Key Points

■ The pleura is made of two serosal membranes, one covering the lung (visceral pleura) and one covering the inner chest wall and mediastinum (parietal pleura).

■ The visceral pleura is devoid of somatic innervation, whereas the parietal pleura is innervated through a rich network of somatic, sympathetic, and parasympathetic fibers.

■ Pleural fluid is constantly secreted, mostly by filtration from the microvessels in the parietal pleura.

■ The resorption of pleural fluid may be through lymphatic stomata in the parietal pleura rather than through the visceral pleura.

■ The pleural pressure, which is subatmospheric, is proportional to the pressure developed within the lung.