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

Pelvic fracture: points you toward the down-and-under pathway, where an unrestrained driver's knees slam the dashboard and force travels up the femurs into the pelvis, something you'd expect with dashboard intrusion or knee-bolster damage, not a bent wheel. The finding here is steering wheel deformity, which tells you the chest absorbed the impact, not the knees or pelvis.

Spinal cord injury: fits axial loading mechanisms like diving, falls, rollover, or ejection, where the head or neck takes the force. Nothing in this scene describes a rollover or ejection; the deformity is confined to the steering wheel, which implicates the chest, not the spine.

Burn injury: suspicion comes from fire, smoke, or chemical exposure at the scene, not blunt deformity of interior components. A bent steering wheel is evidence of blunt force transfer to the chest, with no mention of fire or heat source anywhere in this scenario.

An isolated injury to the head only (scalp, skull, and face): An isolated head injury is what you predict when all the energy lands at one point on the skull: a falling object, or a blunt assault. A tumbling stair fall spreads that energy across several surfaces instead. The alert-and-oriented detail is also the part that leads crews to under-triage this mechanism; a normal mental status says nothing about the ribs, pelvis, or spine you have not palpated yet.

Isolated fractures of the lower extremities only (ankles, tibias, and femurs): Isolated lower-extremity fracture is the pattern for a controlled feet-first fall from height, where force travels up the axial skeleton from the heels and produces the calcaneus, tibia, and lumbar spine injuries that go with it. A stair fall is not a controlled landing; the patient rotates and strikes with whatever leads. Lower-extremity injury is genuinely likely here, so what makes the option wrong is the word only.

Soft-tissue injuries only, without bone involvement (bruising and abrasions): Soft-tissue injury with no bone involvement describes a low-energy event, like a slip onto a flat floor from standing in a younger patient. Twelve steps carries more energy than that, and an older adult's skeleton tolerates less of it. Expecting bruising alone is how a hip, rib, or spinal fracture gets missed, because you never perform the palpation that would have found it.

External bleeding is the most reliable indicator of how serious an abdominal stab wound is: External bleeding is a fair severity gauge for a wound whose full depth you can actually see: an abrasion, a shallow laceration. A stab wound never qualifies, because the dangerous bleeding in penetrating abdominal trauma is internal: a patient can lose a large volume into the abdominal cavity while the dressing over the wound stays nearly dry, so the wound that looks quietest on the outside can belong to the sickest patient on scene.

A small entry wound makes injury to deep organs such as the liver or spleen unlikely: This is the same error dressed up as anatomy. Entry size reflects how wide the blade was, not how far it went, and a narrow blade reaches the spleen from the left upper abdomen without difficulty. A small wound is evidence about the weapon, not evidence about the organs, and it makes deep injury no less likely.

Stable vital signs indicate that urgent transport is unnecessary for abdominal stab wounds: Stable vital signs carry real weight in a low-energy, non-penetrating complaint. In penetrating trauma they lag the injury, because compensation holds the numbers steady while bleeding continues, so 'currently stable' is one frame of a movie. Transport priority in penetrating trauma is set by what the mechanism can reach, and the reassessment is what catches the change.

Thoracic spine and rib fractures from impact to the back: This fits a fall where the patient lands flat on the back or chest, transmitting force into the thoracic cage and ribs. Here the patient landed on the buttocks and denies back pain, so the force path never loads the thoracic spine.

Cervical spine injury from whiplash during the fall: Whiplash comes from a sudden hyperextension-flexion motion of the neck, typical of rear-end collisions, not a straight vertical drop onto the buttocks with no head trauma or neck pain reported.

Pelvic fracture and femur injury from the mechanism: A fall onto the hip or a side-first landing loads the pelvis and femur directly, and this mechanism deserves consideration any time someone drops from height. This patient's pain is localized to the tailbone with no pelvic tenderness mentioned, so the axial force here is concentrating on the sacrum and lumbar spine instead.

This is a mechanism of injury from an unwitnessed fall: A fall is a genuine mechanism of injury when someone trips or is struck by an external force, and that drives your trauma survey. Here the weakness and confusion started hours before the patient hit the bed, so the fall is the effect of the illness, not the cause, reversing that sequence.

This is a low-priority call because the patient is alert and speaking: An alert patient can still be critically ill, and alert but confused is itself an abnormal mental status, not a reassuring one. Speaking does not rule out stroke, sepsis, or a metabolic crisis, so priority here is set by the altered mentation and progressive weakness, not by the ability to talk.

This requires spinal motion restriction because any fall suggests cervical trauma: High-risk falls, from height, with loss of consciousness, or with suspected axial trauma, do call for spinal motion restriction. This patient has no evidence of trauma to the head, chest, or extremities, and fell only after becoming weak and confused, so the fall itself carries no mechanism to protect the spine against.

The patient's complaint of hip pain is what defines this as a significant mechanism of injury: A focal complaint like hip pain feels like the clue driving the decision, and pelvic pain after a side impact is a genuine red flag for fracture, but significant MOI is defined by the mechanism itself, the 18 inches of intrusion, not by any specific complaint; hip pain is a finding to document, not the criterion that classifies this crash.

Normal vital signs at this point rule out a significant mechanism of injury: A patient who is alert and oriented with normal vitals looks stable, which feels like a reason to downgrade the mechanism, but normal vitals do not rule out serious pelvic or abdominal hemorrhage, since compensation can mask blood loss before heart rate or blood pressure change. Significant-MOI criteria exist to flag risk before vitals do, not to be overridden by them.

Only unrestrained occupants are classified under significant mechanism of injury criteria: Unrestrained occupants do carry higher ejection risk and are a separate red flag, but restraint status doesn't exempt anyone from significant-MOI criteria; a restrained driver behind 18 inches of door intrusion still meets the standard because the criterion is the intrusion itself, not who was buckled.

Facial and cervical spine injury from contact with the windshield: The up-and-over path is the frontal-crash pattern most often pictured, in which the head and face strike the windshield. The question states the windshield is intact and undamaged, so no head contact occurred there.

Abdominal organ injury from contact with the steering wheel: Striking the steering wheel is the classic frontal-crash chest and abdominal mechanism. This patient was the front-seat passenger, and there is no steering wheel in front of the passenger seat.

Lateral chest injury from contact with the door and door post: Lateral chest injury is the injury pattern for a side impact and for a rollover against the door. The question describes a head-on impact and states that both front doors are intact and undamaged.

Head and cervical spine injury from lateral bending away from the impact: The occupant seems like they should be flung away from the side that was struck. The vehicle does rock away from the impact, but that is exactly what whips the occupant's shoulders and head toward the intruding vehicle, driving the skull against the door post or the window.

Facial and anterior chest injury from forward deceleration: Facial and chest injury from forward deceleration is the most-drilled frontal-crash pattern. The question describes a square side impact and states the windshield and steering wheel are undamaged, so no forward contact occurred.

Thoracic spine injury from axial loading through the seat: Axial loading is a real spinal mechanism, from a fall onto the feet or a dive into shallow water. It requires force along the length of the spine; the question describes a horizontal side impact with the roof undamaged, so there was no vertical load.

The first driver, because doubling the weight quadruples the energy: The kinetic energy relationship is not even-handed, but this attaches the squaring to the wrong variable. Weight contributes in direct proportion, so doubling it only doubles the energy; it is speed that is squared.

Neither driver, because the doubled speed and halved weight cancel out: The two vehicles look like an even trade of weight for speed. It would be an even trade only if speed contributed in direct proportion, the way weight does. Doubling the speed multiplies the energy by four while halving the weight only cuts it in half, so the trade is not even.

The first driver, because more weight means more energy to absorb: Heavier feels more dangerous, and weight really is part of the relationship. Weight matters, but it contributes in direct proportion while speed is squared, and the occupant's own energy comes from the speed the body was traveling rather than from the weight of the vehicle around it.

Wrist injury, because a falling child extends the arms to break the fall: Catching yourself on an outstretched hand is the adult reflex, and wrist fracture is the classic adult low-fall injury. A toddler's head is proportionally much heavier than an adult's, so the head, not the hands, arrives first.

Ankle and knee injury, because the legs absorb the energy of a short fall: A feet-first landing does load the legs, transmitting energy through the calcaneus, the pelvis, and the spine. That applies to a patient who lands on the feet; a top-heavy toddler going over an edge does not.

Clavicle injury, because the shoulder takes the first impact in a low fall: Clavicle fracture is a common pediatric injury and is easy to attach to any fall. It follows a fall onto the shoulder or the outstretched arm, not the head-leading fall a toddler's body proportions produce.