How do you give an injection to a rat's leg? - briefly
Locate the distal thigh muscle of the rat, disinfect the area, and insert a 27–30‑gauge needle at a 45° angle into the muscle, delivering the prescribed volume slowly. Secure the animal gently to prevent movement and observe for any adverse reaction after the injection.
How do you give an injection to a rat's leg? - in detail
Administering a subcutaneous or intramuscular injection into a laboratory rat’s hind limb requires precise preparation, proper restraint, and careful technique to minimize tissue damage and ensure accurate dosing.
First, gather equipment: sterile 1‑ml syringe, appropriate gauge needle (27‑30 G for subcutaneous, 25‑27 G for intramuscular), disinfectant wipes, cotton swabs, a clean work surface, and sharps disposal container. Prepare the injection solution under aseptic conditions, verify concentration, and label the syringe with dose and drug name.
Second, identify the injection site. For subcutaneous delivery, locate the loose skin over the dorsal surface of the hind leg, typically midway between the hip and the knee. For intramuscular administration, target the quadriceps femoris muscle on the anterior thigh, avoiding major nerves and blood vessels. Mark the site with a sterile swab if needed.
Third, restrain the animal. Use a gentle tail‑hold or a transparent restrainer that allows visual monitoring of breathing. Apply minimal pressure to prevent stress while keeping the limb exposed and immobile.
Fourth, clean the skin. Wipe the chosen area with an alcohol pad or povidone‑iodine swab, moving outward from the center to reduce contamination. Allow the surface to dry briefly.
Fifth, insert the needle. Hold the syringe at a 45‑degree angle for subcutaneous injection; insert the bevel upward, advancing the needle just beneath the skin. For intramuscular delivery, use a 90‑degree angle, penetrating the muscle to the full length of the needle. Ensure the needle does not encounter resistance that could indicate bone contact.
Sixth, deliver the dose. Depress the plunger smoothly to inject the calculated volume. Observe for any leakage or backflow; if present, reposition the needle and repeat the injection.
Seventh, withdraw the needle. Pull the needle straight out, apply gentle pressure with a sterile cotton swab to the site, and hold for a few seconds to prevent bleeding. Do not massage the area, as this may alter drug distribution.
Eighth, monitor the rat. Place the animal back in its cage, observe for normal respiration, mobility, and signs of distress for at least 15 minutes. Record the injection details in the laboratory log, including site, volume, needle size, and any adverse observations.
Finally, dispose of all sharps in a puncture‑proof container, decontaminate reusable equipment, and clean the work area according to institutional biosafety protocols.