Intramuscular injection is a common clinical method of drug administration that involves injecting a drug into muscle tissue through a syringe. The most common sites for intramuscular injections are the gluteus maximus and deltoid muscles. The location of gluteus maximus injection is: draw a horizontal line from the apex of the gluteal cleft to the left or right, and make a vertical bisector from the highest point of the iliac crest downward to divide the buttocks into four quadrants, of which the upper outer quadrant is the site of gluteus maximus injection, where injection can avoid sciatic nerve damage. Upper arm deltoid muscle injection method is selected in the lateral upper arm, 2-3 transverse fingers below the shoulder crest, where the muscle is thinner than the muscle pack of the buttocks, and can only be injected in small doses.