Hypodermic injection of drugs or fluids into a muscle.
An injection of liquid into a muscle, e.g. for a slow release of a drug.
Injection into intramuscular tissue, usually the anterior thigh, deltoid, or buttocks. Intramuscular injections are used primarily in the administration of vaccines, immune globulins, long-acting corticosteroids, some antibiotics, some hormones, analgesics, and sedatives. In shock, medications given intramuscularly may not be rapidly absorbed. No more than 4 ml should be injected at one time into an adult with normal musculature; in children and adults with underdeveloped musculature, no more than 2 ml should be injected at one time. Patients should be advised that intramuscular injections, e.g., for vaccination, are painful.