SkillsUSA First Aid & CPR Practice Test

Flail chest happens when multiple adjacent ribs are fractured in two places, creating a free-floating segment of chest wall. That unstable section moves paradoxically with breathing—moving inward as the rest of the chest expands and outward as it recoils—which disrupts normal ventilation and leads to poor air exchange. The description that multiple ribs are broken and the chest cannot expand properly captures this loss of chest-wall stability and the resulting breathing difficulty.

Bruising or a single rib fracture don’t produce the unstable, paradoxical movement that defines a flail segment, and a chest that “collapses completely” describes a more extreme or different scenario than flail chest. In a real incident, treat this as a medical emergency: ensure airway and breathing, call for help, and provide oxygen if available while monitoring the person.