Where should a subcutaneous injection be administered?

A subcutaneous injection is typically administered into the fatty tissue just under the skin, which is found overlying areas such as the triceps, abdomen, or thigh. This type of injection is designed to allow for a slow and steady absorption of the medication into the bloodstream.

The fatty tissue in the triceps area serves as an appropriate site for subcutaneous injections due to its accessibility and the presence of adequate subcutaneous tissue. This area is generally safe and effective for the administration of various vaccines and medications that are intended to be absorbed slowly.

The other options represent incorrect sites for subcutaneous injections. The deltoid muscle is suitable for intramuscular injections, while the thigh muscle is also used for intramuscular administration. Directly injecting into the abdomen can be appropriate for certain substances but may not represent the most common site for subcutaneous injections. Thus, option B is the correct choice for where a subcutaneous injection should be administered.