Which site is least commonly used for intramuscular injections?

The forearm is the least commonly used site for intramuscular injections primarily because it does not have a large muscle mass that can adequately absorb medications. Intramuscular injections are typically administered into larger muscle groups that can accommodate the volume of medication and provide a reliable absorption rate. The deltoid, gluteus, and vastus lateralis are all more appropriate sites for intramuscular injections, as they consist of deeper and larger muscles.

The deltoid, located in the shoulder, is commonly used for vaccines and other medications in smaller doses. The gluteus is preferred for larger volumes because it can hold more fluid and allows for a slower absorption rate. The vastus lateralis, situated in the thigh, is also a good site, particularly for infants and children. In contrast, the forearm is typically reserved for subcutaneous injections or intravenous access, making it less suitable for intramuscular administration.