BCEN CEN Practice Question

The correct answer is flail chest. Flail chest is a life-threatening injury that occurs when three or more consecutive ribs are fractured in two or more places, creating a free-floating segment of the chest wall. The hallmark clinical sign of flail chest is paradoxical chest wall motion, where the detached segment moves inward during inspiration and outward during expiration, opposite to the movement of the rest of the thoracic cage. This paradoxical movement impairs ventilation and can lead to respiratory failure. A simple pneumothorax involves air in the pleural space causing lung collapse but does not cause paradoxical motion. A tension pneumothorax involves a progressive buildup of air, leading to mediastinal shift and cardiovascular collapse, with signs like tracheal deviation and profound hypotension, but not typically paradoxical motion. Pulmonary contusion is bruising of the lung tissue, which can cause hypoxemia and respiratory distress, but it does not produce the characteristic chest wall movement of a flail chest, although it often occurs concurrently.