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ROAD TRAFFIC ACCIDENTS
Road traffic accidents include the followings:
I. Injuries to pedestrians.
2. Injuries to pedal cyclists.
3. Injuries to motorcyclists.
4. Injuries to occupants of the vehicle.
INJURIES TO PEDESTRIANS
Usually the pedestrians who are at risk are young children and
elderly peoples.
The site and nature of pedestrian injuries depend on:
1. The height of pedestrian.
2. The height of the car.
3. The position of pedestrian in relation to the vehicle when struck,.
4. The feet of the pedestrian on the ground whether both fixed or one is
raised.
5. The site of impact in relation to the center of gravity.
6. The striking part of the vehicle whether the front or back..
7. The surface of the road and foot wear of the victim.
Pedestrian injuries may be classified as:
1. Impact injuries:
a. Primary impact injuries: The first part of the body struck by the
vehicle.
b. Secondary impact injuries: Other parts of the body struck by the
vehicle.
2. Secondary injuries: Injuries caused by the victim striking other
objects such as the ground. These injuries vary from abrasions,
contusions, lacerations, fractures, alone or in combination.
A. If the front of the vehicle struck the pedestrian from behind:
• The primary impact injuries will be on the back of the legs (calf)
• caused by the bumper of the car resulting in soft tissue injury and even
compound comminuted fracture of tibia (may be with the fibulae) in one
or both legs, this is called bumper fracture (the bumper is responsible for
femoral fractures in children).
• Secondary impact injuries: when the body is thrown backward, the•
buttocks and back comes in contact with the car causing injuries in the
form of bruises even fracture dislocation of thoracic and/or lumbar
vertebrae even may be fracture pelvis. At high speed the pedestrian may
be moved upward and slides onto the bonnet (hood) and sustains
secondary impact injuries of the head and shoulders as they come in
contact with the windshield .
• Alternatively the body may be thrown forward thus striking the ground
and causing secondary injuries in the face, palms and knees
B. if the front of the vehicle struck the pedestrian front the side:
- The primary impact injuries: will be against the side of the leg.
• Secondary impact injuries: will be in the side of the knee, thigh,
abdomen, chest and lateral aspect of the upper limb.
• The pedestrian is then pushed forward or to the side with resulting
secondary injuries on striking the ground. The injuries affect the head
(bruises, fractures of the tempro-parietal region even brain contusion),
lateral aspect of the shoulder, and upper part of thigh, buttocks and leg.
C. If the pedestrian is facing the front of the vehicle:
The pedestrian may sustain intra-abdominal injuries and/or injuries to the
chest wall and thoracic contents (heart, lungs). If the impact is against the
symphysis pubis, it leads to transverse fracture across the pubic rami
which may be accompanied by retroperitoneal hemorrhage and shock.
D. Crush, injury
When a pedestrian struck by a vehicle, he may fall to the ground and run
over by the wheels of the vehicle (this is common in children). The
following injuries may be present:
1. Impact abrasions (tyre marks) from tyres of the vehicle, contusions, or
lacerated wounds. ‘
2. Head: severe head injuries, lacerated scalp, skull fractures, brain
laceration.
3. Chest: fracture ribs, pleural tear, lung lacerations, heart contusion even
rupture, rupture of the aorta.
4. Abdomen: laceration and rupture of liver, spleen, tear of small and
Large intestines.
5. Limbs abrasions, contusions, lacerated wounds, fractures. Muscle
injury —> myoglobinuria —> acute tubular necrosis  Renal failure
(Crush syndrome).
E. Friction burn or brush abrasion:
Results from dragging of the pedestrian along the ground
INJURIES TO PEDAL CYCLIST
The injuries usually are mild, but occasionally serious injuries may occur
with fracture of bones, This is usually results from friction, between the
skin of the rider and the surface of the road.
When a bicycle is struck by a motor vehicle, the rider sustains both
primary impact injuries caused by the’ vehicle (usually in thighs and legs)
and secondary injuries from hitting the ground (usually head injury).
Bicycle spoke injury
This occurs when a child falls, from a bicycle and forces his foot and leg
in between the ‘spokes of the wheel. It is usually in the form of damage
of soft tissue of the calf.
INJURIES TO MOTOR CYCLISTS
The motor cycle may slide, or overturn and if at the time of contact with
the ground, the gas tank explodes, a combination of mechanical and
thermal injuries may occur.
Falling from the machine may cause injuries .in any part of the body
especially the extremities. The rider may be ejected leading to severe
head injuries. This is why the use of safety helmets is mandatory by law.
INJURIES TO OCCUPANTS OF THE VEHICLE
Mechanism of injury:
in unrestrained driver
On impact the lower half of the body is thrust forward and upward, thus
injuring the knees by the lower edge of the instrument panel . The whole
body then lifts and the head strikes the wind screen, while the abdomen
and chest may impact against the lower edge of the steering wheel.
In right front seat occupants = suicidal seat:
As there is no steering wheel, they are commonly thrown through the
wind screen, or they may come in contact which the dash board.
in back seat occupants:
As there is no wind screen or dash board, they may be thrown forward
striking the back of the front seat occupants, or they may strike the side or
top of the vehicle, even they may be ejected from the doors or windows.
Any type of injury can occur as abrasions, contusions, lacerations,
fractures, fracture dislocation, tear or rupture of organs.
injuries in driver and front seat occupant:
1. Head injury
It is caused by striking the wind screen or its frame, Superficial cuts in
the face and neck may occur from the flying glasses (now these injuries
are less common due to the use of laminated glass). Skull fractures and
brain injury in the form of concussion, contusions and intracranial
hemorrhage can occur.
2 Neck injury:
A type of injury occurs in rear impact called Whiplash injury. Where the
head is violently extended and then, violently flexed, this leads to severe
injuries to the neck which varies from sprains, to rupture of anterior
longitudinal ligament, even fracture dislocation of the cervical vertebrae
especially at the leyel of 5th and 6th cervical vertebrae or at the
at(antooccipital joint. The introduction of high back seats to support the
neck (antiwhiplash seats) minimized this type of injury. The front seat
occupant being unprepared, his head will strike against the windscreen or
its frame, and may even sustain a fracture dislocation of the cervical
vertebrae (whiplash injury).
2. Chest injury:
Chest injury resulting from . impact with the steering wheel Occurs
frequently in the driver. The visible external injury may be absent,
minimal or even gross. The imprint of the lower rim of the steering wheel
can be seen on the chest (Impact abrasion).
a. Sternum is depressed or. fractured, due to direct violence.
b. Rib fractures, may be tear in the pleura, laceration of the lungs (by end
of fractured ribs) leading to Pneumothorax or haemothorax.
c. Heart contusions on the anterior wall (coup) or on the posterior wall
(contrecoup), rupture of the heart or major blood vessels.
For prevention of this type of injury there are air bags and the collapsible
steering column.
In front seat occupant, there is no steering wheel, so chest injuries are less
severe and are due to striking the dash board.
3. Abdominal injuries:
In the form of contusions, lacerations, tears of the liver, spleen, kidney
and pancreas. Rupture of hollow organs as stomach, intestines, fracture of
pelvis, may be rupture of bladder and retroperitoneal hemorrhage.
4. Injuries of the Extremities:
A. Upper limbs:
The driver is usually aware that an accident will occur, so he put most of
his force on the steering wheel by his hands, thus avoiding full impact of
the chest and head against the steering wheel and wind screen. So, he
may sustain injuries in the form of sprains or fracture of wrists or
forearms. In the front seat occupant, if he is aware that an accident will
occur, he puts his hands on the dash board and gets similar injuries like
the driver.
B Lower limbs:
i. Knee injuries due to impact of the front of knees against the dash board
and its instrument panel.
ii. Leg injuries: if the driver is aware of the accident, he apply brakes, this
may lead to fracture of tibia and fibula and if the femur is adducted —
posterior dislocation of hip, if the femur is abducted —> fracture shaft
and neck of femur, may be fracture pelvic bone.
The front seat occupant may be aware of the impending accident and
apply brakes so he gets leg injuries similar to those of the driver, also
dash board injuries to the knees with fracture femur.
EJECTION CRASH INJURY
Ejection from a vehicle results ii? severe and multiple injuries to
occupants regardless of their• original positions in the car. Ejection is
largely dependent on whether the doors spring open at the time of the
crash. The head, chest and abdomen of the ejected occupants bear the
brunt of impact, rib fractures occur in two thirds of the ejected victims
SEAT BELT INJURIES
Seat belts are very important in preventing injuries resulting from vehicle
collisions, particularly those due to ejection of the car occupants. But seat
belts themselves may on occasion cause major injury. These injuries vary
with the type of seat belt in use.
The Lap belt for example, may produce injuries to the abdomen
(contusions, rupture of small or large intestines, mesenteric rupture, and
vascular injuries), pelvic injuries with bladder rupture, and lumbar spine
injury. Since the lap belt offers no support to the upper half of the body,
head, neck and chest injuries due to acute flexion of the body over the lap
occurs. The diagonal belt may cause contusion, fracture clavicle or
sternum and injury to the breast and pregnant uterus.