Where are the sites for intramuscular injections?

I believe almost everyone has had an injection. Nowadays, once a baby is not feeling well, hospitals like to give the child an injection or an IV drip. This phenomenon is very common. Therefore, it is rare to find someone who has never had an injection. However, when it comes to some common knowledge about intramuscular injections, everyone's understanding is still rather one-sided. So, where are the sites for intramuscular injections? Please see the detailed introduction below.

The buttocks, which have thicker muscles and are far away from large nerves and blood vessels, are usually chosen. This is often called "injection in the buttocks" in daily life. In fact, the injection can also be made in the deltoid muscle of the upper arm. The difference between it and skin injection is that the injected drug is more irritating, the amount of medicine is larger, a larger needle and syringe are used (1 ml syringe for skin injection, 2-5 ml syringe for intramuscular injection), the needle is inserted deeper and the syringe is perpendicular to the skin surface.

In clinical practice, intramuscular injections are generally performed in the gluteus maximus, and some injections are performed in the deltoid muscle and biceps brachii. However, as to the specific location for intramuscular injections in the deltoid muscle, it is generally believed that the injection can be performed in the entire muscle. However, in many years of clinical practice, we have found that in some individual cases, improper intramuscular injection sites led to damage to the radial nerve and axillary nerve, while some directly affected the radial nerve and glial nerve trunks.

Method 1: Thumb-fixed point: The patient lies prone or stands, and the surgeon places the middle finger of one hand (the surgeon uses the left hand for injection on the left buttocks and the right hand for injection on the right side) on the patient's anterior superior iliac spine. The thumb is parallel and backward and bent, and the point touched by the fingertip is the injection point (approximately 2 to 3 horizontal fingers above the inner side of the greater trochanter).

Method 2: Three-line determination: (1) Horizontal line: from the anterior superior iliac spine around the dorsal side to the gluteal cleft; (2) Vertical line: draw a vertical line that bisects one buttock and intersects with the horizontal line.

Where are the sites for intramuscular injections? After the detailed introduction above, everyone should now have a clearer understanding of some knowledge about intramuscular injection. In fact, when people get injections, they usually inject the gluteus maximus muscle, which is relatively safe. Other injection sites are just not so common.