Working with the Laboratory Mouse AALAS Practice Test

Understanding mouse abdominal anatomy explains this practice. The cecum, a large pouch in the peritoneal cavity, sits toward the left side in mice. Performing an intraperitoneal injection on the right side keeps the needle path away from this organ, greatly reducing the chance of puncturing the cecum. Avoiding puncture minimizes leakage of intestinal contents, lowers the risk of peritonitis, and reduces variability in how the injected solution distributes. This is why the right-side approach is commonly recommended.