Motor Vehicle Collisions, Restraints, and Airbags Practice Questions

25 multiple-choice questions on Motor vehicle collisions, restraints, and airbags for paramedic and EMT students, from Chapter 30 (Trauma Systems and Mechanism of Injury). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. The five basic types of motor vehicle collision are frontal, lateral, rear-end, rollover, and:

   1. A. Vertical
   2. B. Compressive
   3. C. Penetrating
   4. D. Rotational
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   Answer: D. Rotational

   Rotational impacts occur when one corner of a vehicle is struck and it spins, combining frontal and lateral injury patterns. Compression is a force, not a collision type.

2. In a frontal impact, an unrestrained occupant who follows the down-and-under pathway is most likely to injure the:

   1. A. Knees, femurs, and hips
   2. B. Face, skull, and cervical spine
   3. C. Clavicles and lateral ribs
   4. D. Wrists and forearms
   Show answer

   Answer: A. Knees, femurs, and hips

   The knees strike the dashboard and the force travels up the femur, causing femur fractures and posterior hip dislocation. Head and neck injuries belong to the up-and-over pathway.

3. An unrestrained driver's knees struck the dashboard in a frontal crash. His right leg is shortened, flexed, and rotated inward. You should suspect:

   1. A. Anterior hip dislocation
   2. B. Posterior hip dislocation
   3. C. Isolated fracture of the patella
   4. D. Isolated tibial plateau fracture
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   Answer: B. Posterior hip dislocation

   Force up the femur drives the femoral head backward out of the acetabulum, leaving the leg flexed, adducted, and internally rotated. Anterior dislocation causes external rotation instead.

4. In the up-and-over pathway of a frontal collision, the occupant's head commonly strikes the:

   1. A. Side window
   2. B. Rear headrest
   3. C. Door pillar
   4. D. Windshield
   Show answer

   Answer: D. Windshield

   A starred, bull's-eye windshield suggests head and cervical spine injury. Side windows are struck in lateral impacts.

5. A driver took a deep breath and held it just before his chest hit the steering wheel. This can rupture the lungs and cause a pneumothorax, a pattern called:

   1. A. Paper bag syndrome
   2. B. Battle's sign
   3. C. Waddell's triad
   4. D. Beck's triad
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   Answer: A. Paper bag syndrome

   Compressing a closed, air-filled lung against a closed glottis pops it like a paper bag. Waddell's triad describes pediatric pedestrian injuries.

6. After a frontal crash, the steering wheel is bent and the driver has upper abdominal pain. You should suspect injury to the:

   1. A. Bladder and urethra
   2. B. Kidneys and ureters
   3. C. Liver and spleen
   4. D. Appendix and colon
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   Answer: C. Liver and spleen

   The lower steering wheel rim hits the upper abdomen, where the liver and spleen are vulnerable to compression. The bladder is a pelvic organ injured by lap belts and pelvic fractures.

7. Lateral (T-bone) impacts are especially dangerous because:

   1. A. There is little structure between occupant and impact
   2. B. Airbags are not designed to deploy in side impacts
   3. C. Occupants are thrown into the windshield every time
   4. D. Side impacts typically happen at much higher road speeds
   Show answer

   Answer: A. There is little structure between occupant and impact

   Only a door separates the occupant from the striking vehicle, so less energy is absorbed before it reaches the body. Many cars now have side airbags, which reduce but do not eliminate the risk.

8. A car's automatic crash notification system reports data consistent with a high risk of severe injury to the occupants. Under the 2021 field triage guideline, this is:

   1. A. A red criterion requiring a Level I center
   2. B. A yellow high-risk crash criterion
   3. C. Not used, since it is not an exam finding
   4. D. Relevant only if the airbags deployed
   Show answer

   Answer: B. A yellow high-risk crash criterion

   Vehicle telematics consistent with a high risk of injury is listed with ejection, intrusion, and death in the same compartment as a yellow (moderate-risk) high-risk crash mechanism that directs transport to a trauma center. Red criteria are injury patterns and abnormal mental status or vital signs. Airbag deployment alone is not a criterion.

9. Lateral impacts commonly produce which pelvic injury?

   1. A. Open-book (anterior-posterior) fracture
   2. B. Straddle fracture of the pubic rami
   3. C. Lateral compression fracture
   4. D. Avulsion of the iliac crest
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   Answer: C. Lateral compression fracture

   Force driven into the side of the pelvis compresses it inward. Open-book fractures usually come from anterior-posterior force such as a motorcycle crash or a crush between objects.

10. In a lateral impact, the occupant's head tends to move:

    1. A. Straight forward into the steering wheel hub
    2. B. Backward over the top of the seat
    3. C. Downward into the floor board
    4. D. Toward the impact as the body is pushed away
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    Answer: D. Toward the impact as the body is pushed away

    The torso is pushed away from the impact while the head lags behind, causing lateral neck flexion, rotation, and spinal injury. Forward head movement is the frontal pattern.

11. A rear-end collision most classically causes:

    1. A. Bilateral femur fractures
    2. B. Lateral compression of the pelvis
    3. C. Splenic rupture from the door
    4. D. Hyperextension injury of the neck
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    Answer: D. Hyperextension injury of the neck

    The seat pushes the torso forward while the head lags, and the neck hyperextends when the headrest is too low. A properly positioned headrest, level with the top of the head, reduces this injury.

12. After the initial hyperextension in a rear-end collision, the occupant may suffer a second injury if:

    1. A. The car then strikes the car ahead of it
    2. B. The airbag fails to deploy in the rear
    3. C. The occupant is wearing a seat belt
    4. D. The car has a properly adjusted headrest
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    Answer: A. The car then strikes the car ahead of it

    Striking a car ahead adds a frontal impact with flexion of the neck after the hyperextension. A properly adjusted headrest is protective, not a cause of injury.

13. Rollover collisions are particularly dangerous mainly because:

    1. A. Occupants take one single large impact
    2. B. Seat belts often fail to hold in rollovers
    3. C. Occupants may be struck from any direction or ejected
    4. D. Airbags cause most of the injuries in rollover crashes
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    Answer: C. Occupants may be struck from any direction or ejected

    The occupant hits the interior at many points and unrestrained occupants are often ejected. Ejected patients are far more likely to die than those who stay in the vehicle. A rollover delivers many impacts rather than one, and a properly worn seat belt holds in a rollover and greatly reduces ejection.

14. A rotational (spin) collision typically produces:

    1. A. Injuries limited to the lower extremities
    2. B. A combination of frontal and lateral injuries
    3. C. Isolated hyperextension injury of the cervical spine
    4. D. No injuries if seat belts were worn
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    Answer: B. A combination of frontal and lateral injuries

    As the vehicle spins, occupants move in several directions, mixing patterns from both impacts. Seat belts reduce but do not prevent injury.

15. A lap belt worn too high, above the iliac crests, can cause:

    1. A. Lumbar spine fractures and bowel injury
    2. B. Posterior hip dislocation and femur fracture
    3. C. Clavicle fracture and neck lacerations
    4. D. Facial fractures and dental trauma
    Show answer

    Answer: A. Lumbar spine fractures and bowel injury

    A high lap belt lets the abdomen fold over it, compressing hollow organs and causing flexion-distraction (Chance) fractures of the lumbar spine. Femur fractures come from knees striking the dashboard.

16. A restrained passenger has a bruise across the lower abdomen in the shape of the lap belt. This finding should make you suspect:

    1. A. A minor bruise limited to the skin
    2. B. Intra-abdominal injury
    3. C. A fractured clavicle or sternum
    4. D. A strain of the cervical spine
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    Answer: B. Intra-abdominal injury

    The seat belt sign is associated with hollow organ and mesenteric injury and lumbar spine fractures. It also shows that the belt absorbed significant force. Clavicle, sternal, and neck injuries come from the shoulder portion of the belt; a mark across the lower abdomen points to the lap belt and the organs beneath it.

17. An occupant wore only the shoulder belt, without the lap belt. The occupant is at risk of:

    1. A. Femur fractures from the shoulder belt strap
    2. B. Lateral compression pelvic fracture
    3. C. Sliding under the strap with neck injury
    4. D. Isolated posterior shoulder dislocation
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    Answer: C. Sliding under the strap with neck injury

    Without the lap portion, the body slides under the shoulder strap, which can injure the neck. The lap and shoulder belt must be worn together to work properly.

18. Airbags are designed to be most effective in:

    1. A. Rollover collisions without seat belts worn
    2. B. Multiple impacts of the same vehicle
    3. C. Rear-end crashes at low speeds
    4. D. Frontal collisions combined with seat belts
    Show answer

    Answer: D. Frontal collisions combined with seat belts

    Frontal airbags inflate once and quickly deflate, so they offer little protection in rollovers or secondary impacts. They are a supplemental restraint system and work with belts, not in place of them.

19. After a frontal crash, a belted driver has abrasions on his face and inner forearms, burning, irritated eyes, and a fine white powder on his clothing. The most likely cause of these findings is the:

    1. A. Driver's frontal airbag
    2. B. Shattered windshield glass
    3. C. Rim of the steering wheel
    4. D. Battery acid from the engine
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    Answer: A. Driver's frontal airbag

    A deploying airbag strikes the face and the forearms held up on the wheel, causing abrasions, and the propellant and powder residue irritates the eyes and leaves a white dust that is not toxic smoke. Windshield glass causes lacerations, usually from the up-and-over pathway in unbelted occupants, not powder or eye burning in a belted driver. The steering wheel rim causes chest and upper abdominal injury, not facial abrasions with eye irritation. Battery acid rarely reaches the occupant compartment and does not explain the abrasion pattern. Irrigate the eyes and still assess for steering wheel and deceleration injuries.

20. Children under 13 should not ride in the front seat with an active passenger airbag because:

    1. A. The airbag will not deploy for small children
    2. B. The airbag can cause fatal head and neck injury
    3. C. They cannot reach or fasten the seat belt latch
    4. D. Child safety seats cannot be belted in front
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    Answer: B. The airbag can cause fatal head and neck injury

    An airbag inflates at around 200 mph, and rear-facing seats in front of an airbag are especially dangerous. Children are safest belted in the back seat.

21. Using the 5-10-20 rule, how far should a rescuer stay from an undeployed frontal passenger airbag?

    1. A. 5 inches
    2. B. 10 inches
    3. C. 20 inches
    4. D. 30 inches
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    Answer: C. 20 inches

    Keep 5 inches from side airbags, 10 inches from driver's airbags, and 20 inches from passenger airbags, since these can deploy during extrication. Ten inches is the driver's airbag distance.

22. A driver who was not wearing a seat belt sat close to the steering wheel when his airbag deployed. Compared with a belted driver, he is more likely to have:

    1. A. Lap belt injuries to the bowel
    2. B. No injuries because the airbag protected him
    3. C. Fewer chest and face injuries
    4. D. Injuries from the airbag itself
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    Answer: D. Injuries from the airbag itself

    Unbelted occupants slide toward the airbag as it deploys and can suffer facial, neck, and chest injuries from it. The airbag supplements the seat belt and does not fully protect without it. Without a belt he cannot have lap belt injuries, and sitting close to the wheel raises rather than lowers his risk of chest and face injury.

23. Which vehicle damage finding suggests the greatest risk to an occupant?

    1. A. A crumpled front bumper and a folded-up hood
    2. B. Passenger compartment intrusion of 14 inches
    3. C. Rear bumper pushed in by about 3 inches
    4. D. A cracked rear passenger door window
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    Answer: B. Passenger compartment intrusion of 14 inches

    Intrusion over 12 inches at an occupant site is a high-risk mechanism, because the occupant's space has been invaded. A crumpled hood means the crumple zone absorbed energy as designed.

24. A sedan was struck in a rear-end collision and is stopped in traffic. The driver says her headrest was set at the level of her neck. She is most at risk for:

    1. A. Chest injury from the steering wheel
    2. B. Femur fracture from the dashboard
    3. C. Bladder rupture from the seat belt
    4. D. Cervical hyperextension injury
    Show answer

    Answer: D. Cervical hyperextension injury

    A low headrest acts as a fulcrum for the head to snap backward over it. The steering wheel and dashboard are frontal-impact injuries, unlikely when stopped and struck from behind.

25. An occupant was partly ejected through a side window in a rollover. Even if he looks well, you should:

    1. A. Transport him to a trauma center per triage
    2. B. Release him if he has normal vital signs
    3. C. Transport him to the nearest clinic for x-rays
    4. D. Evaluate him further if he complains of pain
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    Answer: A. Transport him to a trauma center per triage

    Partial or complete ejection is a yellow (moderate-risk) mechanism criterion in the 2021 National Guideline for the Field Triage of Injured Patients, so the patient should go to a trauma center even if he looks well. Normal initial vital signs do not exclude serious injury, and waiting for him to complain of pain risks missing a hidden injury.