be time, which allows the soft-tissue
lesions to heal.The patient may be
symptomatic for 2 or 3 days, months or years.”White, A.A. M.D., and Panjabi, M.M. PhD., Clinical Biomechanics of
the Spine, Lippincott, (1978), pg. 158