pleura

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pleura

anatomy

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Plural:: pleurae, or pleuras

Related Topics:: pleural recess; parietal pleura; pleural sac; visceral pleura; mediastinal pleura

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pleura, membrane lining the thoracic cavity (parietal pleura) and covering the lungs (visceral pleura). The parietal pleura folds back on itself at the root of the lung to become the visceral pleura. In health the two pleurae are in contact. When the lung collapses, however, or when air or liquid collects between the two membranes, the pleural cavity or sac becomes apparent (see pleurisy). There are actually two pleural cavities, the right and the left; each constitutes a closed unit not connected to the other. The glistening surface of the pleura is made up of a sheet of flat cells, the mesothelium, which covers an underlying layer of loose elastic tissue. The pleura exudes a thin fluid that keeps it moist and lubricated.

Major disorders of the pleura include pleurisy, the inflammation of the pleura; pleural effusion, the accumulation of excess fluid between the visceral and parietal pleurae; empyema, the collection of pus in the pleural space; mesothelioma and other tumours of the pleura; chylothorax, the rupture of the thoratic duct; hemothorax, the accumulation of blood in the pleural space; and fibrothorax, the encasement of the lung in fibrin following a severe pleural inflammatory process such as empyema.

This article was most recently revised and updated by Kara Rogers.

pleural effusion

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pleural effusion

pathology

Written by John Hansen-Flaschen

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Also called:: hydrothorax

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pleural effusion, accumulation of watery fluid in the pleural cavity, between the membrane lining the thoracic cage and the membrane covering the lung. There are many causes of pleural effusion, including pneumonia, tuberculosis, and the spread of a malignant tumour from a distant site to the pleural surface. Pleural effusion often develops as a result of chronic heart failure because the heart cannot pump fluid away from the lungs, and fluid that seeps from the lungs places additional stress on the dysfunctioning heart. Large pleural effusions can cause disabling shortness of breath.

If symptoms of pleural effusion develop, a tube is inserted through the chest wall into the pleural space to drain the fluid. Under certain conditions, such as malignant disease of the pleura (i.e., mesothelioma), pleural effusion can be treated by introducing an irritating substance called a sclerosing agent into the pleural space in order to stimulate an inflammatory reaction of the pleural surfaces. As the inflammation heals, tissue adhesions obliterate the pleural space, thereby preventing the accumulation of more fluid. Examples of sclerosing agents that cause an inflammatory reaction of the pleural surfaces include talc, doxycycline, and bleomycin.

John Hansen-Flaschen