The three layers are: external intercostal muscles, internal intercostal muscles, and the innermost intercostal muscles. These muscles are innervated and supplied with blood by the intercostal nerves, intercostal veins, and intercostal arteries.hey raise the ribs and expand the chest cavity, and originate from ribs one through 11, with insertion from ribs two to 12. The internal intercostal muscles are responsible for forced exhalation. They depress the ribs and decrease space in the chest cavity.
synergism (sinÂ´urjizÉm), n a joint action of two drugs in such a manner that one supplements or enhances the action of the other to produce an effect greater than that which may be obtained with either one of the drugs in equivalent quantity or produce effects that could not be obtained with any safe quantity of either drug, or both.
â¢ SYNERGISTIC (adjective). The adjective SYNERGISTIC has 3 senses: 1. used especially of drugs or muscles that work together so the total effect is greater than the sum of the two (or more). 2. of or relating to the theological doctrine of synergism. 3. working together; used especially of groups, as subsidiaries of a corporation, cooperating for an enhanced effect. Familiarity information: SYNERGISTIC used as an adjective is uncommon.