Pantallas entrenamiento

7.2.1 Crash Reconstruction I

On a clear evening in November, 2005, a young male driver of a 2000 Nissan Cedric (1604 kg) was attempting to make a left (southbound) turn at an intersection un- controlled by a traffic signal light in Riyadh. As the driver was completing the left turn and crossing the intersection, a pedestrian (38 years-male, 168 cm, 88 kg) emerged quickly from behind a small building on the right side of the passenger car and proceeded to cross the road at a non pedestrian sidewalk. The driver was unable to avoid the pedestrian due to the shadow cast by the building, and struck the pedestrian at an estimated speed of 34 km/h.

The car’s bumper struck the man’s left leg projection him up onto the bonnet, his head striking the windshield. He then rolled onto the bonnet and was thrown away for 5 m onto the ground. Damage to the vehicle included a dent on the grill and a large dent on the bonnet (0.54 m from front right corner of bonnet and 0.45 m back from the front of the bonnet). Evidence of pedestrian contacts on the car is shown in Figure 7.2.

The pedestrian was transported by EMS to King Fahad Hospital trauma center with a

Glasgow Coma Scale (GCS) of 9. He was placed in a cervical collar and on a backboard at

the scene. He reportedly lost consciousness, but was alert and oriented on arrival at EMS and remained so throughout transportation. The paramedics noted severe left shoulder pain.

During reconstruction using PC-Crash based simulations, a number of scenarios were simulated. One scenario that appeared likely was when the car had an initial speed of 30 km/h, and the pedestrian had an initial speed of 7 km/h based on a reasonable walking speed (Ishaque and Noland, 2006) and the car orientation during impact being -100 with the lane and pedestrian orientation was 1100 with the same lane.

Figure

Figure 7.3

reconstructed case was validated by impact positions (t leg and the car’s windshield struck the man’s head)

the bonnet and was then thrown away for 5 m on the ground).

Figure 7.2: Scene diagram and the contact locations of the pedestrian on the car

Figure 7.3

reconstructed case was validated by impact positions (t d the car’s windshield struck the man’s head)

the bonnet and was then thrown away for 5 m on the ground).

Figure 7.3: PC

7.2: Scene diagram and the contact locations of the pedestrian on the car

Figure 7.3 shows the sequential events of PC

reconstructed case was validated by impact positions (t d the car’s windshield struck the man’s head)

the bonnet and was then thrown away for 5 m on the ground).

Figure 7.3: PC

7.2: Scene diagram and the contact locations of the pedestrian on the car

shows the sequential events of PC reconstructed case was validated by impact positions (t

d the car’s windshield struck the man’s head)

the bonnet and was then thrown away for 5 m on the ground).

Figure 7.3: PC-Crash simulations for crash of pedestrian in Case 1 7.2: Scene diagram and the contact locations of the pedestrian on the car

shows the sequential events of PC reconstructed case was validated by impact positions (t

d the car’s windshield struck the man’s head)

the bonnet and was then thrown away for 5 m on the ground).

Crash simulations for crash of pedestrian in Case 1 7.2: Scene diagram and the contact locations of the pedestrian on the car

shows the sequential events of PC reconstructed case was validated by impact positions (t

d the car’s windshield struck the man’s head)

the bonnet and was then thrown away for 5 m on the ground).

Crash simulations for crash of pedestrian in Case 1

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7.2: Scene diagram and the contact locations of the pedestrian on the car

shows the sequential events of PC reconstructed case was validated by impact positions (t

d the car’s windshield struck the man’s head) and final positions ( the bonnet and was then thrown away for 5 m on the ground).

Crash simulations for crash of pedestrian in Case 1 7.2: Scene diagram and the contact locations of the pedestrian on the car

shows the sequential events of PC-Crash simulation in this case. reconstructed case was validated by impact positions (the car’s bumper struck the man’s left

and final positions ( the bonnet and was then thrown away for 5 m on the ground).

Crash simulations for crash of pedestrian in Case 1 7.2: Scene diagram and the contact locations of the pedestrian on the car

Crash simulation in this case. he car’s bumper struck the man’s left and final positions (

Crash simulations for crash of pedestrian in Case 1 7.2: Scene diagram and the contact locations of the pedestrian on the car

Crash simulation in this case. he car’s bumper struck the man’s left and final positions (the man rolled onto

Crash simulations for crash of pedestrian in Case 1 7.2: Scene diagram and the contact locations of the pedestrian on the car

Crash simulation in this case. he car’s bumper struck the man’s left

the man rolled onto

Crash simulations for crash of pedestrian in Case 1 7.2: Scene diagram and the contact locations of the pedestrian on the car

Crash simulation in this case. This he car’s bumper struck the man’s left the man rolled onto

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7.2.2 Mechanisms of Spinal Injury

The pedestrian subsequently underwent a head, cervical spine and abdominal-pelvic Computed Tomography (CT) scan. The laboratory studies demonstrated a skull base fracture that extends through the occipital condyle (Type II) and pelvic fracture at the sacroiliac complex as shown in Figure 7.4. In addition, there were multiple other injuries including head, facial, multiple thorax, abdomen, and extremities injuries (see Table 7.1).

Figure 7.4: Radiographic images of spinal injuries for pedestrian in Case 1: left, axial CT scan shows Type II right occipital condyle fracture extending through skull base; right,

plain radiograph of open-book pelvic fracture

The hypothesised mechanism of injury to the occipito-atlantal joint, dictated by the pedestrian kinematics, involves hyperextension of the cervical spine. It is believed that when the legs of the pedestrian impacted on the bumper corner, a rapid rotational acceleration was applied to the long axis of the body during the scooping-up- motion. The strike by the head and face body regions with the windscreen produced a transitional force causing extension at the occipital with concomitant sheering. This series of events resulted in complete disruption of the occipito-atlantal ligament complex and C0/C1 dislocation.

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Table 7.1: Type of injuries sustained by pedestrian in Case 1

Injury ISS Body

Region AIS

Source of Injury

Subarachnoid hemorrhage of cerebellum Head 140466.3 Ground Dislocation fracture of atlanto-occipital joint Cervical spine 650228.3 Ground Laceration, left temple to the upper scalp Head 110602.1 Windshield Bruising is present behind the left ear Head 110402.1 Windshield Multiple fractures of the zygomatic bones Face 251800.2 Ground

Nose fracture Face 251000.1 Ground

Upper lobe of the left lung is traumatised Thorax 441499.3 bonnet edge The liver shows some bruising Abdomen 541810.2 Bonnet edge The spleen shows multiple lacerations Abdomen 544220.2 Bonnet edge The left kidney is contused Abdomen 541610.2 Bonnet edge

Disruption of sacroiliac joint Sacral 852604.3 Ground

Mid-shaft fracture of right femur Extremities 851814.3 Bonnet edge Right tibia multiple compound fractures Extremities 853404.2 Bonnet edge

Tibia contusion Extremities 853402.1 Front grill

Shallow Lac's on the left shoulder 11 × 5 cm Extremities 710602.1 Front grill Fractured left hip, NFS Extremities 852600.2 Bumper

ISS 27

Occipital condyle fractures seem to be rare. These injuries are typically indicative of high-velocity blunt force trauma (Anderson and Montesano, 1988). The most frequently encountered occipital condyle fractures are Type I, Type II, and Type III (Bell, 1817). Blunt force trauma secondary to a motor vehicle collision has been reported as the most common cause of occipital condyle fractures (Momjian, 2003).

Casualties with occipital condyle fractures resulting from motor vehicle collisions have been diagnosed with other blunt trauma and torsion injuries such as atlanto-axial dislocation, duodenal hematoma, and lumbar vertebra fractures and etc (Kaushik et al., 2002).

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Table 7.2: Haddon' s matrix for pedestrian in Case 1

Phase

Factor

Host Vehicle Environment

Pre-event

• Driver inattention

• Pedestrian awareness

• Pedestrian not wearing a reflective clothes

• Brakes in proper working order

• No anti lock brakes

• No crosswalk

Event

• Middle aged pedestrian

• Strong bone strengths

• Low bumper

• High speed

• Driver not wearing safety belt

• Road surface

Post-Event • Middle aged pedestrian in

good physical condition

• Proper tire tread for stopping

• Lack of EMS