Fundamentals Of Nursing – Communication Practice Test

Understanding where and how much can be injected into muscle is about matching the dose to the size and safety of the muscle. The deltoid muscle in the upper arm is relatively small, so it has a limited capacity to hold intramuscular injections. For most adults, the deltoid is best for small volumes—about 1 mL. A 3 mL dose would overfill this site, increasing pain, tissue irritation, and the chance that the medication ends up deposited in subcutaneous tissue rather than truly in muscle, with unreliable absorption. Other sites with thicker, well-developed muscle—like the ventrogluteal area and the vastus lateralis—can safely accommodate a 3 mL dose and provide better absorption. The dorsogluteal site, while able to hold larger volumes, is avoided in many practices because of the risk to the sciatic nerve and less reliable landmarks. Thus, the deltoid is the least appropriate choice for a 3 mL IM dose.