injection /injek″shən/ [L, in, within, jacere, to throw] , 1. the act of forcing a liquid into the body by means of a needle and syringe. Injections are designated according to the anatomical site involved; the most common are intraarterial, intradermal, intramuscular, intravenous, and subcutaneous. Parenteral injections are usually given for therapeutic reasons, although they may be used diagnostically. Sterile technique is maintained. Compare infusion, instillation, insufflate. 2. the substance injected. 3. redness and swelling observed in the physical examination of a part of the body, caused by dilation of the blood vessels secondary to an inflammatory or infectious process. −inject, v.
