From the Guidelines
The recommended site for intramuscular injections in infants is the anterolateral thigh, as specified in the most recent guidelines 1. To administer:
- Position the infant on their back or side
- Locate the muscle by dividing the thigh into thirds and identifying the middle portion on the outer side
- Pinch the muscle gently to separate it from underlying bone
- Insert the needle at a 90-degree angle into the muscle
- Aspirate to ensure you're not in a blood vessel
- Inject the medication slowly Use a 5/8-inch to 1-inch needle, depending on the infant's size, as recommended by previous studies 2, 3, 4. The anterolateral thigh is preferred because it's easily accessible, has a large muscle mass, and is away from major nerves and blood vessels. This site can accommodate up to 1 mL of medication in infants. Always use proper aseptic technique and follow specific medication guidelines for dosage and administration. Rotate injection sites if multiple doses are required to prevent tissue damage and ensure proper absorption. The most recent guidelines 1 emphasize the importance of proper technique and site selection for intramuscular injections in infants.
From the Research
Intramuscular Injection Sites in Infants
- The anterolateral thigh is a common site for intramuscular injections in infants, with studies suggesting that the optimal needle length depends on the technique employed 5.
- Ultrasound measurements have been used to determine the subcutaneous and muscle layer thickness at the anterolateral thigh in infants, with mean subcutaneous tissue thickness ranging from 8.1 to 10.2 mm and muscle layer thickness ranging from 10.5 to 16.5 mm 5.
- Another study found that the mean skin to muscle and skin to bone distance in the anterolateral thigh of infants aged ≤12 weeks was 17.04 mm, with significant variations depending on the infant's weight 6.
Alternative Injection Sites
- The ventrogluteal site has been suggested as an alternative site for intramuscular injections in children under the age of three, with studies showing that the muscle in this site is adequately developed even in infants between 1-12 months old 7, 8.
- Ultrasound measurements have been used to compare the subcutaneous and muscle layer thickness at the anterolateral, deltoid, and ventrogluteal sites in children, with results suggesting that the ventrogluteal site may be suitable for intramuscular injections in children aged 36 months and under 7, 8.
Considerations for Intramuscular Injections in Infants
- The technique of administering intramuscular injections involves attention to the appropriate site of needle insertion, needle size, and angle of injection, with the goal of minimizing complications such as muscle contractures and nerve injury 9.
- The choice of injection site depends on the age and size of the child, with multiple injection sites potentially being preferable in some cases 9.