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How and where is a deltoid IM injection given?

Medically reviewed by Carmen Pope, BPharm. Last updated on Nov 30, 2021.

Official answer


A deltoid IM injection is given into a specific area of the deltoid muscle located in your upper arm. Many vaccinations are given by this route. There are several different ways to find the deltoid muscle injection site, which is the central and thickest portion of the deltoid muscle, for example:

  • Find the acromion process, which is the bony bit that sticks out from your shoulder, just above the deltoid muscle. Approximately 2–3 fingerbreadths (approximately 2 inches) below the acromion process, and sitting just above the level of the armpit, in the central part of the upper arm is the deltoid injection site
  • Find the intersection of an imaginary line drawn between the anteroposterior axillary line and a perpendicular line from the mid-lateral of the acromial process (imagine where a line drawn from the middle of the acromion process would bisect a line drawn across the top level of the armpit).

To aid identification of the muscle area, you can ask the person to raise their arm first to define the muscle. Once defined, have the patient relax their arm and proceed.

To avoid causing an injury, do not inject too high (near the acromion process) or too low (which may miss the muscle).

How do you give a deltoid IM injection?

  1. Locate the deltoid injection site, as described above.
  2. Use a needle long enough to reach the deep muscle. For vaccinations in adults, this is usually a 22–25-gauge needle which is 1 inch (25mm) long for those weighing less than 70kg (154lbs), 1 to 1.5 inches (25-38mm) long for those 70-90kg (154-198lbs), and 1.5 inches (38mm) long in those more than 90kg (198lbs).
  3. Use your thumb and index finger to stretch the skin around the injection site.
  4. Insert the needle with a deep thrust at a 90-degree angle to the skin (straight up and down). Aspiration is not necessary or recommended. Push down on the plunger of the syringe slowly, then withdraw the needle once all the contents have been administered.
  5. Apply a plaster or wound pad to the area if there is any bleeding.
  6. If you are giving two deltoid IM injections into the same arm, separate them by a minimum of one inch.

Do you pinch the skin when giving a deltoid IM injection?

No, you should not pinch the skin if you are giving a deltoid IM injection because this may mean you inject the syringe contents into the subcutaneous tissue rather than the muscle.

What angle do you give an IM deltoid injection?

You should insert the needle at a 90-degree angle to the skin (straight up and down) to ensure it gets into the deltoid muscle.

  • Vaccine Administration: Needle Gauge and Length. 08/04/2020.
  • How to Administer Intramuscular and Subcutaneous
  • Vaccine Injections to Adults
  • How to Administer IM (Intramuscular) Injections
  • Shoulder injury related to Sinovac COVID-19 vaccine: A case report
  • Chuaychoosakoon C, Parinyakhup W, Tanutit P, et al. Annals of Medicine and Surgery
  • Volume 68, August 2021, 102622

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