Anatomy and Applied Physiology of the Pleural Space.

The unique anatomy and physiology of the pleural space provides tight regulation of liquid within the space under normal physiologic conditions. When this balance is disrupted and pleural effusions develop, there can be significant impacts on the respiratory system. Drainage of effusions can lead to meaningful improvement in symptoms, primarily owing to improvement in the length-tension relationship of the respiratory muscles. Ultrasound examination to evaluate the movement and function of the diaphragm, as well as pleural manometry, have provided a greater understanding of the impact of pleural effusion and thoracentesis.