Here's why:

* Parietal membranes line the cavities of the body.

* Pleura refers to the membranes that surround the lungs.

* Parietal pleura specifically lines the chest cavity (thoracic cavity), creating a space for the lungs to expand and contract.

To further illustrate:

Imagine a balloon inside a box. The balloon is the lung, and the box is the chest cavity. The parietal pleura would be the lining of the box, while the visceral pleura (the other part of the pleural membrane) would be the lining of the balloon.

Let me know if you'd like to know more about other parietal membranes or the different types of serous membranes!