Certified Medical Assistant (CMA AAMA)PharmacologyEasy
A medical assistant is preparing to administer an intramuscular immunization to a 2-month-old infant. Which site is recommended for this injection?
- AVastus lateralis muscle
- BVentrogluteal muscle
- CDorsogluteal muscle
- DDeltoid muscle
Show answer & explanationAnswer & explanation
Correct answer: A. Vastus lateralis muscle
The vastus lateralis muscle, located on the anterolateral thigh, is well-developed even in infants and is the preferred IM injection site for infants under 12 months of age. The deltoid is too small in infants, and the dorsogluteal site risks sciatic nerve injury.
Why the other options are wrong
- B. The ventrogluteal site is acceptable for infants over 7 months but the vastus lateralis remains the standard choice for younger infants.
- C. The dorsogluteal site is avoided in infants due to underdeveloped muscle and proximity to the sciatic nerve.
- D. The deltoid is not fully developed in infants and is used later in toddlers/older children.
Vastus Lateralis Injection Site
The anterolateral thigh muscle used as the preferred IM injection site for infants and young children.
- Located between greater trochanter and knee
- Preferred for infants under 12 months
- Avoids sciatic nerve injury risk
Memory trick: 'Babies get it in the thigh, not the hip'