There are many ways of administration, and different choices will be made because of the fast or slow action time of the drug. The slowest action is oral, because it needs to be absorbed through the blood vessels of the stomach to achieve the drug effect, and the fastest is intravenous injection, because it is directly hit on the blood stream, usually a drop. Spanking is a kind of intramuscular injection, which takes a moderate time. It is to inject drugs into muscles, so that small blood vessels in muscles can slowly absorb them and take effect slowly. The common parts of intramuscular injection are the arms and buttocks, and the gluteal muscles are often chosen, because the gluteal muscles are thick and difficult to penetrate deep blood vessels. There are many nerves around the buttocks. In order to avoid hurting the nerve buttocks, the needles are placed on the outer upper part of the unilateral buttocks. 1/4 buttocks. Thick muscle tissue can avoid bone injury and loose muscle tissue, which is beneficial to drug absorption!