How can I give an injection to a rat's leg? - briefly
Secure the rat in a restraining device, locate the mid‑thigh region over the quadriceps femoris, and insert a 27‑30 G needle at a 45° angle to deliver the dose intramuscularly; withdraw the needle and monitor the animal.
How can I give an injection to a rat's leg? - in detail
Administering a substance into a rat’s hind limb requires precise preparation, proper restraint, and correct technique to ensure accurate dosing and minimize trauma.
Begin with equipment selection. Use a sterile 1‑ml syringe fitted with a 25‑30‑gauge needle, length ½‑¾ in. Choose a needle long enough to reach the muscle without penetrating bone. Prepare the injectable solution under aseptic conditions; draw the required volume, remove air bubbles, and label the syringe.
Restrain the animal using a clean, padded sheet or a specialized rodent restrainer. Hold the rat in a supine position, exposing the lateral thigh. Locate the quadriceps femoris muscle by palpating the thick muscle mass on the outer side of the hind limb, midway between the hip and knee joints. Avoid the femoral vein and nerve, which lie deeper and medially.
Disinfect the injection site with 70 % ethanol or an appropriate antiseptic, allowing it to dry. Insert the needle at a 45‑degree angle to the skin, bevel up, and advance until the tip penetrates the muscle bulk—typically 2‑3 mm for a 25‑gauge needle. Aspirate gently to confirm the needle is not within a blood vessel; absence of blood indicates correct placement.
Inject the solution steadily over 5‑10 seconds to reduce tissue disruption. Withdraw the needle smoothly, apply gentle pressure with sterile gauze to the site, and observe the rat for at least 5 minutes for signs of distress, bleeding, or adverse reactions.
Dispose of all sharps in a puncture‑proof container and clean the work area with an appropriate disinfectant. Document the injection details, including animal identification, dose, volume, needle size, and any observations.