How can you give an injection to a rat's leg? - briefly
Secure the rat in a restraining device, locate the lateral thigh muscle, disinfect the area, and insert a sterile needle at a 45° angle into the muscle to deliver the required volume. Withdraw the needle smoothly and observe the animal for any adverse reactions.
How can you give an injection to a rat's leg? - in detail
Administering an injection into a rat’s hind limb requires strict aseptic technique, appropriate equipment, and precise anatomical knowledge.
Select a suitable syringe (1 ml or 0.5 ml) and a needle of 25–27 G, ½ in. for intramuscular delivery or 30–31 G, ⅜ in. for subcutaneous administration. Prepare the drug according to the required concentration and volume, and label the syringe clearly.
Restrain the animal using a tail‑held or plexiglass restrainer to minimize stress while allowing access to the thigh. Clean the injection site with 70 % ethanol, allowing the skin to dry before needle insertion.
Identify the target muscle, typically the vastus lateralis on the lateral thigh. For intramuscular injection:
- Insert the needle at a 45° angle to the skin surface.
- Advance the needle until the hub contacts the muscle, usually 3–5 mm depth for adult rats.
- Aspirate gently to confirm absence of blood.
- Depress the plunger slowly to deliver the full dose.
- Withdraw the needle at the same angle and apply gentle pressure with sterile gauze.
For subcutaneous injection:
- Pinch a fold of skin on the lateral thigh.
- Insert the needle bevel up at a 30° angle, 2–3 mm depth.
- Confirm no blood return, then inject the solution.
- Release the skin fold and monitor for any leakage.
After injection, observe the animal for at least five minutes to ensure normal respiration and locomotion. Dispose of the needle in a sharps container and clean the work area with disinfectant.
Document the procedure, including drug name, concentration, volume, needle gauge, injection site, and any observed reactions. This record supports reproducibility and compliance with institutional animal care guidelines.