Pleurapussi

Pleurapussi, or the pleural sac, is the double-layered serous membrane that surrounds the lungs and lines the inner surface of the chest wall. It comprises the visceral pleura, which covers the lungs, and the parietal pleura, which lines the chest wall, the diaphragm, and the mediastinum. The two layers enclose the pleural cavity, a potential space that normally contains a small amount of pleural fluid. This fluid lubricates the surfaces and, together with the membranes’ cohesion, creates surface tension that helps keep the lungs inflated as the chest wall moves during breathing.

Function and structure: The pleural membranes facilitate smooth lung movement and reduce friction during respiration. The pleural fluid allows gliding of the pleural surfaces, aids in lung expansion, and helps maintain negative intrathoracic pressure needed for inhalation.

Clinical relevance: Diseases affecting the pleura include pleuritis (inflammation of the pleura), pleural effusion (accumulation of fluid in the pleural space), pneumothorax (air in the pleural space), and hemothorax (blood in the pleural space). Symptoms often include chest pain and shortness of breath. Diagnosis relies on imaging such as chest X-ray, ultrasound, or CT scan, sometimes with thoracentesis to remove fluid or air. Treatments vary by condition and may include drainage, stenting of the pleural space, or pleurodesis to prevent recurrent effusions.

Development and supply: The pleural membranes arise from mesodermal tissue; they receive innervation from intercostal and phrenic nerves, and vascular supply from bronchial and surrounding vessels, with lymphatic drainage to mediastinal nodes.