Certified Medical Assistant (CMA AAMA)PharmacologyMedium
A medical assistant is preparing to administer an intramuscular injection into the deltoid muscle of an adult patient. Which of the following needle gauges is most appropriate for this procedure?
- A18 gauge
- B25 gauge
- C21 gauge
- D27 gauge
Show answer & explanationAnswer & explanation
Correct answer: C. 21 gauge
For intramuscular injections, a 21-23 gauge needle is typically recommended for adult patients, especially in the deltoid muscle. This gauge is sufficient to penetrate the muscle tissue and deliver the medication effectively.
Why the other options are wrong
- A. 18 gauge is too large and generally used for thicker solutions, blood transfusions, or emergency situations.
- B. 25 gauge is generally used for subcutaneous injections due to its smaller diameter.
- D. 27 gauge is very small and typically used for intradermal injections or very sensitive areas.
Intramuscular Needle Gauge
The appropriate needle gauge for intramuscular injections in adults is typically 21-23 gauge.
- Deltoid muscle is a common IM injection site.
- Gauge selection depends on medication viscosity, patient size, and injection site.
- Larger gauge numbers indicate a smaller needle diameter.
Memory trick: IM needles are 'Just Right' at 21-23.