Transportation Injuries Chapter Notes | Forensic Medicine and Toxicology (FMT) - NEET PG PDF Download

Introduction

Road traffic accidents (RTAs) are the leading cause of fatalities among all types of traffic accidents and pose a serious global problem. Every year, approximately 1.2 million people die as a result of RTAs, with an additional 50 million suffering injuries.

While injuries and deaths can occur in any mode of transport, road, rail, and air transport systems are the most common sources of such incidents.

Trauma in Road Traffic Accidents

In India, the majority of medicolegal autopsies are performed on victims of vehicle-related accidents. RTAs primarily cause injuries to the limbs and face, whereas head injuries are usually internal. A comprehensive examination of the injuries is essential for understanding the circumstances surrounding the accident. The nature of the injuries can offer insights into the positions of both the victim and the vehicle at the time of the incident. Moreover, in 'hit and run' cases, the type of injuries and the collection of trace evidence from the victim can assist in linking the suspect vehicle to the incident. It may also be possible to determine if the vehicle ran over the victim.

Types of Trauma Sustained
Trauma resulting from transportation accidents can be categorized based on the type of victim:

• Trauma sustained by pedestrians
• Trauma sustained by cyclists/motorcyclists
• Trauma sustained by occupants of a vehicle

Trauma Sustained by Pedestrians

• When a pedestrian is struck by a vehicle, they can suffer from three different types of injuries: Primary impact injuries, Secondary impact injuries, and Tertiary injuries.

Primary Impact Injuries

• Primary impact injuries occur when a vehicle strikes a pedestrian, and different parts of the vehicle make forceful contact with the individual.
• A pedestrian can be hit from various angles: the front, back, or sides of the vehicle. However, most impacts happen at the front of the vehicle.
• The front of the vehicle can cause injuries through its bumper, radiator grill, headlights, and other components.
• Bumper fractures are a common type of injury caused when a pedestrian is struck by the bumper of a vehicle. These fractures typically occur in the leg bones.
• In hit-and-run cases, forensic experts can estimate the height of the bumper by measuring from the pedestrian's heel to the fracture site at the time of the accident. This measurement is usually slightly less than the actual height of the bumper because the car dips when brakes are applied suddenly.
• Injuries caused by the radiator grill and headlight rims can result in patterned abrasions and bruises on the pedestrian's body.
• Glass fragments and paint particles found on a pedestrian's clothing or skin can help forensic investigators link the vehicle to the incident.
• Identifying a primary impact injury is crucial for understanding the positions of both the pedestrian and the vehicle during the collision. This information can either support or contradict witness accounts of the accident.

Secondary Impact Injuries

• Initial Impact: When a person is hit by a vehicle, if the initial impact occurs below their centre of gravity (usually around the belly button), their feet might slide out from under them. This can lift their entire body off the ground and throw them into the vehicle's path.
• Children: The injury pattern in children can be different because their centre of gravity is lower in their bodies.
• Head Injury: After the secondary impact, the head may hit the windshield or a pillar of the vehicle.
• Torso Injury: The torso could collide with the bonnet or other parts of the car.
• Types of Injuries: During this secondary impact, various injuries can occur. Shattered pieces of the windshield, parts of the bonnet, and other vehicle components can cause contusions (bruises) and lacerations (cuts).
• Final Impact: After the secondary impact, the victim will be forcefully thrown onto the ground, resulting in further injuries.

Tertiary Impact Injuries

• Tertiary impact injuries, also known as secondary injuries, occur when the victim's body strikes the ground after a secondary impact.
• These injuries are most commonly seen in the head, and they can be fatal due to the severity of the ground impact.
• In certain cases, the victim may be run over by the vehicle, resulting in crush injuries.
• If the victim is run over and the tyres are not worn, distinct tyre marks may be visible on the body.
• It is essential to document the precise measurements and patterns of any visible tyre marks.
• Photographs of the tyre marks should be taken with a scale to allow for accurate comparisons with marks on the body.

Trauma Sustained by Cyclist/Motorcycle Rider

• The injuries sustained by cyclists and motorcycle riders in accidents are comparable to those of pedestrians. However, the initial impact typically occurs on the motorcycle itself.
• Secondary and tertiary injuries in these cases are often more severe.
• To aid in reconstructing the accident, it is crucial to examine the motorcycle involved.
• Evidence should be collected from both the motorcycle and the victim's body to get a complete picture of the incident.

Dynamics of transportation pedestrian injuries

Rate of Injury and Death

• The rate of injury and death for motorcyclists is significantly higher than for car drivers, particularly among young adults.
• This issue is less pronounced in older adults.
• The situation has improved to some extent due to laws mandating the use of protective gear, especially helmets, in several countries.

Injuries Sustained by Occupants of Vehicle During Collision

The occupants of a vehicle involved in a collision can suffer from various injuries depending on the force of deceleration and their position within the vehicle.

Driver

• Chest Injuries: The driver may experience an impact to the front of the chest against the steering column, particularly the horn boss. This can lead to rib and sternum fractures, as well as bruises and cuts to the lungs and heart.
• Aortic Rupture: There is a risk of aorta rupture during a collision.
• Head Injuries: The driver may sustain a head injury from hitting the windshield.
• Lower Limb Injuries: Fractures of the leg and thigh bones can occur due to force transmitted upwards from the pedals. Additionally, dislocation of the hip joint may happen from the upward force through the pedals.

Front Seat Occupants

• Chest Injuries: Front seat occupants may suffer similar chest injuries as the driver, including rib and sternum fractures, along with bruises and cuts to internal organs.
• Head Injuries: Front seat occupants are at risk of head injuries from hitting the dashboard or windshield.
• Lower Limb Injuries: Occupants in the front seat may also experience fractures and dislocations in the lower limbs due to the impact.
• Back Seat Occupants
• Chest Injuries: Back seat occupants can sustain chest injuries similar to those in the front seat, including rib and sternum fractures.
• Head Injuries: Back seat occupants are at risk of head injuries from hitting the back of the front seat or the roof of the vehicle.

Ejection from the Vehicle
In some cases, occupants may be ejected from the vehicle if a door opens during the collision, leading to additional injuries.

Injuries to Front Seat Occupants

• When a car is involved in a collision, occupants in Railway Disaster Trauman experience serious injuries by hitting the windshield and dashboard.
• The sudden stop can cause the neck to move abruptly, either forward or backward, which may lead to dislocation of the cervical vertebrae and possible damage to the spinal cord.
• This type of injury is commonly referred to as whiplash, as highlighted in various studies.
• The introduction of mandatory seat belt laws in many countries has significantly decreased the incidence of these injuries.

Back Seat Occupants

• Back seat passengers can sustain head and chest injuries from colliding with the front seat.
• There is also a risk of whiplash injuries.
• Passengers may be ejected from the vehicle.
• Seat belts are now required for all car occupants, which has reduced the frequency and severity of injuries in accidents.
• Since the advent of the railway engine, accidents have resulted in numerous deaths.
• Recent railway incidents have led to thousands of fatalities, highlighting the need for improved safety measures.
• Railways are a prevalent form of public transport worldwide, comprising an extensive network with many unprotected crossings.

Railway Disaster Trauma

Since the invention of the railway engine, train accidents have caused numerous deaths. As a widely used public transportation system globally, particularly in India with its extensive railway network and unguarded crossings, thousands have lost their lives in rail incidents over the years.

Classification

• Railway disaster trauma is divided into:
• Trauma resulting from collisions and derailments
• Falling from a speeding train
• Being struck by a speeding train

Collision and Derailment Trauma

• Victims may sustain injuries to the head, spine, and legs, similar to those seen in automobile accidents.
• Individuals sleeping on bunks may be propelled forward, resulting in dislocations or fractures of the vertebral column.
• Broken pieces of the carriage can lead to penetrating injuries.

Falling from a Speeding Train

• Victims falling from a speeding train may suffer numerous injuries across various body parts.
• Typically, bodies are found outside the tracks unless the victim falls between the train carriages.

Hit by a Speeding Train

• A speeding train can strike a victim who is crossing the tracks, walking along the railway line, or jumping in front of it.
• The impact can result in severe injuries, including decapitation and amputation of limbs, along with local tissue destruction and contamination from grease, rust, or dirt.
• The front bumper of the train engine, known as a cattle trap, can cause initial injuries similar to severe automobile accidents.
• During an autopsy, measuring the distance from the heel to each injury is crucial for future reconstruction.
• After the primary impact, victims are often thrown forward and may be run over, leading to dismembering injuries.
• A wide band of contusion collar around both sides of the amputation area is commonly observed.
• Track workers may also be at risk of accidental electrocution from high voltage overhead cables, resulting in injury patterns similar to those in other accidents.
• Victim remains scattered on both sides of the railway track should be measured against the track's breadth, indicating the position of the body at the time of the incident.
• If no other injuries are present, it suggests the victim was lying across the track.
• The body should be thoroughly examined for signs of violence, intoxication, or natural diseases.

Medicolegal Significance of Railway Disaster Trauma

• Autopsy Considerations: Any body found on the railway track requires a thorough autopsy to determine whether the injuries occurred before death.
• Cause of Death: Most fatalities are due to accidents or suicides. However, homicide victims may be placed on the tracks to simulate suicide.
• Delayed Death: In cases where a victim is run over, death may not be instantaneous, resulting in minimal or no vital reactions in the injuries.
• Appearance of Postmortem Injuries: Postmortem injuries typically appear dry and have a parchment-like texture.
• Bruising and Bleeding: There is usually little to no bruising around these injuries or redness at their edges, and excessive bleeding that would be expected from severe injuries is absent.
• Patterned Injuries: Similar to car accidents, patterned injuries may occur due to primary and secondary impacts, but they will be very severe.
• Suicide by Train:. common scenario in railway fatalities is suicide, where the individual lies in front of an oncoming train.
• Clean Decapitation:. clean decapitation with no additional injuries is indicative of suicide.
• Investigation of Medical and Social History: In cases of suspected suicide, it is essential to investigate the deceased's medical and social history to identify any immediate reasons for their decision to end their life.

Air Disaster Trauma

During the period between the two World Wars, there was limited research conducted by doctors on aircraft accidents. However, at the beginning of World War II, a systematic approach to investigating the medical and pathological aspects of aviation accidents was established, which has since developed into a specialized field of study.

Incidence

• The majority of aircraft accidents occur during the landing phase (55%. or during take-off (22%).
• The remaining accidents take place in the air during flight (23%).

Causes

• Aircraft accidents can be attributed to various causes, including:
• adverse weather conditions,
• poor visibility,
• engine malfunctions,
• lightning strikes,
• bomb explosions,
• fires onboard the aircraft.
• However, the most common cause of aircraft accidents is human error, often in conjunction with other factors.

Mechanism of Aircraft Injuries

Aircraft injuries can occur in two different ways during a crash.

Crash Accident Injuries
Passengers are usually secured with seat belts during take-off and landing. However, in the event of a crash, the sudden forward motion can cause the passenger's head and torso to collide with the seat in front, leading to various injuries, including:

• Fractures of the skull and cervical vertebrae due to the impact forces during a crash.
• Lacerations of abdominal organs such as the liver, spleen, and kidneys.
• Lacerations of major blood vessels in the abdomen, such as the aorta.
• Burns injuries, as approximately 20% of fatal crashes involve fire and conflagration.

Flight Accident Injuries
Aircraft cabins are typically pressurized to prevent anoxia. If a door or window fails, the cabin pressure drops, causing anoxia that can lead to death. The rapid decompression can also expel air forcefully, potentially ejecting passengers from the cabin and causing severe injury or dismemberment.

Medicolegal Importance

All injuries mentioned, such as those from railway accidents or aircraft cabin depressurization, are classified as examples of mass disaster injuries due to their potential to cause widespread harm and fatalities in large-scale incidents.

Intoxication

• It is crucial to consider intoxication in all transportation incidents. This includes potential impairment from alcohol, medications such as antidepressants, hypnotics, antipsychotics, and illegal drugs like cannabis and heroin.
• Investigations into deaths resulting from transportation incidents, including aircraft crashes, are not comprehensive without testing the victim's blood and urine for these substances.
• Drivers of vehicles involved in such accidents should also be screened for alcohol and other drugs.