The inside of a dog's body is not so different from the inside of a human being. The abdominal cavity is lined with a curtain-like tissue called the mesentery, from which the intestines hang. The mesentery is secured by a relatively small support structure, called the mesenteric root. Because the root is relatively small, the mesentery can twist on this support, causing internal damage. The mesentery is also prone to various tumors and to herniation.
The mesentery consists of the root and the blood vessels. The root attaches the mesentery to the abdominal wall. The blood vessels provide nutrients to the intestines. In addition to the blood vessels, the mesentery also contains lymph vessels. Lymph vessels are part of the system that transport nutrients away from the gastrointestinal tract into the body.
Intestinal cancers will frequently find their way to the mesenteric lymph nodes when they spread to other organs. The mesentery omentum, where body fat is stored, is also a site for metastases. Cancers that affect both the large intestine and the small intestine may metastasize to the mesentery. Lymphosarcoma, cancer of the small intestine, is the most common intestinal tumor found in dogs.
Sometimes the mesentery twists on its root, cutting off the blood supply to the intestines and causing intestinal tissue to die. This process, called torsion, can be caused by infections and diseases and conditions that cause bowel irritations, such as parvo, inflammatory bowel disease, foreign body obstructions and others. Torsion also can be caused if the dog plays or exercises too hard after eating. Puppies and adolescent dogs, collies and German shepherd dogs are all prone to mesenteric torsion. Dogs can die from mesenteric torsion unless it is quickly detected and corrected.
A hernia is formed when a portion of a dog's intestines pass through a hole or a tear in the mesentery wall. Sometimes a vet can diagnose a hernia by using X-rays. However, some hernias can be detected only through surgery. Hernias are often treated using surgery, as well. This surgery may include detaching any intestinal tissue that may have become attached to the mesentery. It also may consist of removing any parts of the intestine that have died from being denied blood when it protruded through the mesentery wall. A dog with a mesenteric hernia has a good chance of recovery if the intestine has suffered little damage. A mesenteric hernia also is called a strangulated obstruction.