Morison’s pouch, also known as the hepatorenal recess, is a space within the abdominal cavity. This area is a “potential space” situated between two major organs that typically remains collapsed unless filled with fluid. It serves as a natural collection point for fluid inside the abdomen, such as blood or infectious material. The ability of this recess to accumulate fluid makes its location and assessment important in emergency medicine and trauma care.
Precise Anatomical Location
Morison’s pouch is found in the upper right quadrant of the abdomen, positioned high up under the ribcage. It is located deep within the body, situated between the liver and the right kidney. This location is the most gravity-dependent part of the peritoneal cavity when a person is lying flat on their back (supine). This means that any free fluid circulating within the upper abdominal space will naturally flow and pool here first. Fluid from other areas of the abdomen, like the right paracolic gutter, tends to track upward into this recess.
Defining the Space Boundaries
The structure of Morison’s pouch is defined by the organs and membranes that form its walls. Its anterior boundary is formed by the posterior aspect of the right lobe of the liver and the adjacent gallbladder. The posterior wall is formed by the anterior surface of the right kidney and the right adrenal gland situated at the kidney’s superior pole. Superiorly, the space is closed off by the inferior layer of the coronary ligament, which anchors the liver to the diaphragm. The boundaries also extend laterally to the parietal peritoneum lining the right abdominal wall and medially toward the inferior vena cava.
Clinical Relevance in Medical Imaging
The medical significance of Morison’s pouch lies in its role as a sentinel site for fluid accumulation. Because it is the lowest point in the upper abdomen when a patient is supine, it is often the first location where free fluid, such as blood or ascites fluid, becomes visible. Detecting fluid here provides rapid, non-invasive evidence of a potentially serious internal condition.
This feature makes the pouch a cornerstone of the Focused Assessment with Sonography for Trauma (FAST) exam. During this quick ultrasound scan, the right upper quadrant view targets Morison’s pouch to immediately check for signs of hemoperitoneum. The presence of fluid in this recess can indicate significant internal bleeding, which may prompt immediate surgery for an unstable trauma patient.
The pouch is also a common site for the collection of pus, leading to a subphrenic abscess, or the accumulation of fluid from liver disease like cirrhosis. Its visibility on ultrasound allows clinicians to monitor the progression of these conditions or guide procedures to drain the fluid. Assessing this single location enhances the speed of diagnosis and the management of critical patients.