What is visceral pleura cavity?

The lungs are surrounded by two membranes, the pleura. The outer pleura is attached to the chest wall and is known as the parietal pleura; the inner one is attached to the lung and other visceral tissues and is known as the visceral pleura. In between the two is a thin space known as the pleural cavity or pleural space. It is filled with pleural fluid, a serous fluid produced by the pleura. The pleural fluid lubricates the pleural surfaces and allows the layers of pleura to slide against each other easily during respiration. It also provides the surface tension that keeps the lung surface in contact with the chest wall. During quiet breathing, the cavity normally experiences a negative pressure (compared to the atmosphere) which helps adhere the lungs to the chest wall, so that movements of the chest wall during breathing are coupled closely to movements of the lungs. See the related link for more information.