The pleura and the mediastinum are two parts of the body surrounding or close to the lungs. The pleura is a thin, transparent membrane made up of two layers: one that covers the lungs and one that covers the inside of the wall of the chest. There is a small amount of fluid between these layers, in what is called the pleural space.
The mediastinum is an area that lies between the spinal column and the breastbone, below the neck and above the diaphragm. The mediastinum contains the heart, thymus gland, lymph nodes, esophagus, aorta, thyroid gland, and parathyroid glands, but it does not contain the lungs.
There are several disorders that can affect the pleura and/or mediastinum. These include:
- Pleural effusion: excess fluid that accumulates in the pleural space and can prevent the lungs from expanding normally. Pleural effusions may be caused by heart, liver, and kidney failure or may be related to inflammatory, infectious, and malignant diseases.
- Pneumothorax: air that leaks from the lungs then accumulates in the pleural space leading to partial or complete lung collapse
- Pleurisy: infection or inflammation of the pleural layers
- Mediastinal masses: the formation of abnormal growths, such as cysts or tumors in the mediastinum
- Mediastinitis: an infection or irritation of the mediastinum
- Pneumomediastinum: the accumulation of air in the mediastinum after it leaks out from the lungs