Small Intestine
Mesenteric Hernia
Basic Information 
Clinical Presentation
History, Chief Complaint
• Colic. Clinical signs are consistent with small intestinal strangulating lesion (see “Small Intestine: Epiploic Foramen Entrapment” and “Small Intestine: Inguinal Hernia” in this section).
• History of late-term pregnancy or recent parturition is very important in these cases.
Etiology and Pathophysiology
• Mesenteric defects may be congenital in origin or acquired from trauma or previous surgery.
• Late-term pregnancy or traumatic parturition may cause tearing of the mesocolon and potential incarceration of the small intestine.
• Trauma to the mesocolon may also cause avulsion of the blood supply to the small colon, resulting in ischemic necrosis of the small colon.
• The gastrosplenic ligament is the mesenteric attachment between the left part of the greater curvature of the stomach and the hilus of the spleen. Trauma is the suspected cause of defects to this ligament.
• Jejunal mesentery is most commonly involved in small intestinal mesenteric defects. Defects can also be found in the mesentery of the duodenum and ileum.
• Mesenteric defects in the broad ligament are less common.
• Failure of the vitelline artery or duct and its associated mesentery to atrophy during embryonic development forms a mesodiverticular band. These remnants extend from the mesentery to the antimesenteric surface of the distal jejunum. Small intestine may herniate through defects in these structures.
• Although less common, defects may also be found in the mesentery of the large colon and cecum.
