NHA Certified Clinical Medical Assistant (CCMA)Clinical Patient CareMedium
A medical assistant is preparing to administer an intramuscular (IM) injection to an adult patient. Which of the following sites is appropriate for administering a volume of 2 mL?
- AVentrogluteal muscle
- BDorsogluteal muscle
- CDeltoid muscle
- DVastus lateralis muscle
Show answer & explanationAnswer & explanation
Correct answer: A. Ventrogluteal muscle
The ventrogluteal muscle is a safe and common site for IM injections, capable of receiving volumes up to 3 mL in adults. The deltoid is limited to 1 mL, and while the vastus lateralis can take up to 3 mL, the ventrogluteal is often preferred for larger volumes due to less pain and fewer major nerves/vessels.
Why the other options are wrong
- B. The dorsogluteal site is no longer recommended due to the high risk of sciatic nerve injury.
- C. The deltoid muscle is generally limited to a maximum injection volume of 1 mL for adults.
- D. The vastus lateralis muscle can accommodate up to 3 mL but is often used for infants and children; for adults, ventrogluteal is often preferred for larger volumes.
Intramuscular (IM) Injection Sites
Specific anatomical locations chosen for IM injections based on muscle mass, proximity to nerves/vessels, and injection volume.
- Deltoid: Max 1 mL (adults), common vaccines.
- Vastus Lateralis: Up to 3 mL (adults), common in infants/children.
- Ventrogluteal: Up to 3 mL (adults), preferred for larger volumes, safest site.
- Dorsogluteal: Not recommended due to sciatic nerve risk.
Memory trick: Vast Ventro's Volume, Deltoid's Dainty Dose