2. Agenda
1. Introduction
2. Risks factors of traffic accident
3. The dynamics of vehicular injury
4. Pattern of injury of vehicle occupants
5. Cause of death in traffic accidents
6. Injuries to pedestrians
7. The effect of seatbelts
8. The vulnerability of children in vehicles
9. Injuries to motorcyclists
10. Injuries to pedal cyclists.
11. Railway injuries
12. Aircraft disasters.
13. Ferryboat accidents
3. Transportation accidence: are occurrence of sequence of events
which usually produces unintentional injuries or death during
transportation.
Transportation trauma: is a complex of mechanical lesions
produced by the external or internal parts of a moving transport unit,
just as the fall from it.
1- 3,400 people die on the world's roads / day. one death / 26.3 second
2- 20-50 million are injured or disabled every year. 15 injuries/second
3- Children, pedestrians, cyclists and the elderly are the most.
4- Males aged 15-44 years the most exposed to road traffic injuries.
5- The 2nd leading cause of premature death (behind HIV/AIDS) worldwide.
6- 11th leading cause of death globally.
7- Responsible for 2.2% of annual global deaths.
http://www.cdc.gov/ncipc/pub- res/research_agenda/06_transportation.htm
World Health organizationReport 2004.
4. Public transportation "common carriers."
Taxis
Bus
Trains
Plane
Ferries
Trolleys
Elevators
Escalators المتحركة السللم
Movable walkways
Airport shuttles
- Light vehicles: cars and light vans under 1.5
tonnes
- Heavier vehicles: trucks and buses.
5. I. Terrestrial:
•Wheeled:
a) rubber (cars, buses, motorcycles, trucks, tractors, etc.)
b) Metal (train, tram);
•Without wheels:
a) caterpillar (tractors, armored)
b) without caterpillars or wheels (escalators etc.).
II. Underground: (the same as terrestrial)
III. Aviation:
•Propeller (aircraft, helicopter);
•The jet engine (airplane);
•Without motor (flying-plane).
IV. Naval:
•Aquatics
•Underwater
Classification of transport units
6. Risks factors of traffic accident :
Injured person
Psychological factors: lack of experience, risk taking, defective judgment, delay in
decision making, poor perception, family dysfunction.
Medical factors: sudden illness, heart attack, impaired vision, hearing and fatigue,
alcohol, myocardial infarction, diabetic coma or drug intoxication.
Failure to follow regulations
Aggressive driving behaviors: reckless driving
Cell-phones
Driver negligence
Seat-belts and child restraints not used
Vehicle
Defective equipment
Improper maintenance
Inadequate safety measures
Environment:
Weather conditions
Dangerous roadways
7. In transportation- related death , the postmortem
examination is performed
1- To establish the identity of the deceased (especially in burned,
charred or mutilated body)
2- To determine the actual cause of death and whether or not death
was due to the vehicular mishap,
3- To determine the extent of injury, any contributing or precipitating
factor(s).
4- To document findings for possible use in criminal or civil
proceedings which may follow
9. a)specific to a concrete type of trauma
b)characteristic (depend on the mechanism of a concrete type of trauma)
c)uncharacteristic (may be in all conditions of mechanical trauma)
d)simulated (they look far from blunt trauma)
Classification of transportation
injuries
Classification of car trauma
Trauma due to automobile collision with pedestrian
•Trauma by crossing with car wheels
•Trauma in the interior of the car
•Trauma due to falling from car
•Trauma by compression between car parts and other objects or obstacles
•Combined trauma
10. 1- Tissue injury is caused by a change of rate of the movement. A
constant speed, however rapid, has no traumatic effects. The
traumatic injuries occur always in acceleration and deceleration
2- Change of rate measured in 'gravities' or 'G forces'. The amount
that a human body can tolerate depends greatly on the force direction
and it depends upon the force applied per unit. Formula: G =
C(V2)/ D where,
V is velocity in km/hour,
D is the stopping distance in meters
after impact
C is a constant 0.0039.
3- Between 60 - 80 % of vehicular crashes are frontal, 6 % are rear
impacts, 0.5 % are sideswipes and the rest 'roll-overs'. (knight,
1996).
4- The pattern of injury varies according to occupant position.
5- Heavy goods vehicles suffer less than cars and light vans because
The dynamics of vehicular injury
11. The driver in front impact
1- The unrestrained driver first slides
forwards so his legs strike the parcel-shelf
area.
2- The abdomen or lower chest contacts the
lower edge of the steering wheel.
3- The body then flexes across the steering
wheel and begins to rise.
4-The heavy head goes forwards, and there
is flexion of the cervical and thoracic spines.
5-The upward and forward component
causes the head to strike the windscreen, the
upper windscreen rim or the side pillar
6-The windscreen is often perforated by the
head or face, and the whole body may be
ejected through the broken glass, to land on
the roadway ahead.
Major points of injury to an
unrestrained driver of a vehicle in
deceleration impact
12. Pattern of injury of vehicle occupants:
1- Be ejected through the broken glass to the land.
2- Intrusion of structural parts into the passenger compartment.
3- The engine or front-wheel assembly may be forced back into the
seating area, intruding upon the driver.
4- The roof (the so-called 'A'-frame) may cave in on top of the
driver.
5- One effect of column, engine, or gearbox intrusion may be to force
the floor up and backwards against the driver's feet and legs.
6- The control pedals intrusion, and the reflex pressure of feet on
rising pedals and floor may cause transmitted force up the legs and
into the pelvic girdle.
7- The steering column is a more dangerous item for intrusion, being
forced back to 'stab' or crush the driver's chest or abdomen. the
wheel itself breaking and penetrating the chest.
8- The door may burst open and the driver may ejected sideways
13. Transportation injuries
1-Bruising, laceration and bilateral leg fractures of a car driver in a frontal impact.
2- Severe internal injuries. Laceration of the skin is rare unless the steering wheel
snaps and penetrates the trunk.
3-Other steering-wheel lesions include bruising of the lungs, fractured ribs and
sternum, cardiac contusion and haemothorax or pneumothorax or both.
4- Upper limb injuries are less common but may occur from transmitted force
through gripping the steering wheel or from impact against the windscreen when held
up in a reflex protective position.
15. Head Injuries
1- Abrasions and bruises: Bruises may shift downwards causing a “black eye”
2- Lacerations: impact strikes the skull by the windscreen. Avulsion of a large
area of scalp, can be torn from the head, thereby exposing the aponeurosis or
skull where a rotating vehicle tyre comes into contact with the head, causing a
'flaying injury.
3- Facial injuries: Lacerations of the prominent parts (e.g. forehead, eye-brow,
nose, chin)
-Black eye may occur due to either: direct trauma to the eyes or indirectly
by:
Gravitation of blood from higher levels in the body
Percolation of blood in case of fracture base of skull (ant. Cranial fossa)
1- Windshield and side window glass cause characteristic injuries. A
windshield is composed of two pieces of glass bonded together with plastic.
2- Side windows are made of tempered glass which shatters during impact
into numerous small fragments. These fragments cause a characteristic
"dicing" pattern of lacerated-abrasions on the face, shoulders, or arms.
3- Observation of this pattern is one method of determining an occupant's
position. A driver has dicing injuries on the left side of his body and a
passenger has them on the right.
16. 4- The face‘ frequently suffers multiple cuts from contact with the
shattered safety glass. In most European vehicles the glass is of the
toughened, not laminated, variety and, when broken, it shatters into
small cubes with relatively blunt edges. These still cause superficial
lacerations, often in short 'V-shaped' or 'sparrow-foot' patterns.
5- Hyperflexion of the cervical spine when the head swings can cause
fractures or dislocation. The atlanto-occipital dislocation,
- Other fractures can occur anywhere in the cervical spine, often at
about C5-6. dorsal spine, often around T5-6-7.
6- Skull Fractures: Three main factors affect the type of skull fracture:
Severity of the force
Size of the striking surface
Movement of the skull
Comminuted fracture : More common with wider impact to skull,
accompanied by tearing of vessels and/or brain lacerations
Hinge fracture : Affects base of skull separating it into two halves . May
associated with brain stem into the foramen magnum herniation
17. 7- Subdural bleeding:
Arises from shear stresses in the upper layers of the cerebrum, which moves
the communicating veins laterally sufficiently to rupture their junctions at
either the cortical veins or the sinus surfaces. Subdural bleeding is most often
over the lateral surface of a cerebral
hemisphere, high up in the parasagittal area.
- As with most intracranial damage, cause is
a change of velocity of the head, either
acceleration or deceleration, almost
always with a rotational component.
- Where a blunt impact strikes the skull, the subdural bleed need not be
situated directly under the impact area - it need not even be on the same
side of the head. It is sometimes tempting to attribute a localized subdural to
either a 'coup‘ or to a 'contrecoup' effect
18. 8-Concussion
An injury to the head causes the brain to
bounce against the rigid bone of the skull.
This force may cause a tearing or twisting
of the structures and blood vessels of the
brain, which results in a breakdown of the
normal flow of messages within the brain.
Less damage nerves can repair themselves.
More severely damaged nerves lead to
swelling and disintegration of the nerve.
Grade 1
The mild concussion occurs when the person does not lose
consciousness (pass out) but may seem dazed.
Grade 2
The slightly more severe form occurs when the person does not lose
consciousness but has a period of confusion and does not recall the
event.
Grade 3
The classic concussion, which is the most severe form, occurs when the
person loses consciousness for a brief period of time and has no
memory of the event.
19. Forensic anatomy
- The two vertebral arteries arise from each subclavian
behind the sternoclavicular joints.
- Each artery ascends behind the common carotid to
reach the transverse process of the 6th
cervical vertebra.
-Then enter the foramen in that process and passes
upwards through each similar foramen until it emerges
from the upper edge of the second (axis) vertebrae.
-Then bends laterally and enters the final foramen in the
atlas vertebrae.
-Penetrates the posterolateral aspect of the atlanto-
occipital membrane and the underlying spinal dura and
arachnoid, emerging on the lateral side of the spinal
canal just below the foramen magnum.
- Both arteries then ascend and converge on the ventral
surface of the medulla and pons to fuse in the midline to
become the basilar artery.
Spinal cord ends with a bulb like structure
(conus medullaris) between L1 & L2
Cauda equina (Bundle of nerver fibers) starts at
L1-L2 level
20. In a rear impact
1- The driver is violently
accelerated and, if no rigid
head restraint is fitted to the
seat, severe hyperextension of
the neck occurs, often
followed by the sequence of
deceleration events when the
car is cannoned into the
vehicle or other obstruction in
front, causing the 'whiplash'.
injury
2- Definition :
Whiplash is an acute injury caused by a strain to the bones,
muscles, nerves, tendons, and vertebral discs of the neck region
results from a sudden, unexpected impact which jerks the head back
and then forward causing the neck to snap out of alignment.
22. 2- Bilateral Facet Dislocation
Flexion injury
Subluxation of dislocated
vertebra of greater than ½
the AP diameter of the
vertebral body below it
High incidence of spinal
cord injury
23. crushed
All four phases of a whiplash injury occur in less than 1/2 second!
Phase 1 : During this first phase, the car
begins to be pushed out from under the
driver, causing his mid-back to be
flattened against the back of his seat.
This results in an upward force in his
cervical spine, compressing his discs and
joints.
As the seat back begins to accelerate the
driver's torso forward, his head moves
backward, creating a shearing force in
his neck.
-If the head restraint is properly
adjusted, the distance that the head
travels backward is limited. However,
head restraints only reduce the risk of
injury by 11-20%.
24. Phase
2
The driver's torso has reached peak acceleration - 1.5 to 2
times that of the vehicle - but his head has not yet begun to
accelerate forward and continues to move rearward.
An abnormal S-curve develops in cervical spine as the seat
back recoils forward, much like a springboard, adding to the
forward acceleration of the torso.
Unfortunately, this forward seat back recoil occurs while the
head is still moving backward, resulting in a shearing force in
the neck that is one of the more damaging aspects of a whiplash
injury.
Many of the bone, joint, nerve, disc and TMJ injuries that occur
during this phase.
25. Phase 3
Driver's torso is now descending back down in the seat and the
head and neck are at their peak forward acceleration.
At the same time, the car is slowing down. If the driver released
the pressure on the brake pedal during the first phases of the
collision, it will likely be reapplied during this phase.
Reapplication of the brake causes your car to slow down even
quicker and increases the severity of the flexion injury of your
neck.
As moving forward in the seat, any slack in the seat belt and
shoulder harness is taken up.
26. Phase
4 This is the most damaging phase of the whiplash phenomenon.
The torso is stopped by the seat belt and shoulder restraint and
the head is free to move forward unimpeded.
This results in a violent forward-bending motion of neck the,
straining the muscles and ligaments, tearing fibers in the spinal
discs, and forcing vertebrae out of their normal position.
The spinal cord and nerve roots get stretched and irritated, and
the brain can strike the inside of the skull causing a mild to
moderate brain injury.
If the driver are not properly restrained by the seat harness, he
may suffer a concussion, or more severe brain injury, from striking
the steering wheel or windshield.
27. Whiplash trauma
About 12% of persons who suffer from whiplash are symptom-free
after 10 years of the accident.
Neck Pain and stiffness
Headaches/migraines
Temporo-Mandibular Joint (TMJ) problems
Brain Injury
Dizziness
Low back pains and hip pain,
Nausea/vomiting
Problems thinking or remembering
Numbness and tingling (arms, face, shoulders)
Impaired vision
28. Common sites
for fracture
C7-T1 junction
T12-L1 junction
SCIWORA
Spinal cord injury without radiological
abnormality
Common in children
Spinal Injuries
Spinal Column
Injuries
Injuries to Neural Structures
(spinal cord, nerve roots)±
29.
30. 3.Cervical Fracture
- Cervical fractures usually result from high-energy trauma, such as
automobile crashes or falls.
- Any injury to the cervical vertebrae can
have serious consequences because the
larger percentage of the spinal nerves run
through the center of the vertebrae
-Injury to the spinal cord at the level of
the cervical spine can lead to temporary
or permanent quadriplegia, paralyzing
the entire body from the neck down.
4. Axial Loading
When the neck is slightly flexed (30°), the vertebra line up in a linear
(straight) fashion. Under this alignment, the force is absorbed entirely
by the bones ligaments and disks, rather than the muscles. This is
called axial loading.
Axial loading is now recognized as the primary cause of injury
although flexion-rotation, hyper-flexion, or extension may produce
significant injuries.
31. 5-Compression
Fracture Injuries may occur at speeds as low as 8-9 miles / h.
Most common injuries at C4-C6 but higher in older individuals
6- Neurogenic Shock
Temporary loss of autonomic function of the cord at the level of
injury results from cervical or high thoracic injury
Presentation
Flaccid paralysis distal to injury site
Loss of autonomic function
hypotension
vasodilatation
loss of bladder and bowel control
loss of thermoregulation
warm, pink, dry below injury site
Bradycardia
33. Chest Injuries
1. Injuries to chest wall.
2. Heomorrhage and
infection in the chest.
3. Pneoumothorax (types-
causes-complications)
4. Injuries to the lung
1. Injuries to the heart.
2. Hemopericardium and
cardiac tamponade.
3. Injuries to great vessels.
35. Injuries to the lung
1. Bruising of the lung: In open and closed chest injuries.
Site : Occurs at area of impact or contrecoup.
Deceleration injuries: Posterolateral surfaces “vertical
line of subpleural bruising” in the paravertebral gutter.
Rib imprints.
If severe contusion : Subpleural blood blisters, rupture
to release blood or air into the pleural cavities.
2. Laceration of the lung: “ as in blunt injuries.”
Lobes or parts of a lobe may be detached.
The hilum may tear." hemorhage into pulmonary
ligament” Vessels in the hilum may be ripped.”pulmonar
veins”
36. Injuries to the lung cont.
3. Penetrating injuries of the lungs : commonly results from the
steering column that introduced, and being forced back to 'stab'
or crush the driver's chest or abdomen.
4. Blast injury: the lungs are the most vulnerable organs to this
type of injury due to the large tissue-air interface.
5. Sternal and rib fractures : Other chest injuries due to impact
with the steering wheel, ejection through the windscreen or
impact with the road.
-There may be bruising or laceration on the chest from the
steering wheel, though padding, collapsible columns.
Beneath the skin, sternal and rib fractures ± flail chest are
common, though fatal visceral injuries can occur without rib
fractures in young people because their ribs are more pliable.
37. 6-Fractures of ribs
Fractures of ribs are common, but do not greatly restrict
respiration unless:
1. They are so numerous that they prevent expansion of the thorax.
2. Broken ends penetrate the pleura and lungs.
3. Pleural and muscular pain limit respiratory effort.
7- Flail chest
The condition of flail chest presents with multiple fractures of
some ribs ± fracture(s) of the sternum.
The loose section is sucked inwards during inspiration, this
clinical sign being known as “paradoxical respiration”.
Extreme degrees of flail chest are rapidly incompatible with life
because of progressive hypoxia.
Always caused by frontal violence, as in motor vehicle accidents “
where the victim is thrown against the steering wheel.
38. 8 - Heomorrhage in the chest:
Cause: ” Any injury to the chest wall or lung surface that reaches
blood vessels and the pleural lining”
Source : ” Intercostal, mammary arteries can bleed into the pleural
cavities, large vessels in the lung or mediastinum → causes massive
hemorrhage (the heart is also a source. )”
Complications : ”fatal hemorrhage, Cardiac tamponade, hemothorax
There may be air bullae or blood blisters under the pleura overlying
the bruised areas and a pneumothorax or haemothorax may result.
The interior of the lung may be pulped even in the presence of an
intact visceral pleura, from transmitted force or massive variations in
intra-thoracic pressure during the impact.
The lung often shows areas of bleeding under the pleura, which may
be from direct contusion, from aspiration of blood from other damaged
areas of lung or from blood sucked down the air passages from
injuries in the nose or mouth.
39. 9- Pneumothorax
1. Simple type: where a leakage through the parietal pleura
allows air to enter the pleural cavity, but the
communication rapidly closes →The lung partly collapses,
then the air absorbed.
If the communication remains open, a bronchopleural
fistula results “air is present in the pleural cavity but is not
under pressure”.
2. Tension pneumothorax : the leak in the pleura has a valve-
like action, air is sucked into the pleural cavity at
inspiration, kept trapped on expiration. Causes lung
collapse and mediastinal shift.
41. Injuries to the heart
1- The heart is vulnerable to both penetrating and blunt injuries.
2- The frontal surface of the heart is more commonly injured; but
also injuries to the post surf .heart are not uncommon.
3- Ruptured aorta a more common injury associated with
deceleration. It may be associated with a severe whiplash effect
on the thoracic spine, as the aorta is tethered to the anterior
surface of the vertebrae where the distal arch joins the straight
descending segment.
4- The most common reason for aortic rupture, is the 'pendulum‘
effect of the heart within the relatively pliable thoracic contents.
5- When the thorax is violently decelerated, the heavy cardiac mass
attempts to keep moving ahead and may literally pull itself off its
basal mountings.
42. 6- Separation takes place at the point where the aorta is attached
to the spine at the termination of the arch. Clean-cut circular
break, almost as sharp
7- ‘Ladder tears', a transverse intimal tears adjacent to the main
aortic rupture.
8- The cardiac injuries are usually on the front of the organ, to the
right ventricle.
9- Posterior bruising and laceration “heart is compressed against
the thoracic spine”.
10- All degrees of damage can occur, from mere epicardial bruising
to lacerations.
11-Completely avulsed from its base in high-speed impacts.
12-Subendocardial haemorrhages on the left side of the
interventricular septum is NOT a sign of impact, but an index of
catastrophic hypotension.
43. Abdominal Injuries
Liver
1- Ruptured liver : The major abdominal injury may be damaged in any part.
2- Central tearing : A common lesion of the upper surface, which may extend
deeply and even transect the organ.
3- Less serious damage : shallow, sometimes multiple, parallel tears on the
upper surface of the right lobe.
4- Subcapsular tears with the formation of a subcapsular haematoma,
which can rupture later.
Spleen
5- Shallow tears : in some accidents, often around the hilum;
Avulsed from the pedicle.: in rare cases,
6- Mesentery and omentum often show bruising and, rarely, there is
laceration and fenestration sufficient to cause a lethal haemorrhage.
7- Almost any kind of injury, usually multiple, may be sustained after
ejection, either from contact with the road surface or (in a significant
proportion) from being struck by other vehicles, especially on motorways.
44. The front-seat passenger:
The pattern of injuries is similar to that of the driver, but this position in
the car is even more dangerous,
1- There is no steering wheel to impact into the chest, its absence also
denies the slight protection offered to the driver in reducing the collision
with the windscreen, perhaps by giving him something to brace against
2- the driver gives his attention constantly to the road and so has
momentary warning of an impending crash, compared with the
passenger
Rear-seat occupants:
During violent deceleration, unrestrained occupants in the rear are
projected forwards and strike the back of the front seats, including
head-rests where fitted. They may be thrown over the seats, striking and
adding further injuries to the front seat occupants and may even be
ejected through the windscreen, which is broken by them or by the
people in front.
Ejection is another common cause of death and serious injury in rear-
seat occupants, a wide range of head, chest and limb injuries being
seen.
45. THE EFFECT OF SEATBELTS
(a) Simple lap-strap (dangerous to aorta),
(b) Diagonal only (can slip underneath),
(c) Diagonal plus lap-strap (usual car type),
(d) Shoulder harness used in aircraft & racing cars).
Various forms of strap restraints
act by:
A)Holding the occupant back against
the seat, so that forward projection
against the steering wheel and
windscreen is prevented.
B)The belt restrains the occupants
within the vehicle in the event of a door
bursting.
C)Extending the deceleration time and
distance by substantial stretching of the
belt
D) Spreading the area of application of
deceleration forces. The same
deceleration diffused against the thorax
and abdomen rather than against the
skull,
** Seatbelt-use reduces deaths and serious
injury by a factor of 20-25% in Australia New
South Wales and Britain.
46. 1-Pregnant women with possibility of uterine and fetal injuries
2- Too small persons(child or a small woman), may slide
from under the strap (‘ submarining )or it acts around the neck.
Below age 14 must be in rear seats in some European laws
3- Loose straps allow the body to move relative to the belt before sudden restraint
occurs, decreasing the distance between the passenger and facing structures.
4- Some women find that the diagonal strap compresses the breast, so that the
greatly increased tension during deceleration is likely to injure the gland.
5- Incorrectly adjusted or positioned straps such as a twisted belt, which reduces
the area of contact, can increase the danger of injury.
6- Bruising is the most common and may be seen either under the diagonal or the
transverse component of the three point belt.
7- It is more common with the single aircraft-type lap-strap because of the smaller
area of pressure.
Seatbelt injuries
47. 8- Bruising to the abdominal or chest wall, but the dangerous lesions are to visceral.
9- Rupture of the mesentery, or he small or large intestine, usually occurs from acute
flexion over a lap-strap.
10- The full bladder can be ruptured as can the caecum.
11- The abdominal aorta can be crushed and the lumbar spine suffer a compression
fracture or be dislocated through a disc in the midlumbar region.
12- The posterior arch, pedicles or transverse processes may also be damaged.
13-The diagonal strap usually prevents serious abdominal injury as it prevents
hyperflexion, but it may contribute to thoracic injury.
14- Bruising of the skin and underlying muscles and fractures may accompany a broken
clavicle or sternum where the belt crosses them.
Seatbelt injuries cont.
48. Airbags
1- A large fabric bag, folded into the steering- -wheel hub in the case of the driver
position and into the fascia in front of the front-seat passenger.
2- A sensitive deceleration device triggers the ignition of sodium azide, a solid and
highly toxic explosive propellant, which is converted in milliseconds to nitrogen gas.
3- The deploying airbag can reach speeds up to over 300 km/h (>200 mph). Deflation
is also rapid, so that residual car control and escape from the vehicle is not impeded.
4- The inflated bag is designed to interpose itself between the occupant and the frontal
structures to cushion the impact and prevent forceful contact and hyperflexion.
5- Injuries can be inflected at any stage, depending on the posture and possible objects
between the occupant and the deploying airbag or the module cover.
6- They vary from facial bruising, partial or complete amputation of fingers to
dislocated and fractured arms or cervical spine and fatal head injuries.
7- Eye injuries are common and range from mild corneal abrasions and chemical
burns from contact with unburned sodium azide or the alkaline byproducts of
combustion, to globe rupture from blunt trauma or perforation by interposed objects.
51. Mechanisms of production the lesions:
a)vehicle collision with pedestrians
b)fall the body on the car
c)fall the body on the road
d)sliding on the surface of the roadway
A- Automobile collision with pedestrian
May by:
•Complete
•Incomplete (transversal, longitudinal and oblique)
Mechanisms of production the lesions:
1)hitting the body by the wheel
2)pushing the body by the wheel
3)climbing wheel on body
4)crossing the body by wheel
B- Crossing with car wheels
52. C- Trauma due to falling from car
There are three kind of falling from car
a) anterior fall
b) posterior fall
c) lateral fall
Mechanisms of production the lesions:
1) Hit the body by the car parts
2) Fall on the road
3) Sliding on the road
D- Compression between car and other objects
Mechanisms of production the lesions:
1)hitting the body by the car
2)compression the body between the car and objects (obstacles)
53. Risk Factors For Pedestrian Collision
1- Two primary factors are when and where pedestrian collisions occur.
Most fatalities occur between the hours of 6 pm and midnight.
2- Impaired vision among drivers due to the lack of daylight, coupled with
pedestrian traffic and alcohol consumption by either the driver or the
pedestrian
3- Two-thirds of pedestrian fatalities occur in urban areas and three-fourths
occur in non-intersections.
4- Urban areas have a higher rate of pedestrian and motor vehicle traffic.
Drivers non-compliant with speed limitations, pedestrian lack of safety
awareness, poor city planning and other
Rural areas pose their own unique, significant risks. Although the overall
number of collisions is fewer than in urban centers, pedestrian injuries are
more severe and are fatal a greater percentage of times in rural settings
Higher vehicle speeds, lack of proper pedestrian walkways and larger
distances to a trauma center likely contribute to a higher mortality rate.
54. Why? Young Children:
Think that if they can see a driver, the driver can see them.
They think that cars can stop instantly
They can’t tell where sounds come from
They can’t judge how fast traffic is moving.
They have a field of vision 1/3 that of adults
They don’t recognize danger or react to it
They think of cars as friendly, living creatures
They are also more prone to be run over vehicle
and trucks, as they often play between parked
vehicles and - being small - are less visible to the driver.
The most common injuries seen in pediatric are traumatic brain injuries
and musculoskeletal injuries, the upper and lower legs and knees followed
by chest and abdominal injuries. Head injuries are generally more life
threatening.
Children have a lower center of gravity than adults and their shorter height
and smaller weight affects the mechanics of impact. The primary contact is
higher up their body, so they tend to be hit forwards rather than rotated
upwards, tend to be propelled to the ground even at lower speeds and are
often run over resulting in many points of impact and various injuries. Often
clothing and tissues can adhere to the undercarriage of a vehicle.
55. Pattern of Pedestrian injuries.
1- The points of impact on a body are important and clothing must
be examined for paint chips and parts of the vehicle that may be
transferred on impact.
2- Bumper impact sites on the legs should be measured from the
heel. The height will correlate with the height of the bumper.
3- A bumper fracture is often triangular in shape, the apex pointing
to the direction that a vehicle was moving. When the brakes are
applied, a bumper fracture occurs low because the front end of the
car drops.
4- When hit by a car, an adult pedestrian will be lifted up and may
strike the windshield or roof or be thrown over the car. Most
injuries arising from these vehicle and ground impacts to the head,
legs and pelvis., tibial plateau fractures and ligamentous injuries of
the knee, and traumatic brain injuries.
56. 5- Most pedestrians are struck by motor cars or trucks- during
an acceleration NOT during deceleration process.
6- Primary injuries are caused by the first impact of the vehicle
on the victim, while secondary injuries are caused by
subsequent contact with the ground. 'tertiary injuries' describe
the impact with the ground, reserving 'secondary' for additional
contact with the vehicle, as when the pedestrian is hurled up
against the windscreen.
7- A further hazard is being run over by the vehicle if the victim
is projected directly in front. Sometimes he may be dragged by
the under-belly of the car, and seriously soiled and injured,
8- Many impacts are on the front corner of the car and the
pedestrian may then be knocked diagonally out of the path of
the car.
9- If thrown into the centre of the roadway, the person can be
run down by a different vehicle overtaking in another lane or by
one coming in the opposite direction on a single carriageway.
57. 10- If scooped up, the victim will land on
either the bonnet or against the windscreen
or corner-supporting pillar (the 'A' frame).
11- The flat bonnet usually does relatively little
damage, though linear abrasions, brush
grazes, or friction burns may be seen. Violent
contact with the windscreen, especially the rim
or side pillars, is the most frequent cause of
severe head injury from primary impact.
12- Scooping-up can occur at speeds as low
as 23 km/hour the body will usually be
projected forwards.
13- If the speed is high, the victim can be
thrown up onto the car roof, sometimes
somersaulting so that the head strikes the
roof. He can then slide or be flung right over
the back of the car, landing- behind it in the
roadway. This is more likely to happen if the
car does not brake.
58. 14- In most cases, the scooped pedestrian falls or is flung off
on one side of the car or the other, again to suffer secondary
injuries in the road and perhaps be run over by another
vehicle.
15- The scooped-up victim will acquire the speed of the car by
the time he lands on the bonnet, but then the vehicle
decelerates. As the adhesion to the shiny surface is small, the
newly acquired velocity of the body will cause it to slide off the
front of the car as the latter brakes.
16- The victim then hits the ground in front of the car,
sustaining secondary injury - and may even be run over during
the residual motion of the vehicle before it finally stops.
17 - In a high-speed impact, which may be anything over 50
km/ hour the body can be flung high in the air and for a
considerable distance, either to the side or in the path of the
car - or even backwards over the roof.
59. 18- In general, the severity of the injuries – both primary and
secondary - will be the more severe the higher the speed. It is
impossible to estimate the speed of impact from the nature of the
injuries.
19- These can be fatal even at slow speeds of the order of 10
km/hour, yet occasionally high-speed impacts can produce only
minor damage.
20- When a pedestrian is struck by a larger vehicle, such as a van,
truck or bus, the initial point of impact is higher and may cause
primary damage to pelvis, abdomen, shoulder-girdle, arm or head.
21- Because of the profile of these vehicles, there is no scooping-
up effect, and the victim is usually projected forwards to suffer
secondary damage from road contact and sometimes to be run
over.
60. The severity of the injuries is related to many factors
Vehicle speed,
The angle of impact of the vehicle upon the pedestrian,
The center of gravity of the pedestrian,
The part of the body that first comes into contact with the vehicle,
The part of the vehicle the pedestrian impacts first & vehicle
design.
INJURIES TO PEDESTRIANS
1- The most common trauma is to the legs, some 85 per cent of
pedestrian casualties having lower limb injuries.
2- Abrasions and lacerations to the upper shin and knee area are
typical of car bumper contact, and fractures of the tibia and
fibula, often compound, are so common that they are present in a
quarter of fatalities, according to Eckert.
3- The femur is fractured less often. The mid-shaft may be broken
or the head may be driven into the acetabulum, together with a
fractured pelvis.
61. 4- If the leg is weight-bearing at the time of the impact, the tibia1 fracture
tends to be oblique, whereas if not lifting during walking, the fracture line is
often transverse.
5- When both shins are damaged, the level may be different on each side;
this indicates that the person was moving at the time, with one leg raised in
walking or running.
6- Traffic accidents are the most frequent cause of skull fracture, especially
of the base. Fractures of chest, arm and pelvis and injuries to the abdomen
follow in frequency
7- Often the injuries are concentrated on one side, usually on the opposite
side to the point of primary impact, because the body was thrown down
onto the road.
8- Because of rotation and the variable posture from being thrown off
the car structure, however, the injuries are often widespread and may
show no particular pattern.
62. 9- Soft tissue injuries are common and, apart from abrasions,
bruises and lacerations, muscle laceration and crushing can
occur.
10- A characteristic lesion from running-over, as opposed to
knocking-down, is the 'flaying' injury, where a rotating motor
wheel tears the skin and muscle from a limb or head.
11- The rotatory effect against a fixed limb may strip off almost all
tissue down to the bone.
12- When a wheel passes over the abdomen or pelvis, multiple
parallel striae or shallow lacerations may occur near the contact
area because of ripping tension in the skin.
13- When a wheel passes over the pelvis, abdomen or head, there
may be great internal damage with little surface injury.
14- The weight of a large vehicle can virtually flatten a head,
crushing the cranial vault. Often the brain is extruded through
scalp lacerations, as may be the intestine through an abdominal
wound.
63. 15- The pelvis may flatten out when run over, the symphysis or
superior rami breaking, and one or both sacroiliac joints
becoming detached.
16- Any type of intra-abdominal injury may occur from ruptured
liver and spleen to perforated intestine, lacerated mesentery and
fractured lumbar spine.
17- In the chest, ribs, sternum and thoracic spine may fracture,
and heart and lung damage occur from crushing or laceration
from jagged ribs.
18- A 'flail chest' is sometimes produced when a heavy wheel
runs across the supine body, breaking all the ribs on each side
in the anterior axillary line.
19- Patterned injuries may be important, in that they can assist
the police in identifying a vehicle in a 'hit-and-run‘ accident. The
most common is a tyre pattern outlined in intra-dermal bruising
and these should be measured carefully and photographed.
64. 20- These marks are usually caused by the skin being forced into
the grooves of the tyre tread, the edge of the raised rubber tracing
out the pattern. The elevated parts do not leave bruises, but may
imprint dirt on the skin.
21- Paint fragments and glass shards are also trace evidence that
must be carefully retained, as the forensic laboratory may be able
to identify the make and model of vehicle involved, and match the
fragments when a suspect car is examined.
22-Suprarenal haemorrhage is more common in the right gland
than the left after a traffic injury in Britain, but this observation
that many such haemorrhages occur several days after the trauma
and are usually the result of general systemic effects, rather than
direct impact.
65. INJURIES TO MOTORCYCLISTS
1- The rate of injury and death amongst motorcyclists is far higher
than among car drivers.
2-The two extremities of the body suffer most in motorcycle
accidents, though Larsen and Hardt-Madsen's analysis (1988)
showed high injury rates for chest and abdomen. Because the rider
inevitably falls to the ground, head injuries are common and often
severe,
3- Though crash helmets are mandatory in most countries, the
severity of the impact often defeats its protective effect. Impact with
the road surface or another vehicle at speed causes skull fractures
at any part of the head, but often temporoparietal.
4- A common complication is a basal skull fracture, especially a
'hinge' fracture. This transverse crack across the floor of the skull,
crossing the petrous base or behind the greater wing of the
sphenoid bones through the pituitary fossa to the opposite side, has
also been called 'the motorcyclist's fracture'.
66. 5- Another type is the ring fracture around the foramen magnum in
the posterior fossa caused by an impact on the crown of the head.
6- There are often cervical spine fractures found in over a quarter of
his series. Brain damage may be severe, even with a helmet in
place. Cortical contusion and laceration, sometimes contrecoup,
may be gross enough to cause brain tissue to extrude through
compound fractures of the skull.
7- In Mant's series of motorcyclists, 60 % had skull fractures and
almost 80 % had brain damage.
8- The legs are often injured, either by primary impact with another
vehicle or fixed road structures, or by becoming trapped by part of
the motorcycle frame. Lacerations, friction burns and fractures –
often compound - are common.
67. 9- Any part of the body may suffer injury, but less often than the
extremities. Falling from the machine, especially at speed, can
cause rib fractures and visceral damage, especially rupture of the
liver and spleen.
10- An injury common with motorcycles is the 'tail-gating‘
accident, where a rider drives into the back of a truck so that
the machine passes underneath, but the head of the motorcyclist
impacts upon the tail-board.
11- Decapitation may occur in the most extreme cases, but
severe head and neck injuries are almost inevitable.
68. INJURIES TO PEDAL CYCLISTS
1- These form a less severe counterpart of motorcycle lesions, as
the pedal cycle has the same instability but far lower speeds.
2- Head injuries figure largely in accidents, as the height above the
ground is considerable and the rider suffers from the passive fall,
added to by any forward motion or projection from impact by a
motor vehicle.
3- Other injuries are from the primary impact from a striking
vehicle, which may hit the rider around thigh, hip or chest level.
4- Secondary damage to the shoulder, chest and arm may occur
from striking the ground, when friction grazes are common.
5- (A unique injury, though not fatal, was entrapment of the leg
between wheel spokes with compression of the soft tissues of the
calf, when the leg penetrated the wheel.)
69. RAILWAY INJURIES
1- where a public road crosses a railway track with either no barrier at all or
with only a flimsy lifting pole. Many vehicles are struck each year by passing
locomotives.
2- Few rail passengers are killed or injured in moving trains compared with
accidents to railway staff and to other types of accident on railway property.
Track workers may be run down and some die from electrocution from
overhead cables.
3- The pathology of all these is no different from accidents elsewhere, the
malicious damage caused to trains, either by placing objects on the tracks,
which may cause a derailment, or the dropping of objects from bridges.
4- The other fairly common railway fatality is the suicide who lays himself in
front of an approaching train. Decapitation is the most common injury. and
the obvious features are the local tissue destruction, usually with grease,
rust or other dirt soiling of the damaged area. The usual search for alcohol
and other drugs
5- Jumping from the subway platform of an underground 'tube‘ or 'metro'
system. Here injuries are sometimes complicated by high-voltage electrical
lesions, as the typical traction voltage of an electric railway is in excess of
600 volts.