10 free EMT practice questions: Mechanism of Injury / Nature of Illness

Pelvic fracture: A pelvic fracture fits the down-and-under pathway. The knees of an unrestrained driver hit the dashboard, and the force travels up the femurs into the pelvis. With that crash you would expect damage to the dashboard or the knee bolster. In this crash the steering wheel is bent, and a bent wheel tells you the chest absorbed the impact.

Spinal cord injury: fits axial loading, where the head or neck takes the force. Diving, falls, rollovers, and ejections are examples. Nothing in this scene describes a rollover or an ejection. The damage is at the steering wheel, and a bent wheel points to the chest, not the spine.

Burn injury: You suspect burns when there is fire, smoke, or a chemical exposure on scene. This question mentions no fire or heat source. A bent steering wheel is blunt force to the chest, not a burn mechanism.

An isolated injury to the head only (scalp, skull, and face): An isolated head injury fits force that lands at one point on the skull. A falling object or a blow in an assault does that. A fall down stairs spreads the force across many parts of the body. Being alert and oriented also tells you nothing about the ribs, pelvis, or spine you have not felt yet.

Isolated fractures of the lower extremities only (ankles, tibias, and femurs): Isolated leg fractures fit a controlled feet-first fall from a height. The force travels up from the heels and breaks the heel bone, the tibia, and the lower spine. A stair fall is not a controlled landing. The patient rolls and hits with whatever part leads. Leg injuries are likely here too, and the word "only" is what makes this option wrong.

Soft-tissue injuries only, without bone involvement (bruising and abrasions): Bruises and scrapes with no broken bones fit a low-energy fall. A younger patient slipping on a flat floor from standing is one example. A fall down 12 steps carries more energy than that, and an older adult's bones handle less of it. Expecting bruises alone leads to a missed hip, rib, or spine fracture, because nobody does the exam that would find it.

External bleeding is the most reliable indicator of how serious an abdominal stab wound is: External bleeding is a fair way to judge a wound when you can see the whole depth, like an abrasion or a shallow laceration. You cannot see the depth of a stab wound. The dangerous bleeding in a stab wound to the abdomen is internal. A patient can lose a large amount of blood into the abdomen while the dressing over the wound stays nearly dry.

A small entry wound makes injury to deep organs such as the liver or spleen unlikely: A small entry wound only means the blade was narrow. A narrow blade can still easily reach the spleen from the left upper abdomen. Deep injury is no less likely with a small wound.

Stable vital signs indicate that urgent transport is unnecessary for abdominal stab wounds: Stable vital signs carry real weight for a low energy injury with no penetration. In penetrating trauma, the vital signs lag behind the injury. Compensation holds the numbers steady while the bleeding goes on. Stable vitals right now are only one moment in time. Transport priority in penetrating trauma comes from what the blade could reach, and reassessment catches the change.

Thoracic spine and rib fractures from impact to the back: Thoracic spine and rib injuries fit a fall where the patient lands flat on the back or the chest. This patient landed on the buttocks and denies back pain. The force never went into the thoracic spine.

Cervical spine injury from whiplash during the fall: Whiplash comes from the neck snapping back and forth, like in a rear-end collision. This patient dropped straight down onto the buttocks, with no head trauma and no neck pain.

Pelvic fracture and femur injury from the mechanism: Landing on a hip or on the side loads the pelvis and the femur directly. A pelvis injury is worth thinking about in any fall from a height. This patient's pain is only at the tailbone, with no pelvic tenderness mentioned. The force went up through the sacrum and the lumbar spine instead.

This is a mechanism of injury from an unwitnessed fall: A fall is a mechanism of injury. Here the patient was getting weaker for hours before the fall, and the illness caused the fall. Working this as a fall injury alone misses the illness that caused it.

This is a low-priority call because the patient is alert and speaking: Being alert does not mean a patient is stable. This patient is alert but confused, and confusion is an abnormal mental status. A patient who can talk can still be having a stroke, sepsis, or a metabolic crisis. The confusion and the weakness getting worse make this a priority call.

This requires spinal motion restriction because any fall suggests cervical trauma: Some falls do call for spinal motion restriction, like a fall from a height or a fall with loss of consciousness. Not every fall suggests a neck injury. A confused patient may not be able to tell you the neck hurts, so you still check for injuries from the fall. The weakness and confusion came first, and they make this a medical call.

The patient's complaint of hip pain is what defines this as a significant mechanism of injury: Hip pain after a side impact is a real warning sign for a pelvic fracture. A significant mechanism is defined by the crash itself, here the 18 inches of intrusion, not by a complaint. Document the hip pain as a finding.

Normal vital signs at this point rule out a significant mechanism of injury: An alert patient with normal vital signs looks stable. Normal vital signs do not rule out bleeding in the pelvis or abdomen. The body can compensate for blood loss before the heart rate or blood pressure changes. The significant mechanism criteria exist to flag that risk before the vital signs do.

Only unrestrained occupants are classified under significant mechanism of injury criteria: Unrestrained occupants are more likely to be ejected, and that is its own warning sign. Wearing a seat belt does not exempt anyone from the criteria. A restrained driver behind 18 inches of door intrusion still has a significant mechanism of injury.

Facial and cervical spine injury from contact with the windshield: Windshield contact is the up-and-over path, where the head and face hit the glass. Here the windshield is intact and undamaged, so the head never hit the windshield.

Abdominal organ injury from contact with the steering wheel: The steering wheel causes chest and abdominal injuries in a frontal crash. This patient was the front-seat passenger. There is no steering wheel in front of the passenger seat.

Lateral chest injury from contact with the door and door post: A side impact or a rollover against the door is going to give you a lateral chest injury. This crash was head-on, and both front doors are intact and undamaged.

Head and cervical spine injury from lateral bending away from the impact: Bending away from the impact sounds right, because the car rocks away from the impact. The rocking car is what throws the driver's head and shoulders the other way, toward the intruding truck. The head hits the door post or the window.

Facial and anterior chest injury from forward deceleration: Facial and chest injury from forward deceleration is the pattern for a frontal crash. This crash was a square side impact. The windshield and the steering wheel are undamaged, so the driver never hit anything in front.

Thoracic spine injury from axial loading through the seat: Axial loading injures the spine when force runs along its length, like a fall onto the feet or a dive into shallow water. This was a side impact, with the force coming in sideways. The roof is undamaged, so nothing pushed down on the spine.

The first driver, because doubling the weight quadruples the energy: The quadrupling in B belongs to speed, not weight. Weight counts in direct proportion, so doubling the weight only doubles the energy. Doubling the speed is what makes the energy four times as large.

Neither driver, because the doubled speed and halved weight cancel out: Half the weight at double the speed looks like an even trade. The trade would only be even if speed counted the same way weight does. Doubling the speed multiplies the energy by four, and halving the weight only cuts the energy in half. The lighter, faster car still ends up with more energy.

The first driver, because more weight means more energy to absorb: A heavier car feels more dangerous, and weight is part of the energy. Weight counts in direct proportion, while speed is squared. The driver's own energy comes from how fast the body was moving, not from the weight of the car around it.

Wrist injury, because a falling child extends the arms to break the fall: Catching yourself on an outstretched hand is what adults do, and a wrist fracture is the classic adult injury from a low fall. A toddler's head is much heavier for the body than an adult's. The heavy head hits the ground before the hands can catch the fall.

Ankle and knee injury, because the legs absorb the energy of a short fall: A feet-first landing does load the legs. The energy travels up through the heel bone (calcaneus), the pelvis, and the spine. That pattern fits a patient who lands on the feet. A top-heavy toddler going over an edge lands head first instead.

Clavicle injury, because the shoulder takes the first impact in a low fall: A clavicle fracture is common in children. A broken clavicle comes from a fall onto the shoulder or an outstretched arm. A toddler's body proportions make the head lead the fall instead.