TNCC Kinematics and Mechanism of Injury 2

Question 1

An unrestrained driver slides down and under the dashboard in a frontal collision. Which injury pattern is most expected?

Accepted Answer

Posterior hip dislocation and femur or knee fractures

Answer

The down-and-under path drives the knees into the dashboard, transmitting force up the femur to the hip.

Question 2

An unrestrained driver travels up and over the steering wheel. Which finding most strongly suggests significant chest injury?

Accepted Answer

A deformed steering wheel

Answer

A bent steering wheel shows the chest absorbed major energy, raising suspicion for rib fractures, pulmonary contusion, and cardiac injury.

Question 3

A restrained driver with a lap belt worn high across the abdomen is most at risk for which injury?

Accepted Answer

Lumbar flexion-distraction (Chance) fracture with bowel injury

Answer

A high lap belt acts as a fulcrum, flexing the spine over it and injuring the lumbar vertebrae and hollow viscera.

Question 4

A vehicle is struck from behind at high speed. Without a properly positioned head restraint, which injury mechanism is most likely?

Accepted Answer

Cervical hyperextension followed by flexion

Answer

The torso is accelerated forward while the unsupported head lags backward, then snaps forward.

Question 5

A driver-side lateral (T-bone) impact occurs. Which organ injury should be of highest suspicion in the driver?

Accepted Answer

Spleen

Answer

Driver-side impacts load the left side of the body, so the spleen, left ribs, and left pelvis are at risk.

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