Pleural space

The thin potential space between the parietal and visceral pleural layers is known as the pleural space, or cavity. It normally contains a small amount of pleural fluid.

In humans, there is no anatomical connection between the left and right pleural cavities. Therefore, in cases of unilateral pneumothorax, the other lung will still function normally. However, in a unilateral tension pneumothorax, the contralateral side may be affected because of increased pressure on the lung parenchyma, blood vessels and bronchi.