Morison Pouch

recessus hepatorenalis

Morison pouch (hepatorenal recess) is the peritoneal space between the right lobe of the liver anteriorly and the right kidney and adrenal posteriorly. It is the most dependent part of the peritoneal cavity in the supine position and the first place where free peritoneal fluid accumulates in intraperitoneal haemorrhage, ascites, or hollow viscus perfusion. It is bounded superiorly by the right triangular ligament and inferiorly by the hepatic flexure.

Region: Abdomen

Clinical Relevance

Clinical Notes

Morison pouch is the primary target for the FAST (Focused Assessment with Sonography in Trauma) examination, where the presence of free fluid (anechoic stripe between the liver and kidney) indicates significant intraperitoneal haemorrhage in trauma, guiding the decision for emergency laparotomy. Fluid in Morison pouch in the absence of trauma suggests ascites, haemoperitoneum from ectopic pregnancy rupture, or bowel perfusion. A negative FAST in Morison pouch does not exclude retroperitoneal bleeding.

Pathology

Common Injuries & Conditions

Free Fluid in Morison Pouch on FAST Examination

Detection of anechoic fluid in Morison pouch by bedside ultrasound in trauma is the most reliable FAST finding for intraperitoneal haemorrhage, with as little as 250 mL of free fluid detectable; a positive FAST with haemodynamic instability mandates immediate laparotomy without CT confirmation.