For a 9 month old receiving an IM injection, which site is recommended?

The vastus lateralis muscle, located on the anterolateral thigh, is the recommended site for intramuscular (IM) injections in infants like a 9-month-old. This muscle is well-developed in infants and provides a large, safe area for the injection, minimizing the risk of damaging nerves or blood vessels that may be more present in other sites.

The gluteus muscle, although sometimes used in older children and adults, is not recommended for infants due to the relative underdevelopment of the muscle and the proximity to the sciatic nerve, which presents a higher risk for complications. Similarly, the deltoid muscle is not generally recommended for infants until they are older because it may not be well developed enough to provide a sufficient muscle mass for IM injections. Overall, the vastus lateralis is favored because it is both effective and safe for administering vaccines in younger patients.