Covering of the lungs is called pleural membrane.Each Lung is enclosed of a double membrane called pleurae. The outer covering adheres to chest wall and diaphragm and is known as parietal pleura and the inner covering membrane which closely covers the lung is called visceral pleura. The narrow space between the two membranes is filled with water fluid,called pleural fluid that acts as cushion to the lungs during any type of shock or damage.