Free AAMA Certified Medical Assistant (CMA) Practice Question

The correct answer, a needle gauge of 22–25 and a length of 1–1.5 inches, is appropriate for intramuscular injections in adults. This size allows for adequate penetration into the muscle tissue without causing unnecessary damage. A 28–31 gauge needle is typically used for subcutaneous injections, as it is finer and shorter, not reaching the muscle layer effectively. The 18-gauge needle, while the appropriate gauge for intramuscular injections, at a length of 2 inches would be too long for most intramuscular injections, increasing the risk of hitting bone or penetrating too deeply. A needle length of ½ inch is too short to penetrate the muscle tissue adequately for an intramuscular injection.