Transportation Injuries PDF

Transportation Injuries Dr. Isam ELHASSAN  Medico-legal importance of autopsies in motor car accidents: 1- To determine the cause of death. 2- To confirm that death has occurred due to injuries caused by the accident. 3- To determine the extent of these injuries. 4- To detect any diseas...

Transportation Injuries Dr. Isam ELHASSAN  Medico-legal importance of autopsies in motor car accidents: 1- To determine the cause of death. 2- To confirm that death has occurred due to injuries caused by the accident. 3- To determine the extent of these injuries. 4- To detect any disease that could precipitated the accident. 5- To detect any criminal activity. 6- To establish identification of a body especially when burnt or mutilated.  Causes of motor vehicle accidents: 1- Impairment of the consciousness of the driver as by alcohol &/or drugs. 2-Natural diseases of the driver as heart disease, epilepsy, diabetes. 3-Speed, fatigue, and careless driver. 4-Defects of the vehicle e.g break 5-Environmetal factors as raining, winds, and bad construction of roads.  Factors affecting severity & mechanisms of injury: 1- Speed of the vehicle. 2- Physical characteristics of the vehicle. 3- Whether the vehicle is breaking or not. 4- Age and body built of the victim.  Non-pedestrian (vehicle occupants) injuries: Dynamics of vehicular injury: 1- Tissue injury is caused by a change of rate of movement (acceleration/deceleration). A constant speed, however rapid, has no effect. 2- During acceleration or deceleration the tissue damage produced will depend upon the force applied per unit area. 3- Frontal impact causes violent deceleration, rear impacts accelerate the vehicle and its occupants. Sometimes the impact of the vehicle causes side-swipes & “roll-overs”.  Non-pedestrian (vehicle occupants) injuries: Dynamics of vehicular injury: 60- 80 % of vehicular crashes are frontal impact i.e violent deceleration. 6% rear impacts, accelerate the vehicle and occupants. The remainders are side wipes and roll- overs.  Patterns of non-pedestrian (vehicle occupants) injuries: The Driver :- In frontal impact the unrestrained driver first slides forwards so that his legs strikes facial / parcel self area. The body then flexes across the steering wheel and begins to rise with flexion of the cervical and thoracic spines. The head strikes the wind screen and the whole body may be ejected through the broken glass to land on the bonnet or even the roadway ahead. Secondary; intrusion of structure parts into the passenger compartment, column, engine, gearbox intrusion to the driver feet and legs. The door may burst open and the driver ejected sideways (if unrestrained) especially in a crash that has a roll over components.  Patterns of non-pedestrian (vehicle occupants) injuries: The Driver :- In rear impact violent acceleration if no rigid head restraint is fitted there will be severe hyperextension of neck followed by hyper flexion a whiplash injury. In side impacts The injuries depend upon the amount of intrusion of the driver’s door.  Patterns of non-pedestrian (vehicle occupants) injuries: If a driver not wearing seatbelt or protected by air-bags the following lesions can be produced: Abrasions, lacerations and fractures of legs around knee. Fractures any where from foot to femur, posterior dislocation of the hip joints. Steering wheel injuries ; ruptured liver (50%) spleen (36%) – bruising of the lungs, fractured ribs and sternum – haemothorax, pneumothorax Multiple face cuts from contact with the shuttered safety glass.superficial lacerations short V- shaped or sparrow foot patterns.  Patterns of non-pedestrian (vehicle occupants) injuries: Scalp lacerations, fractured skull, intracranial haemorrhage, brain damage (40% of driver had fracture of the skull). dislocation at the altanto-occipital joints. Ruptured aorta ‘due to pendulum effect of the heart’ the site at the termination of the aorta arch where the aorta is attached to spine  Patterns of non-pedestrian (vehicle occupants) injuries: The pattern of injuries in front seat passenger is similar to that of the driver (la place due Mort). The most dangerous place inside the car is the front seat beside the driver. Usually the driver sustained lesser severe injuries compared to the other front seat occupant. Patterns of non-pedestrian (vehicle occupants) injuries: Injuries to Motorcyclists:- ◦The rate of injury and death amongst motorcyclists is far higher than drivers because: the rider inevitably falls to the ground head injuries are common and often severe causing 80% of deaths. ◦The wearing of crash helmets is mandatory in most countries. Patterns of non-pedestrian (vehicle occupants) injuries: Common complications :- ◦ basal skull fracture a hinge fracture – motorcyclist’s fracture- transverse crack across the floor of the skull crossing the petrous base or behind the greater wing of the sphenoidal bones through the pituitary fossa to the opposite side. ◦ Ring fracture around the foramen magnum. In the posterior fossa ( landing on the top of the head). ◦ leg injury, pelvis injuries in approximately 55% of cases. Safety helmets acts by :- ◦ Providing a rigid barrier. ◦ Designed to skid across the road surface, lengthening the stopping time and distance. Reduce the G force of deceleration.  Pedestrian injuries: Dynamics of pedestrian injury: 1- Unlike injuries related to vehicle occupants, its an acceleration not a deceleration process. 2- The most frequent type of pedestrian accident is the struck of the victim by the front of the car. 3- The injuries are divided into primary injuries that are caused by the 1st impact of the vehicle on the victim. While secondary injuries are caused by subsequent contact with the ground. 4- After pedestrian, the driver of the vehicle is the most frequent fatal casualty in road traffic accidents. Next in frequency is the front seat passenger, followed far less frequently by rear seat passenger. The most common trauma is to the legs. Abrasions and lacerations of the upper shin and knee area are typical of car bumper contact, and fractures of tibia and fibula often compound are so common. At autopsy the skin of the lower limbs leg should be incised to seek deep bruising as the clothing often protect the surface from obvious marking. The tibia is often fractured in a wedge-shaped manner, the base of the wedge indicates the direction of the impact (often from behind). If the leg is weight-bearing at the time of the impact the tibia fracture tends to be oblique when lifted during walk the fracture line is often transverse. The head is the next most frequently damaged region because of impact with windscreen, pillars and roof together with secondary contact with the ground. Soft tissue injuries are common, muscle lacerations and crushing. a characteristic lesion from running-over is flaying injury where the rotating motor wheel tears the skin and muscle from limb or head. Crashed skull, abdomen , pelvis in run-over. Patterned injuries are important in assisting the police to identify a vehicle in a hit and run incidents. Tyre pattern- intradermal bruises-should be measured carefully Paint fragments and glass shreds and other trace evidences collected for identification of the suspected car.  Autopsy on a road traffic accident: The autopsy is in general identical to the usual procedure, but with special attention to the following points: 1- Identity of the body must be assured. 2- The clothes should be examined and injuries can be matched against soiling and damage to the garment. 3- External examination: As in all trauma, the height of major or patterned injuries must be recorded, in order to compare against dimensions of a vehicle. 4- Autopsy: A full autopsy must be carried out. The presence of any natural disease such as old or recent cardiac disease & cerebral lesions, is relevant especially if it might have contributed to the accident, either by causing a driver to loose control or a pedestrian to exercise a proper behaviour in the roadway. 5-Sample collection & laboratory examination: - Blood samples must be retained for blood grouping and DNA fingerprinting. In case of ‘hit-and-run’ vehicle, blood & hair samples are taken in order to identify the vehicle responsible for the accident. - When death occurs within 12-24 hours of the time of the accident, blood analysis for alcohol is essential whether in driver or pedestrian. Where possible, screening for drugs of dependence and common substances that might have caused drowsiness, should be carried out. - In certain cases, where leakage of CO is suspected, the circumstances will suggest analysis of the blood for carboxy-hemoglobin concentration. The end