Which condition increases chest wall compliance?

Which condition increases chest wall compliance?

• A. Morbid obesity
• B. Kyphoscoliosis
• C. Flail chest injuries
• D. Chest-wall edema

Answer: (C)

Chest wall compliance reflects how easily the rib cage can expand during breathing. In a flail chest, several adjacent ribs are fractured in more than one place, creating a free-floating segment. That segment loses the normal rib cage rigidity and moves with less resistance as intrathoracic pressure changes, effectively increasing the chest wall’s distensibility. So the chest wall becomes more compliant overall, even though the condition causes paradoxical movement that can impair ventilation. In contrast, factors like morbid obesity tend to limit chest expansion, kyphoscoliosis stiffens the chest wall, and chest-wall edema adds mass and resistance, all reducing compliance.

Chest wall compliance reflects how easily the rib cage can expand during breathing. In a flail chest, several adjacent ribs are fractured in more than one place, creating a free-floating segment. That segment loses the normal rib cage rigidity and moves with less resistance as intrathoracic pressure changes, effectively increasing the chest wall’s distensibility. So the chest wall becomes more compliant overall, even though the condition causes paradoxical movement that can impair ventilation.

In contrast, factors like morbid obesity tend to limit chest expansion, kyphoscoliosis stiffens the chest wall, and chest-wall edema adds mass and resistance, all reducing compliance.