What is the space called between the lungs and the chest wall?

• A. Pleural space
• B. Thoracic cavity
• C. Mediastinal space
• D. Peritoneal space

Answer: (A)

Understanding the pleural space and its role in breathing. The space between the lungs and the chest wall is the pleural space. It’s formed by two layers of pleura—the visceral pleura covering the lungs and the parietal pleura lining the chest wall. Normally it contains only a small amount of lubricating fluid, which lets the lungs glide smoothly during respiration. The pressure in this space stays negative relative to the air, helping keep the lungs inflated. If air enters the space (pneumothorax) or fluid accumulates (pleural effusion), breathing can become difficult because the lung may collapse or be restricted. The thoracic cavity is the overall chest cavity that houses the lungs and heart; the mediastinal space is the central compartment within the chest; the peritoneal space lies in the abdominal cavity, not in the chest.