What is the typical maximum volume for intramuscular injections in mice?

• A. 0.05 mL
• B. 0.5 mL
• C. 1 mL
• D. 2 mL

Answer: (A)

The amount that can be safely injected into a mouse muscle is very small because the muscle is tiny and delicate. For intramuscular injections in mice, the usual upper limit per site is about 0.05 mL (50 μL). Exceeding this can overstretch muscle fibers, cause local tissue damage or necrosis, and lead to irritation that confounds results. If a higher dose is needed, researchers typically split it across multiple sites or consider a different route (such as subcutaneous or intraperitoneal), depending on the study and welfare guidelines. The larger volumes listed would exceed what a mouse muscle can safely accommodate and would cause significant tissue injury and unreliable outcomes.