What cavity in the chest is filled by PTX/HTX?

The correct answer is the intrapleural space. The intrapleural space refers to the potential space between the two pleurae of the lungs—the visceral pleura that covers the lungs and the parietal pleura that lines the thoracic cavity. This space is normally filled with pleural fluid, which reduces friction between the lungs and the chest wall during respiration.

When conditions such as a pneumothorax (PTX) or hemothorax (HTX) occur, air (in the case of pneumothorax) or blood (in the case of hemothorax) can accumulate in this intrapleural space. This accumulation can lead to pressure on the lung, potentially causing it to collapse, which is a medical emergency.

The other options refer to different anatomical spaces. The pericardial space is the cavity surrounding the heart, which can be affected by fluid accumulation but is not directly related to pneumothorax or hemothorax. The pleural space is often mistakenly referenced interchangeably with the intrapleural space, but it usually encompasses the entire section where the pleura exist. The abdominal cavity refers to the area containing various abdominal organs and is not related to lung conditions