Which term defines trauma to the chest involving multiple rib fractures with free-floating segments?

• A. Flail chest
• B. Failure to feed
• C. Evasion
• D. Express consent

Answer: (A)

Flail chest occurs when blunt chest trauma causes two or more adjacent ribs to fracture in two or more places, creating a segment that becomes detached from the rest of the chest wall. That free-floating segment moves paradoxically during breathing—moving inward on inspiration and outward on expiration—destabilizing the chest and markedly impairing ventilation. This disruption of chest wall mechanics is what defines a flail chest and explains the respiratory distress and potential for poor oxygenation. The other terms do not describe chest injuries: failure to feed refers to feeding problems, evasion is a non-medical term, and express consent is a legal/administrative concept.