What term describes an abnormal chest movement where part of the chest wall moves in the opposite direction during breathing?

The term that describes an abnormal chest movement where part of the chest wall moves in the opposite direction during breathing is known as paradoxical chest movement. This phenomenon occurs when there is a disruption in the normal functioning of the chest wall, often due to an injury such as a flail chest, where a segment of the rib cage becomes detached due to multiple fractures.

During inhalation, instead of the affected segment moving outward as the lungs expand, it moves inward, which can compromise respiratory function and significantly affect ventilation. Recognizing this sign is critical for EMTs, as it may indicate severe underlying injuries that require immediate medical intervention.

In contrast, asymmetrical chest movement refers to a situation where one side of the chest moves differently from the other but not necessarily in opposite directions. Other terms like hyperventilation involve the rate of breathing rather than the mechanics of chest wall movement, and costal retraction refers to a visual cue seen typically in distress or obstructive conditions, but it does not specifically denote the inverse movement characteristic of paradoxical movement. Thus, paradoxical chest movement accurately captures the abnormality described in the question.