Morrison’s Pouch, also known as the hepatorenal recess, is a potential space within the abdominal cavity. This space is not a true anatomical pouch, but rather a potential gap that becomes apparent when fluid accumulates. It is named after British surgeon James R. Morrison. In a healthy individual, this space is typically empty, with the liver and kidney in direct contact or separated by minimal tissue.
Its Anatomical Location
Morrison’s Pouch is situated in the upper right part of the abdomen, specifically between the right lobe of the liver and the right kidney. This location places it within the peritoneal cavity, the space between the two layers of the peritoneum, a membrane lining the abdominal wall and organs.
The boundaries of Morrison’s Pouch are defined by several surrounding structures. Anteriorly, it is bordered by the inferior surface of the right liver lobe and the gallbladder. Posteriorly, it is adjacent to the superior part of the right kidney, the right adrenal gland, and parts of the duodenum and hepatic flexure of the colon.
The superior boundary is formed by the inferior layer of the coronary ligament. Laterally, the space is limited by the parietal peritoneum lining the right abdominal wall. This arrangement makes it the most gravity-dependent space in the upper abdomen when a person is lying on their back.
Why It Matters Clinically
Morrison’s Pouch is a primary collection point for free fluid within the abdominal cavity. As the most dependent part of the peritoneal cavity in a supine position, gravity causes fluids like blood, pus, or ascitic fluid to accumulate here. Even small amounts, as little as 30 to 40 mL, can be detected.
Fluid in Morrison’s Pouch signals various underlying medical conditions. For instance, in trauma cases, internal bleeding (hemoperitoneum) from injured organs like the liver can collect here, indicating serious injury. This makes it an important area for assessing patients after blunt abdominal trauma. Fluid accumulation can also result from ascites, an abnormal fluid buildup caused by conditions like liver cirrhosis or heart failure.
Beyond trauma and ascites, Morrison’s Pouch can collect inflammatory fluids or pus from infections spreading within the abdomen, such as acute cholecystitis or peritonitis. The space can also be involved in the spread of certain cancers, as peritoneal fluid dynamics can carry metastatic deposits to this dependent location. Detecting fluid here is a significant diagnostic indicator, guiding medical professionals toward identifying and managing potentially life-threatening conditions.
How It Is Examined
Medical professionals examine Morrison’s Pouch using imaging techniques to detect abnormal fluid collections. Ultrasound is a commonly used, non-invasive, and cost-effective method for this assessment. During an ultrasound, the area between the liver and the right kidney is visualized to identify anechoic (black) regions, which indicate fluid.
In trauma settings, the Focused Assessment with Sonography for Trauma (FAST) exam routinely includes a view of Morrison’s Pouch to rapidly detect free fluid, suggesting internal bleeding. This quick bedside examination allows for prompt decision-making regarding patient management. Computed Tomography (CT) scans also provide detailed images of Morrison’s Pouch, allowing for a comprehensive evaluation of fluid collections, their characteristics, and potential underlying pathologies. These imaging modalities are important in diagnosing conditions indicated by fluid in this space.