What are Intramuscular Injection Sites?

Mary McMahon
Mary McMahon

Intramuscular injection sites are sites on the body which have been identified as suitable for intramuscular injections. These types of injections involve the administration of medication into the middle of a muscle. The blood vessels which supply the muscle will distribute the medication throughout the body, allowing it to diffuse from the injection site. A number of medications can be delivered this way in a hospital as well as a home environment, and the injection technique is relatively simple.

Intramuscular injection sites include the gluteus medius in the buttocks.
Intramuscular injection sites include the gluteus medius in the buttocks.

For an intramuscular injection to be effective and safe, the muscle or muscle group needs to be reasonably large, with nerves and major blood vessels isolated so that they cannot be hit by the needle. The area cannot be painful, and the patient cannot have certain conditions such as clotting disorders which might cause complications after the injection. Methods such as oral delivery are also preferred when they are available to patients and care providers.

Intramuscular injection sites include the vastus lateralis in the thigh.
Intramuscular injection sites include the vastus lateralis in the thigh.

Four major sites on the body are commonly used as intramuscular injection sites. The first is the deltoid muscle in the upper arm. This injection site is popular because it is easy to access and patients can expose it without very much trouble by rolling up a sleeve. However, this site can be tricky because it is near a major nerve and an inexperienced administrator may place the needle incorrectly and put the patient at risk.

Other intramuscular injection sites are located in the lower body. The gluteus medius in the buttocks is one option, as is the vastus lateralis in the thigh and the ventrogluteal intramuscular injection site in the hip. When selecting injection sites, health providers think about the patient's general health, the type of medication being administered, the appearance of the available sites, and how easy it will be to perform the injection.

One advantage to using intramuscular injection sites is that a large volume of medication can be absorbed by the muscles. The distribution rate is also relatively rapid, although slower than direct delivery into the bloodstream, which can be an advantage when a doctor does not want a medication to flood someone's system. Disadvantages can include the risk of developing fibroids and other problems after repeated injections, and the risk of placing the needle improperly and injuring the patient. Learning to deliver intramuscular injections also takes a bit more training than subcutaneous injections such as those used for insulin.

The upper arm is a common intramuscular injection site.
The upper arm is a common intramuscular injection site.
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


@Bakersdozen - I'm sorry to hear that you have had several painful injections. You may have guessed that it's not an easy procedure to carry out if the care giver is inexperienced, or the patient is ultra nervous.

My opinion as a nurse is that a good intramuscular injection technique is something you have to learn though practice. Of course it is important to learn the best positioning for each site, but after that it really is a case of practice makes perfect.


I've never been given any choice about where I get an IM injection. It always seems to be in my buttock, and it usually hurts. The rare time it doesn't I am quite surprised!

It makes me wonder if nurses and doctors are actually trained in how to give an intramuscular injection. I have heard they practice on oranges and other fruit, which seems a bit ridiculous to me!


@micheller23 - When my son had to get a jab I was surprised to hear that pediatric intramuscular sites for babies under a year don't include the butt!

It makes sense that this muscle area is not developed enough until a child is walking, but the doctor said that the upper thigh is also better because it's easier to keep a baby still for the procedure.


When picking sites of intramuscular injection, it's very important to consider the receiver's body, as well. Not all these injection points are appropriate for all people -- I have to admit, I learned this the hard way in my early days as a nurse.

Some common tips are: do not inject in the rear-end on a young child, due to lack of development, and do not inject into the deltoid muscle on a very thin or underdeveloped person.

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