The parietal pleura is a thin membrane that lines the inner surface of the chest wall and covers the diaphragm. It is part of the pleura, which consists of two layers: the parietal pleura and the visceral pleura. The parietal pleura helps protect the lungs and provides a smooth surface for lung movement during breathing. This membrane is sensitive to pain and can be affected by various conditions, such as infections or inflammation. The space between the parietal pleura and the visceral pleura is known as the pleural cavity, which contains a small amount of fluid that reduces friction during respiration.