The<unk> ,<unk>  space, or interpleural space, is the potential space between the<unk>  of the<unk>  sac that surrounds each lung. A small amount of serous<unk>  fluid is maintained in the<unk>  to enable lubrication between the membranes, and also to create a pressure gradient. The serous membrane that covers the surface of the lung is the visceral<unk> and is separated from the outer membrane the parietal<unk> by just the film of<unk>  fluid in the<unk> . The visceral<unk> follows the fissures of the lung and the root of the lung structures. The parietal<unk> is attached to the mediastinum, the upper surface of the diaphragm, and to the inside of the ribcage.
Pleural cavity
Lung cavity
Indium lung
Endobronchial valve
Thoracic inlet
Pulmonary bay
Thoracic diaphragm
Subclavian loop