Paradoxical chest motion refers to:

• A. The entire chest moving outward during inhalation
• B. The chest wall moving only with abdominal muscles
• C. The chest rising evenly during all breaths
• D. Part of the chest moves inward during inhalation while another part moves outward during exhalation

Answer: (D)

Paradoxical chest motion happens when a portion of the chest wall moves opposite to the rest of the chest during breathing. This usually occurs with a flail chest, where several ribs are fractured and a segment becomes detached from the surrounding chest wall. During inhalation, the intact chest expands outward while the free segment moves inward due to the negative intrathoracic pressure. During exhalation, the pressure reverses and the free segment moves outward while the rest of the chest relaxes, so that part of the chest is bulging outward when the rest is contracting inward. This opposite movement is what defines paradoxical motion.

This finding signals significant chest trauma and can lead to poor ventilation and gas exchange, so rapid assessment and supportive care are essential—ensuring airway and oxygenation, and considering stabilization of the chest wall or ventilatory support as indicated. In contrast, normal chest expansion or abdominal-dominant breathing patterns do not show this opposing movement.