What is the definition or description of: intramuscular injection?

Shot into muscle!: Intramuscular (im) injection is a shot given in large muscle groups, typically shoulder (deltoid), thigh (vastus lateralis) and/or butt (gluteus). Check out http://en.Wikipedia.Org/wiki/intramuscular_injection & http://www.Drugs.Com/cg/how-to-give-an-intramuscular-injection.Html for more info.

Deep into the muscle: Any shot given into the muscle as against under the skin and or into the vein.