What type of injection is a subcutaneous injection?

A subcutaneous injection involves administering medication under the skin, typically into the fatty tissue layer beneath the dermis. This method allows for the gradual absorption of the medication into the bloodstream, which is particularly useful for certain vaccines and medications that are absorbed slowly. It's an effective way to deliver substances like antibiotics, vaccines, or other fluids when an intravenous route is not feasible or necessary.

The other options do not accurately describe what a subcutaneous injection entails. For instance, injecting into the bloodstream refers to intravenous methods, while vaccinations delivered in the muscle point towards intramuscular injections, which involve a different layer of tissue. Oral delivery indicates medication taken by mouth, bypassing the injection process entirely. Therefore, selecting the choice indicating medication given under the skin aligns perfectly with the definition and process of a subcutaneous injection.