Liver Anatomy, Function, and Ultrasound Principles for Medical Students Practice Test

Fluid and pus tend to pool in the subphrenic spaces because they lie just beneath the diaphragmatic dome and communicate with the rest of the peritoneal cavity. This creates large dependent pockets (right and left subphrenic spaces) that are common sites for abscess formation after upper abdominal infections, perforations, or surgery. An abscess here often presents as a complex fluid collection under the diaphragm on imaging, and patients may have fever and upper abdominal or shoulder pain. While the hepatorenal (Morrison’s) pouch is another dependent area where free intraperitoneal fluid can collect in a supine patient, abscesses are classically described in the subphrenic spaces. The pericardial space is not a peritoneal space, so it’s not the site for intraperitoneal abscess.