For non-medical professionals, the concept of pleura may be rather abstract. The pleura is a thin, smooth membrane that covers the surface of the lung and the inner surface of the chest wall. The membrane covering the surface of the lung is called the dirty pleura, and the pleura covering the inside of the chest wall is called the wall pleura, and the cavity formed by the mutual migration between these two layers of pleura is called the pleural cavity. The normal pleural cavity has a little liquid in it and the cavity is under negative pressure, which is important to maintain the lung reopening. If gas or liquid enters the pleural cavity, the negative pressure in the pleural cavity decreases or disappears, or even becomes positive, that is, pneumothorax, fluid chest, liquid pneumothorax, and the lung may be compressed and cannot be opened. In this case, pleural puncture, gas and fluid extraction, or even continuous drainage of the chest cavity is needed to discharge the gas and fluid in the chest cavity and promote the reopening of the lung. If the pleura is affected by diseases such as inflammation or tumors, the two layers of the pleura may become adherent, causing pain and other symptoms.