Intradermal injections are usually administered to the inner forearm or shoulder blade on the upper back, according to the Medical Education Division of the Brookside Associates. Intramuscular injections are given in the buttocks, upper arm area or thigh.
Brookside Associates states there are three types of injections: intradermal, intramuscular and subcutaneous. An intradermal injection provides a tiny amount of fluid into the skin's dermal layer. It is given in soft and yielding parts of the body, usually the inner forearm. An intramuscular injection is used to administer long-lasting and rapid-acting medication, and is considered the easiest, safest and best-tolerated type of injection. It is injected into the deep muscle tissue, where it forms a deposit of medication that is slowly absorbed into the bloodstream. The medication dosage determines the site of injection. The preferred site for intramuscular injection is often the buttocks, as the muscles of the gluteal region are thick and frequently used, making it easy for the body to absorb drugs. Intramuscular injections are also given on the outer thigh. Subcutaneous injections are commonly used for medications that require a slower absorption rate than intramuscular injections. Injection sites include the outer region of the upper arm, outer area of the upper leg and buttocks.