Which sites are used for intramuscular injections in rodents?

• A. Quadriceps and Gluteal muscles
• B. Deltoid and Hamstrings
• C. Triceps and Biceps
• D. Abdominal wall

Answer: (A)

Intramuscular injections in rodents are given into muscle tissue that is large enough to accommodate the injection and easy to access safely. The thigh muscles (quadriceps femoris) and the hip region (gluteal muscles) fit this requirement well in small animals, providing reliable absorption and manageable anatomy for needle placement. The forelimb muscles like those in the shoulder or arm (deltoid, triceps, biceps) are typically too small or awkward to hit reliably in a rodent, increasing the risk of injury or inconsistent delivery. The abdominal wall is not used for IM injections because it’s not a muscle site suitable for intramuscular delivery and is instead used for intraperitoneal injections or other routes. So, the quadriceps and gluteal muscles are the best intramuscular sites in rodents.