The sound is actually called a Pleural rub.
The purpose of a pleural rub is to hear things on the inside of one's body. For example a machine that can hear the sounds inside a person's lungs when they are breathing to see if things sound normal or if there is a noisy rattling in the lungs, which would cause concern for one's health.
Pleural effusion is excess fluid that accumulates between the two pleural layers, the fluid-filled space that surrounds the lungs. Excessive amounts of such fluid can impair breathing by limiting the expansion of the lungs during ventilation.
It prevents a pleural friction rub. Its like a lubricant for the lungs to move up and down without any friction.
The pleural effusion is any abnormal amount of fluid all around the lungs. It can result to varying types of medical conditions.
Pleural-based opacity refers to opacity seen in X-rays along the pleural surface. The opacity or silhouettes can mean many things like signs of injuries, possible thickening, or indications of disease.
what is pleural thickening
"To rub one out", it means to masturbate.
bronchopleural
Pleural fluid is the fluid that's located between the pleural membranes that cover the lungs. If too much fluid builds up, it's called a pleural effusion.
pleural membrane
Asymmetrical = not the same on each side - i.e. one side is worse than the other. Apical = the top of the lungs. Pleural = The lining of the lung.