Injection (medicine)
An
injection is an infusion method of putting fluid into the body, usually with a syringe and a hollow needle which is pierced through the skin to a sufficient depth for the material to be administered into the body. An injection follows a parenteral route of administration; that is, administration via a route other than through the digestive tract. Since the process inherently involves a small puncture wound to the body, fear of needles is a common phobia. There are several methods of injection or infusion used in humans, including intradermal, subcutaneous, intramuscular, intravenous, intraosseous, intraperitoneal, intrathecal, epidural, intracardiac, intraarticular, intracavernous, and intravitreal. Rodents used for research are often administered intracerebral and intracerebroventricular injections as well. Long-acting forms of subcutaneous/intramuscular injections are available for various drugs, and are called
depot injections. Injections are among the most common health care procedures, with at least 16 billion administered in developing and transitional countries each year.