Chest Wall Injuries: Rib Fractures, Flail Chest, Sternal Fracture, and Pulmonary Contusion Practice Questions

25 multiple-choice questions on Chest wall injuries: rib fractures, flail chest, sternal fracture, and pulmonary contusion for paramedic and EMT students, from Chapter 36 (Chest Trauma). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. A flail chest is defined as:

   1. A. A single rib broken in three or more separate places
   2. B. Two or more adjacent ribs broken in two or more places
   3. C. Three or more ribs broken at any point on one side
   4. D. Any rib fracture that also tears through the parietal pleura
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   Answer: B. Two or more adjacent ribs broken in two or more places

   A flail segment needs at least two adjacent ribs each broken in at least two places, so that piece of chest wall floats free. Several ribs each broken once is serious but does not create a free-floating segment.

2. During spontaneous inspiration, a flail segment typically:

   1. A. Moves inward
   2. B. Moves outward
   3. C. Moves with the chest
   4. D. Bulges with each heartbeat
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   Answer: A. Moves inward

   The free segment is sucked in by negative intrathoracic pressure while the rest of the chest expands, which is paradoxical motion. Moving with the chest is normal motion and would mean the segment is not flail or is being splinted.

3. In a patient with flail chest, the main cause of hypoxia is usually:

   1. A. The paradoxical motion of the segment
   2. B. Loss of phrenic nerve function
   3. C. Blood loss from the fractured ribs
   4. D. The underlying pulmonary contusion
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   Answer: D. The underlying pulmonary contusion

   The force needed to create a flail segment almost always bruises the lung underneath, and the contusion causes shunting. Paradoxical motion is the striking finding, but it contributes less to hypoxia than the lung injury does.

4. A 68-year-old man in a frontal crash has a right-sided flail segment. He is breathing 34 times/min and shallowly, with an SpO2 of 84% on a nonrebreather mask. The best intervention is to:

   1. A. Place a sandbag against the flail segment
   2. B. Wrap the chest snugly with a cravat binder
   3. C. Assist ventilations with positive pressure
   4. D. Position him lying on the uninjured side
   Show answer

   Answer: C. Assist ventilations with positive pressure

   Positive pressure splints the flail segment from inside and improves oxygenation of the contused lung. Sandbags and binders restrict chest expansion and worsen hypoventilation.

5. A 40-year-old woman has two isolated rib fractures after a fall. Her SpO2 is 96%, and she rates her pain 8/10. The most appropriate care is to:

   1. A. Tape the chest wall to limit motion
   2. B. Bind the chest with a firm swathe
   3. C. Withhold analgesia to protect her drive
   4. D. Give analgesia and coach deep breaths
   Show answer

   Answer: D. Give analgesia and coach deep breaths

   Pain control lets the patient breathe deeply and cough, which prevents atelectasis and pneumonia. Taping or binding the chest limits expansion and causes the very hypoventilation you are trying to prevent.

6. A 35-year-old motorcyclist who struck a guardrail has fractures of the first and second ribs. This finding suggests:

   1. A. High-energy force and possible great vessel injury
   2. B. Low-energy force such as a simple fall from standing
   3. C. Likely injury to the liver or spleen underneath
   4. D. Brittle bones rather than significant force
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   Answer: A. High-energy force and possible great vessel injury

   The upper ribs are short, thick, and protected by the shoulder girdle, so breaking them takes great force, and the subclavian vessels and aorta lie close by. Liver and spleen injuries are associated with lower rib fractures, not upper ones.

7. A patient localizes pain to one spot on the lateral chest, and you feel a grating sensation under your fingers as he breathes. This finding is called:

   1. A. Pleural friction rub
   2. B. Bony crepitus
   3. C. Pulsus paradoxus
   4. D. Tactile fremitus
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   Answer: B. Bony crepitus

   Crepitus is the grating of broken bone ends and supports a rib fracture. A pleural friction rub is a sound heard with a stethoscope, not a grating felt over a point of tenderness.

8. After a steering wheel impact, a driver has tenderness and a palpable step-off over the sternum. Which associated injury should you most suspect?

   1. A. Blunt cardiac injury
   2. B. Spontaneous pneumothorax
   3. C. Diaphragmatic rupture
   4. D. Tracheal transection
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   Answer: A. Blunt cardiac injury

   The heart lies directly behind the sternum, so the force that fractures it often bruises the myocardium; continuous ECG monitoring is needed. A spontaneous pneumothorax occurs without trauma, so it is not linked to a sternal blow.

9. Pulmonary contusion is best described as:

   1. A. Collapse of the lung from air in the pleural space
   2. B. Blood collecting between the two pleural layers
   3. C. Air leaking from a torn bronchus into the mediastinal space
   4. D. Bruising of lung tissue with bleeding into the alveoli
   Show answer

   Answer: D. Bruising of lung tissue with bleeding into the alveoli

   In a contusion, blood and fluid leak into alveoli and interstitium, impairing gas exchange. Blood between the pleural layers is a hemothorax, a separate injury that can occur alongside a contusion.

10. The signs and symptoms of pulmonary contusion typically:

    1. A. Appear and peak within minutes
    2. B. Resolve within the first hour
    3. C. Worsen over the first 24 hours
    4. D. Do not appear for 3 to 5 days
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    Answer: C. Worsen over the first 24 hours

    Edema and bleeding in the lung increase over hours, so a patient who looks well at the scene may become hypoxic later. Expecting the injury to peak immediately leads to under-triage and too little reassessment.

11. A 30-year-old with a suspected pulmonary contusion has a BP of 118/76 mmHg and a heart rate of 96 beats/min. The best fluid strategy is to:

    1. A. Give a 2-L bolus to keep the injured lungs perfused
    2. B. Give IV fluid judiciously to avoid lung edema
    3. C. Give a diuretic to dry out the injured lung
    4. D. Withhold IV access until hospital arrival
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    Answer: B. Give IV fluid judiciously to avoid lung edema

    Bruised lung leaks fluid easily, so large volumes worsen edema and hypoxia; give only what is needed to maintain perfusion. Diuretics are not a prehospital treatment for contusion and can worsen hypovolemia from other injuries.

12. A 45-year-old ejected from a vehicle has a section of the left chest that moves in while the rest of the chest moves out. This finding indicates:

    1. A. A flail segment
    2. B. A sternal fracture
    3. C. A tension pneumothorax
    4. D. A simple rib fracture
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    Answer: A. A flail segment

    Paradoxical motion of part of the chest wall is the hallmark of a flail segment. A simple rib fracture is painful but stays attached to the chest wall and moves normally.

13. Paradoxical motion may not be visible right after the injury because:

    1. A. The contusion pushes the segment out
    2. B. The intact pleura holds the segment still
    3. C. Muscle spasm splints the flail segment
    4. D. Hypoxia relaxes the intercostal muscles
    Show answer

    Answer: C. Muscle spasm splints the flail segment

    Spasm of the chest wall muscles can hold the segment in place early, and the paradoxical motion appears as the muscles fatigue. A contusion is in the lung, not the wall, and does not push the segment outward.

14. When you begin positive-pressure ventilation for a patient with flail chest, you should watch closely for:

    1. A. Worsening of the paradoxical chest wall motion
    2. B. Bradycardia from vagal stimulation
    3. C. Outward displacement of the ribs
    4. D. Development of a tension pneumothorax
    Show answer

    Answer: D. Development of a tension pneumothorax

    Broken rib ends often tear the lung, and positive pressure can push air through that tear into the pleural space faster than it can leave. Positive pressure reduces paradoxical motion rather than worsening it.

15. An 80-kg patient with painful rib fractures has a BP of 128/80 mmHg and adequate breathing. Using fentanyl 1 mcg/kg, an appropriate initial IV dose is:

    1. A. 8 mcg
    2. B. 80 mcg
    3. C. 800 mcg
    4. D. 250 mcg
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    Answer: B. 80 mcg

    At 1 mcg/kg, an 80-kg adult receives 80 mcg, titrated in repeat doses for pain. 800 mcg is a tenfold error that would cause apnea; dosing and maximums vary by protocol.

16. Before giving opioid analgesia to a patient with rib fractures, you should confirm that the patient:

    1. A. Has had a chest radiograph taken
    2. B. Has rated his pain at least 8 on a 10-point scale
    3. C. Has an adequate BP and respiratory effort
    4. D. Has had a 12-lead ECG recorded
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    Answer: C. Has an adequate BP and respiratory effort

    Opioids can lower blood pressure and depress breathing, so hemodynamic and ventilatory status must be adequate first. A radiograph or a 12-lead ECG is not needed to treat pain in the field, and analgesia is not reserved for patients above a particular pain score.

17. Fractured rib ends most often injure the:

    1. A. Esophagus and thoracic duct behind them
    2. B. Aortic arch and pulmonary trunk above
    3. C. Trachea and bronchi in the mediastinum
    4. D. Underlying lung and intercostal vessels
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    Answer: D. Underlying lung and intercostal vessels

    Sharp rib fragments tear the pleura, lung, and intercostal vessels next to them, causing pneumothorax and hemothorax. The esophagus and great vessels lie deep in the mediastinum, away from most rib fractures.

18. A sternal fracture most often results from:

    1. A. A direct blow to the anterior chest
    2. B. A fall onto an outstretched hand
    3. C. A lateral impact to the shoulder
    4. D. A blast wave in an open area
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    Answer: A. A direct blow to the anterior chest

    Steering wheel and dashboard impacts deliver direct anterior force that fractures the sternum. A fall on an outstretched hand transmits force to the clavicle and arm, not the sternum.

19. A patient with a chest injury coughs up bright red blood. This is called:

    1. A. Hematemesis
    2. B. Hemoptysis
    3. C. Hemothorax
    4. D. Epistaxis
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    Answer: B. Hemoptysis

    Hemoptysis is blood coughed up from the airway or lung and suggests a contusion or airway injury. Hematemesis is vomited blood from the GI tract, which is the common mix-up.

20. A 30-year-old woman hit her chest on the steering wheel. She has dyspnea, crackles over a bruised area, and an SpO2 of 89%. Breath sounds are present bilaterally, the trachea is midline, and her BP is 124/78 mmHg. The most likely injury is:

    1. A. Tension pneumothorax
    2. B. Pulmonary contusion
    3. C. Massive hemothorax
    4. D. Cardiac tamponade
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    Answer: B. Pulmonary contusion

    Hypoxia with crackles over the impact site and preserved breath sounds fits fluid-filled, bruised lung. A tension pneumothorax would cause absent breath sounds and signs of shock, which she does not have.

21. A flail sternum occurs when:

    1. A. The sternum breaks away from the clavicles
    2. B. The xiphoid process fractures and floats
    3. C. Ribs fracture on both sides of the sternum
    4. D. One rib separates from its cartilage
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    Answer: C. Ribs fracture on both sides of the sternum

    Fractures or costochondral separations on both sides let the whole sternum move paradoxically. A single costochondral separation is painful but does not create a free-floating segment.

22. The most common potentially life-threatening chest injury in blunt trauma is:

    1. A. Pulmonary contusion
    2. B. Cardiac tamponade
    3. C. Aortic disruption
    4. D. Diaphragmatic rupture
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    Answer: A. Pulmonary contusion

    Pulmonary contusion is very common after significant blunt chest impact and can progress to respiratory failure. Tamponade is more typical of penetrating trauma and is less common after blunt force.

23. CPAP may help a conscious patient with flail chest or pulmonary contusion, but it should be avoided if the patient has:

    1. A. An SpO2 of 92% with mild dyspnea at rest
    2. B. A respiratory rate of 24 breaths/min
    3. C. Pain that improves with analgesia
    4. D. Hypotension or a suspected pneumothorax
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    Answer: D. Hypotension or a suspected pneumothorax

    CPAP raises intrathoracic pressure, which lowers venous return and can enlarge a pneumothorax into a tension pneumothorax. Mild hypoxia and tachypnea are reasons to consider CPAP, not reasons to withhold it.

24. Which finding suggests impending respiratory failure in a patient with multiple rib fractures?

    1. A. Faster respirations with a rising SpO2
    2. B. Increasing anxiety with good air movement throughout
    3. C. Slowing respirations and decreasing alertness
    4. D. Speaking in full sentences despite pain
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    Answer: C. Slowing respirations and decreasing alertness

    A tiring patient breathes slower and becomes drowsy as CO2 rises, which signals the need for assisted ventilation. Anxiety with good air movement is a compensating patient, not a failing one.

25. When CPAP is used for a patient with a pulmonary contusion, a typical starting pressure is:

    1. A. 5 to 10 cm H2O
    2. B. 1 to 2 cm H2O
    3. C. 20 to 25 cm H2O
    4. D. 30 to 40 cm H2O
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    Answer: A. 5 to 10 cm H2O

    CPAP is usually started at about 5 cm H2O and titrated up to about 10 cm H2O to recruit alveoli. Pressures of 20 cm H2O or more greatly reduce venous return and raise the risk of barotrauma.