While inspecting the client's chest, the nurse notes that the chest wall contracts on inspiration an...

参考答案: B

参考解析: Flail chest occurs when two or more adjacent ribs are fractured at two or more sites, resulting in a free-floating segment. This loss of chest wall stability causes respiratory impairment and notable paradoxical chest wall movement. Hemothorax or pneumothorax both decrease chest wall excursion on the affected side. A tension pneumothorax causes a mediastinal shift and tracheal deviation toward the unaffected side.