Administration of fluid by any root other than the alimentary canal (per oral) i.e. intravenous, intramuscular, subcutaneous or into bone marrow is called Parenteral Fluid Therapy.
Intravenous route is by far the most common method for parenteral fluid therapy. Mostly, the median cubital vein in the cubital fossa is used for venepuncture.
Retainer: The part of Fixed Partial Denture which unites the abutment to the remainder of restoration.
Major retainers are those retainers which cover the entire occluding surface of the tooth. Eg. Full veneer crowns, partial veneer crowns. Minor retainers are small metallic extensions which are cemented on the tooth. Eg. Inlays, Onlays.