The method of giving injections on the buttocks was introduced in the 1970s and 1980s and continues to this day. There are so many parts on the body of the person, why should give an injection dozen buttocks?
A needle in the buttock, known medically as an intramuscular injection, is a drug injected into the muscle and then slowly absorbed into the bloodstream, where it is processed by the liver before it can take effect. Many drugs cannot be injected directly into the blood vessels, which would be life-threatening, so injections should be injected into the muscles, not the blood vessels.
The reason that give an injection chooses coxal, because this one place has the muscle with the richest and thickest in human body, big blood vessel and nerve are less. The buttocks are covered with numerous dense capillaries, which allow drugs to enter the blood vessels slowly, and the needle is not easy to hurt the bone. The muscle on buttocks is more developed, also ensured the absorbability of medicinal effect and the lasting of action, inject on buttocks not only is advantageous to the absorption of medicinal liquid, and still can reduce the loss of medicinal effect.
But the buttock has the fat subcutaneous fat, when inject, must make sure the needle passes through adipose layer, plunge into muscle. Otherwise the liquid is injected into the fat, it has no effect.
When giving an injection to the buttocks, want to avoid to be nervous as far as possible, because buttocks nerve is not sensitive, when giving an injection can let a person feel slight pain only. But too much stress increases the ability of nerves to sense pain, and the muscles in the buttocks contract, preventing the needle from sticking in.