Patient Care Technician Certification (PCTC) AMCA Practice Exam

What muscle is commonly used for intramuscular injections?

1. Deltoid

2. Vastus lateralis

3. Gluteus maximus

4. Rectus abdominis

The correct answer is: Vastus lateralis

The vastus lateralis muscle is frequently utilized for intramuscular injections due to its size and accessibility. This muscle, located on the lateral aspect of the thigh, is particularly suitable for infants and young children where other sites may be less appropriate due to smaller muscle mass. Intramuscular injections into the vastus lateralis allow for a significant volume of medication to be delivered while minimizing the risk of injury to nearby nerves and blood vessels. Additionally, this site is recommended for those who might not have fully developed muscle tissue in other areas, making it a safe and effective choice for administering vaccines and medications. While the deltoid muscle is another potential site for intramuscular injections, especially in adults, it has limitations in size and volume capacity. The gluteus maximus, though historically used, carries a higher risk of hitting the sciatic nerve or major blood vessels. The rectus abdominis, on the other hand, is primarily suited for subcutaneous injections, not intramuscular ones. Thus, the vastus lateralis stands out as the most appropriate site in many scenarios involving intramuscular injections.