Transdiaphragmatic movement of abdominal fluid into the pleural space, seen with ascites or pancreatic pseudocyst rupture, is an example of which mechanism?

• A. Transdiaphragmatic movement
• B. Increased hydrostatic pressure
• C. Decreased intrapleural pressure
• D. Rupture of vessels

Answer: (A)

The main idea is that fluid can move directly from the abdominal cavity into the chest through small openings in the diaphragm. When there is ascites or a ruptured pancreatic pseudocyst, the pressure inside the abdomen rises and pushes fluid upward through diaphragmatic fenestrations or defects into the pleural space, creating a pleural effusion. This transdiaphragmatic passage relies on a diaphragmatic conduit and a favorable pressure gradient, rather than changes in the pleural space itself or rupture of blood vessels.