Cecum location in rats and the implications for intraperitoneal injections

Intraperitoneal injection is a common route for parenteral administration of drugs in rodents. A serious consequence associated with this technique, however, is the puncture of vital organs such as the cecum, which causes pain and occasionally peritonitis. Reports have described the cecum as located on either side of the lower abdominal cavity, contributing to the idea that intraperitoneal injections can be performed in either side. The authors investigated the location of the cecum in adult male and female albino and pigmented rat strains, and evaluated the consequences of intraperitoneal injections in the right and left portion of the lower abdomen. Of the rats they investigated, 71.8% had ceca on the left side of the abdomen. The authors also found that injections on the left side were more likely to result in punctured ceca.