A nurse is preparing to administer an intramuscular injection to a client. Which of the following injection sites should the nurse choose to utilize?

The vastus lateralis (anterolateral thigh) is a preferred intramuscular injection site, especially for infants and toddlers, as it has a large muscle mass with no major nerves or blood vessels nearby. It is also used in adults when other sites are inaccessible. The abdomen is used for subcutaneous injections (e.g., insulin, heparin). The forearm is used for intradermal injections (e.g., TB test). The upper back is not a standard IM injection site.