Foramen of Winslow Hernia

The epiploic foramen of Winslow is a 3-cm potential opening anterior to the inferior vena cava and posterior to the hepatoduodenal ligament (portal vein, common bile duct, and hepatic artery). It is the route of communication between the lesser sac and the greater peritoneal cavity. Bowel may herniate through the foramen of Winslow.

About 10% of internal hernias are through the foramen of Winslow, with the small bowel most commonly involved. Patients with an enlarged foramen of Winslow or redundant or mobile intestinal loops are predisposed to foramen of Winslow hernias.

Radiographs reveal small bowel obstruction associated with gas-containing intestinal loops high in the abdomen (black arrow) and posteromedial to the stomach. Upper gastrointestinal studies will show dilatation of bowel loops with obstruction at the right upper abdomen.

CT will show mesentery (green arrow, mesenteric vessels) between the inferior vena cava (blue arrow) and main portal vein (purple arrow), bowel loops in the lesser sac (yellow arrow) with a beak directed toward the foramen of Winslow, and two or more bowel loops in the high subhepatic space.

Less commonly, there may be herniation of the terminal ileum, cecum, and ascending colon. Hernias involving the transverse colon, omentum, and gallbladder are rare. Imaging findings for these entities may be found in the excellent RadioGraphics article cited below.

References

Takeyama N, Gokan T, Ohgiya Y, Satoh S, Hashizume T, Hataya K, Kushiro H, Nakanishi M, Kusano M, Munechika H. CT of internal hernias. Radiographics. 2005 Jul-Aug;25(4):997-1015.