3-Year-Old MN Mixed Breed Dog

Signalment & History

A 3 year old MN mixed breed dog presented for a 2 day history of vomiting.

Left lateral abdomen Right lateral abdomen Caudal Right lateral abdomen VD abdomen


There are 2 population of small intestinal segments with a normal population measuring less than 1.5 times the mid body height of L5 and multiple gas dilated segments measuring up to 2.3 times the mid body height of L5. Within the stomach there is a moderate amount of gas. Diffusely throughout the abdomen, there is a decrease in abdominal serosal detail with ill-defined soft tissue opacities.


Small intestinal mechanical obstruction with moderate volume peritoneal effusion.


In dogs, the general rule to determine if a small intestine segment is abnormally enlarged was developed, comparing the maximal diameter of the small bowel loop (serosa to serosa) with the narrowest height of the body of L5. A normal small intestinal segment has small intestine diameter-to-narrowest height of the body of L5 ratio of up to 1.6. Sometimes it is difficult to differentiate the questionable enlarged small intestinal segment from a normal part of the colon. In order to try to solve this problem, pneumocolon or barium enema can be performed.


Graham JP, Lord PF, Harrison JM. Quantitative estimation of intestinal dilation as a predictor of obstruction in the dog. J Small Anim Pract. 1998 Nov;39(11):521-4.