ABSTRACT
In normal conditions, the pleural space contains a small amount of pleural uid.1 is small volume of pleural uid is maintained in the pleural space by a complex interplay of hydrostatic pressures and lymphatic drainage, which allows for steady liquid and protein turnover.1,2 Pathological processes may lead to the development of pleural eusions by causing disequilibrium between the rates of pleural uid formation and pleural uid absorption (see Chapter 5). e focus of this chapter is on the normal pleural uid volume and its cellular and solute content in normal, physiological circumstances.
