Pleural Space

The pleural space is a thin, fluid-filled gap between the two layers of tissue that surround each lung—the visceral pleura (attached to the lung) and the parietal pleura (lining the chest wall). Its main function is to allow smooth movement of the lungs during breathing and reduce friction. Normally, only a small amount of fluid exists here. If excess fluid or air accumulates—due to injury, infection, or other conditions—it can impair lung expansion and breathing, leading to discomfort or difficulty breathing.