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Overview of Pleural and Mediastinal Disorders

By

Richard W. Light

, MD, Vanderbilt University Medical Center

Last full review/revision Jan 2021| Content last modified Sep 2022
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The pleura is a thin, transparent, two-layered membrane that covers the lungs and also lines the inside of the chest wall. The layer that covers the lungs lies in close contact with the layer that lines the chest wall. Between the two thin flexible layers is a small amount of fluid (pleural fluid) that lubricates them as they slide smoothly over one another with each breath. The area containing the fluid is called the pleural space.

Two Views of the Pleura

Two Views of the Pleura

The mediastinum (chest cavity) refers to an area that is bordered by the breastbone (sternum) in front, the spinal column in back, the neck on top, and the diaphragm below. It contains the heart, the thymus gland, some lymph nodes, and parts of the windpipe (trachea), esophagus, aorta, thyroid gland, and parathyroid glands. It does not include the lungs. The mediastinum is divided into three parts:

  • Front (anterior)

  • Middle

  • Back (posterior)

Locating the Mediastinum

Locating the Mediastinum
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