Intramuscular injections mainly avoid blood vessels and nerves, as well as important tissues and organs. The common places for intramuscular injection are mainly the deltoid and gluteal muscles, the reason is very simple, because there are fewer important tissues, structures and organs here, and the muscles and subcutaneous tissues are thicker, which will not hurt the important tissues when injecting drugs. After the needle is inserted into the body, it needs to be pumped back to prevent it from being inserted into blood vessels. Before injection, it needs to be carefully sterilized and the injection position needs to be changed, so repeated injections in the same position will cause great pain to the patient, and it is also easy to cause the formation of hard lumps in the local muscles. The advantage of intramuscular injection is that it is absorbed faster, and it can also avoid the stimulation of blood vessels by drugs, but it must be careful not to damage important structures.