What is the correct angle for inserting an intramuscular injection?

Inserting an intramuscular injection at a 90-degree angle is correct because this angle allows the needle to penetrate deeply into the muscle tissue, ensuring that the medication is delivered into the muscle rather than subcutaneously (under the skin). Intramuscular injections are meant to be administered directly into the muscle, which has a rich blood supply, allowing for rapid absorption of the medication into the bloodstream.

Using a higher angle, such as 90 degrees, minimizes the risk of injecting the medication into fatty tissue, which could delay the medication's efficacy. Additionally, this angle aligns with the recommended practices for various intramuscular injection sites, such as the deltoid, vastus lateralis, or ventrogluteal muscles, where it is critical to get the medication into the muscle for optimal therapeutic effect.