55 Pleura

What are the pleura?

The pleura refers to two sets of membranes which line respiratory structures in the thoracic cage. Imagine punching your fist into a balloon without popping it. Just like the abdominal perineum, the pleura is like an inflated balloon which encompasses the lungs.

There are two sets of pleura:

• The parietal pleura like the outer layer of the balloon (not touching your fist/ribcage), lines the inside of the thoracic cage, including the rib cage and diaphragm.

• The visceral pleura like the inner layer of the balloon (directly touching your fist/lung)  lines the outside of the lung.

Between the parietal and visceral pleura is the interpleural space which is crucial for maintaining different levels of pressure. The interpleural space also contains a small amount of serous fluid, which acts as a lubricant, allowing the pleural membranes to slide smoothly over each other without friction during respiration

Figure 111 Anterior view of the pleura