What condition involves the collection of air and gas in the pleural cavity?

The condition that involves the collection of air and gas in the pleural cavity is pneumothorax. This occurs when air leaks into the space between the lung and the chest wall, which can happen due to a variety of reasons, including trauma, lung disease, or spontaneously without any apparent cause. The presence of air in this space can cause the lung to collapse, leading to symptoms such as sudden chest pain and shortness of breath.

Understanding the specific nature of pneumothorax is crucial because it directly affects the management and treatment options. This condition often requires immediate medical attention, which may include the insertion of a chest tube or other interventions to remove the air and allow the lung to re-expand.