What is the correct needle insertion angle for an intramuscular injection?

The correct needle insertion angle for an intramuscular injection is 90 degrees. This angle is essential because intramuscular injections are designed to deposit medication deep into the muscle tissue, where it can be absorbed effectively into the bloodstream.

Using a 90-degree angle ensures that the needle penetrates through the skin and subcutaneous tissue directly into the muscle. If the angle were less than 90 degrees, such as with a 45 or 30-degree angle, the medication might not reach the muscle, which could lead to inadequate absorption and reduced efficacy of the medication. Additionally, a 75-degree angle would still result in a more shallow penetration than optimal for intramuscular injections. Thus, the standard practice is to insert the needle at a full 90 degrees for intramuscular administration.