1) Contractile organ 2) Contractor 3) Within a muscle 
(intra- + L. musculus muscle) within the substance of a muscle.
(IM) An injection into the muscle.
Within or into muscle. Also called IM.
Into the muscle: This term is usually used with reference to injections that are given into the cat's muscle.
<anatomy> Within the substance of a muscle. ... Origin: L. Musculus = muscle ... (18 Nov 1997) ... 
(in″trә-mus´ku-lәr) within the muscular substance.
Given into muscles - where the needle goes into the muscle layer under the skin in order to deliver medicine, usually the hind leg. This route is generally given when quick action is required.
Occurring within the substance of a muscle.
(IM) In the muscle
(IM) Type: Term Pronunciation: in′tră-mŭs′kyū-lăr Definitions: 1. Within the substance of a muscle.
Into the muscle: frequently in reference to injections.
[adj] - within a muscle
adjective within a muscle; `an intramuscular injection`
Injections given in the muscle.
located or occurring within a muscle.