1. Motor Vehicle Accidents
FORENSIC PATHOLOGY
Motor Vehicle Accidents

2. MOTOR VEHICLE ACCIDENTS
Why perform an autopsy after a MVA?
Determine cause of death
Confirm death was caused by injury in the MVA
Determine extent of injuries
Detect any disease or factor which may contribute to MVA
Document findings for criminal or civil case
Establish positive ID of body

3. MOTOR VEHICLE ACCIDENTS
Causes of MVA
Impairment of driver is most common
50% of all crashes are due to DUI of alcohol or drugs
Drugs may be prescription
Even marijuana impairs driving skills
2nd cause is human error
Speed, reckless driving, falling asleep at wheel
3rd cause is environmental hazards

4. MOTOR VEHICLE ACCIDENTS
Four Major Categories of MVA’s in descending order of fatality for automobiles
Front impact
Side impact
Rollovers
Rear impact

5. MOTOR VEHICLE ACCIDENTS
Four major categories of MVA’s for pickups and utility vehicles in descending order of fatalities
Rollovers
Frontal impact
Side impact
Rear impact

9. MOTOR VEHICLE ACCIDENTS
Front Impact Crashes
In a head on collision if the driver is not restrained the body will continue its frontal movement
Strike instrument panel at knees
Strike chest on steering wheel
Strike head on windshield of visor

10. MOTOR VEHICLE ACCIDENTS
Front Impact Crashes
Knees
May have patterned abrasions
Fractures of the patella
Fractures of the femur or hip joint
Especially neck of femur
Exsanguination may occur

11. MOTOR VEHICLE ACCIDENTS
Front Impact Crashes
Chest
May impact steering wheel or dashboard
Imprinted abrasions/contusions
Internal injuries
Fracture of sternum and/or ribs
Lacerations, contusions, rupture, transection of vital organs
Liver, spleen, heart, aorta

12. MOTOR VEHICLE ACCIDENTS
Front Impact Crashes
Head
Patterned abrasions
Impact windshield
Windshield does not shatter
Thin outer and inner layers of glass, thick core of plastic
Dicing injuries
Avulsion of skin especially to head
Basilar fractures of skull
Hinge fractures
Fractures of neck
Atlanto-occipital junction dislocation

13. MOTOR VEHICLE ACCIDENTS

14. MOTOR VEHICLE ACCIDENTS
Unrestrained injuries usually occur in sequence
Knee-femur-hip-chest-head
Restrained injuries are dependent on the force of the crash

15. MOTOR VEHICLE ACCIDENTS

16. MOTOR VEHICLE ACCIDENTS
Side Impact Crashes
Broadside at intersections most common
Driver’s side
Head can flex laterally through side window
Head may hit pillar of car
Injuries are typically worse on left side of body
Head may pop out of window and pop back into vehicle
Head may hit objects before re-entering vehicle

17. MOTOR VEHICLE ACCIDENTS
Rollovers
Generally less lethal than head-on and side impact collisions
If not wearing seatbelt may be thrown around like a rag doll in compartment
Receive multiple injuries
Body may also pop out of vehicle and pop back in again
Check for paint on head or hair on vehicle

18. MOTOR VEHICLE ACCIDENTS
Rollovers
Most rollovers occur because driver runs off the road and attempts to steer back onto road
Vehicle skids sideways
Vehicle tips towards leading side
Where rollover begins is where tire marks stop
Center of gravity determines extent of rollover
SUV’s rollover more

19. MOTOR VEHICLE ACCIDENTS
Rollovers
Vehicles that roll over go airborne
Cars land on edge of roof opposite side that led in rollover
SUV’s impact on leading edge of vehicle roof then onto tires
Most vehicles only roll over once

20. MOTOR VEHICLE ACCIDENTS
Rear Impact Crashes
Least common of fatal accidents
Mainly see whiplash syndrome
May have fire due to faulty gas tank
May have seatback failure

21. MOTOR VEHICLE ACCIDENTS

22. MOTOR VEHICLE ACCIDENTS
Seat belts
Lap belts
Shoulder belts
Three-point belts
Lap plus shoulder

23. MOTOR VEHICLE ACCIDENTS
Seat belts
All new vehicles have three-point belts
Since 1997, 69% decrease in MVA fatalities due to seat belt law
Jack-knifing may occur with lap belts
Seat belt syndrome

24. MOTOR VEHICLE ACCIDENTS
Air bags
Significantly less effective than seat belts
Only improves your chance of survival by a maximum of 5%
May produce injuries especially in children and small adults
Less than 10 inches from bag

25. MOTOR VEHICLE ACCIDENTS
Motorcycle Accidents
Fatalities are due mostly to head or neck injuries
Many abrasions
High speed crashes wearing helmets are only to keep brain matter from spreading over the freeway

26. MOTOR VEHICLE ACCIDENTS
Motorcycles
Most fatalities are due to
Car drivers don’t see the motorcycle
Environmental factors
Wires or cables stretched across roadway
Avulsed limbs
Decapitation

27. MOTOR VEHICLE ACCIDENTS
Suicide by Motor Vehicle
Usually head on into a fixed object
Check soles of shoes of driver for pedal marks
May also do this to determine who was driving in a crash

28. MOTOR VEHICLE ACCIDENTS
Toxicology and MVA’s
A complete toxicological screen should be done
Include Carbon Monoxide levels
In 1999, 38% of traffic fatalities were alcohol related down from 49% in 1989
Should also drug test passenger
Passenger often turns out to be driver
Blood may be kept at a hospital for up to 7 days

29. MOTOR VEHICLE ACCIDENTS
Pedestrian Deaths by MVA’s due to four factors
Speed of vehicle
Physical characteristics
Braking of vehicle
Whether victim was a child or an adult

30. MOTOR VEHICLE ACCIDENTS
Pedestrian Death – Speed of Vehicle
Fracture of spine, 45 km/h
Rupture of thoracic aorta, 85 km/h
Inguinal skin rupture, 95 km/h
Dismemberment, above 95 km/h

31. MOTOR VEHICLE ACCIDENTS
SUV’s
Child Pedestrians
Body’s center of gravity is below bumper
For non-braking or late braking vehicle: Victim will be impacted, slammed down and run over
For braking vehicle: Front of vehicle dips below child’s center of gravity and child may be thrown forward

32. MOTOR VEHICLE ACCIDENTS
Adult Pedestrians
Body’s center of gravity is above bumper, except for tall vehicles, i.e. pick-up or SUV
Trucks or SUV’s
Non-braking: Victim is slammed down and run-over
Braking: Victim is thrown forward

33. MOTOR VEHICLE ACCIDENTS
Adult Pedestrians
Automobiles or light trucks
Non-braking or late braking at high speeds: Victim is picked up and thrown over top of car
Look for scuff marks or dents on bumper, hood, roof and possible trunk of vehicle
Non-braking at moderate speeds: Victim will be picked up, land on the hood and slide backward impacting windshield, then slide off (usually sideways)
Look for scuff marks or dents on bumper, indent on hood and impact to windshield
Glass may be in hair of victim
May find hair or clothing in cracks in paint or in glass on vehicle

34. MOTOR VEHICLE ACCIDENTS
Automobile or Light trucks
Braking at high speeds: Victim may be thrown forward or may be picked up and land on the hood and then propelled forward again
Look at knees and calf region for fractures
“Bumper Fractures”
If walking or standing sideways may be fractures at different levels or fracture in only one leg

35. MOTOR VEHICLE ACCIDENTS
Automobile or light truck
Individuals picked up and thrown by a vehicle may be stripped of clothing
If Victim is run over by a wheel
Look for tire marks and abrasions on opposite side of body

36. MOTOR VEHICLE ACCIDENTS
Future of MVA’s
Black Boxes
Already in Mercedes and
All GMAC models

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