Clinical Skills - Intradermal, Subcutaneous, and Intramuscular Injections

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In this video and article, we explain intradermal vs. subcutaneous vs. intramuscular injections. What they are, when they're used, needle size, injection volume, and how to administer. We highly recommend watching the video to see Ellis demonstrate the physical techniques. We'll start off with some background on needle sizes.

The Clinical Skills video series follows along with our Clinical Nursing Skills Flashcards, which provide step-by-step instructions and best practices for most skills used by practicing nurses and for the skills tested by most nursing schools during the laboratory portion of fundamentals.

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Needle size basics

What's the difference between a needle's gauge and size? We'll explain below.

Note that when you are experiencing different types of needles in a clinical setting, a needle’s gauge and size (length) are defined in a single measurement. For example, “25G 1/2" refers to a 25-gauge, 1/2-inch-long needle.

Needle gauge

A needle’s gauge refers to the size of the hole in the needle. If you are familiar with the world of ear piercings, this is the same meaning of the word gauge! The most common needle gauges are 18, 20, and 22. Choosing the correct gauge size depends on the type of medication to be administered.

Needle length

The length of a needle varies, depending on the type of injection to be administered and where on the body the injection will be given.

Intradermal injections

An intradermal injection is an injection administered into the dermis, just below the epidermis (skin). It is a shallow or superficial injection of a substance, providing a local versus a systemic effect.

When is an intradermal injection used?

Intradermal injections may be used for diagnostic purposes, e.g., allergy or tuberculosis testing.

Intradermal injection needle size

When choosing a needle size, use a 25- to 27-gauge needle, between 1/4 and 1/2 inch in length.

Intradermal injection volume

Only a small amount of medication is administered through this route, under 0.5 milliliters.

Steps for administering an intradermal injection

To administer an intradermal injection, select a site (it's almost always the forearm) and cleanse the site with an antiseptic swab. Spread the patient's skin taut with the thumb and index finger of your non-dominant hand.

Apply the needle bevel-up at a 5- to 15-degree angle, then advance the needle until the bevel is just under skin. Do not aspirate once the needle is inserted.

Slowly inject the medication to form a small bleb (bubble) or wheal under the skin, then remove the needle quickly at the same angle of insertion.

Note that we do not massage the site after removing the needle.

Subcutaneous injections

A subcutaneous injection is a type of injection, using a short needle to inject a drug into the tissue layer between the skin and the muscle.

When is a subcutaneous injection used?

Subcutaneous injections are used to administer larger volumes of medication that may take longer to be absorbed, such as insulin, morphine, diacetylmorphine, and goserelin.

Subcutaneous injection needle size

For subcutaneous injections, use a 25- to 30-gauge needle, which may vary in length between 3/8 and 5/8 of an inch.

Subcutaneous injection volume

The volume of medication in a subcutaneous injection is less than 1 milliliter.

Steps for administering a subcutaneous injection

Perform the injection in a fatty area of the body, for example the abdomen or upper lateral arm. Cleanse the site with an antiseptic swab

It is important to rotate injection sites to reduce the risk of developing lipohypertrophy (when lumps of fat or scar tissue form under the skin) and give the skin a chance to heal.

Pinch the skin to create a skin fold using your non-dominant hand. Insert the needle at a 45-degree angle for patients with less than 1" of pinchable fat, and 90 degrees for patients with more than 1" of pinchable fat.

The reason for the difference in angle is that in a patient with more fat, it is safe to use 90 degrees to reach the subcutaneous layer under the skin; in a patient with less fat, at 90 degrees you run the risk of the needle going too far and going into the muscle—a 45-degree angle decreases the likelihood of that happening.

After the needle is inserted, release the pinched skin and inject the medication using your dominant hand. Remove the needle at the same angle of insertion.

Note that we do not massage the site after removing the needle.

Intramuscular injections

An intramuscular injection (IM) is a technique used to deliver a medication deep into the muscles, allowing medication to be absorbed into the bloodstream.

When is an intramuscular injection used?

Intramuscular injections are used to deliver vaccines and other drugs.

Intramuscular injection needle size

For an IM, use a 20- to 25-gauge needle, which may vary in length between 1/2 to 1.5 inches in length. The needle is longer than those used in intradermal and subcutaneous injections because it has to penetrate the epidermis, the dermis, the fat tissue, and the subcutaneous tissue to deliver the medication into the muscle.

Intramuscular injection volume

The volume of medication will vary: for children under 2-years old, the maximum volume should be less than 1 milliliter; for adults, the maximum volume is less than 1 milliliter for the deltoid muscle and less than 3 milliliters for the vastus lateralis (outer quad muscle) and ventrogluteal (outside hip).

Steps for administering an intramuscular injection

It is important to choose the right muscle for an IM. For infants, use the vastus lateralis muscle. For older children and adults, use the ventrogluteal site or the deltoid site. Note that the dorsogluteal site is rarely used for an IM injection due to the risk of sciatic nerve damage with those injections.

In the video, Ellis demonstrates a great triangulation technique for locating the ventrogluteal site on the patient.

Cleanse the injection site, then stabilize the injection site with your non-dominant hand. Insert the needle at a 90-degree angle using your dominant hand. Stabilize the syringe with your non-dominant hand.

Inject the medication at a slow and even pace. Remove the needle at the same angle of insertion. Apply bandage or gauze to the injection site.

Note that we do not massage the site after removing the needle.

Z-track method

Occasionally a medication must be administered that can stain the tissue, for example iron dextran (an iron supplement). In this situation, we use the Z-track method:

  1. With the ulnar side of your non-dominant hand, gently laterally displace (push to the side) the skin by 1".
  2. Insert the needle and inject the medication with your dominant hand.
  3. Remove the needle.
  4. Release the skin, and let it fall back in place on its own.

Full Transcript: Clinical Skills - Intradermal, Subcutaneous, and Intramuscular Injections

Hi, I'm Ellis with Level Up RN. In this video, I'll be demonstrating how to perform injections. I'll be doing intradermal injections, subcutaneous injections, and intramuscular injections. I'll be following along on the steps that are included in our Clinical Nursing Skills deck. So if you have the deck, grab these cards. If you don't have the deck, head on over to LevelUpRN.com to check one out.

Intradermal injections are almost always done on the forearm, so that's what we'll be practicing with today. So after you select your site, you're going to clean it with an antiseptic swab, starting in the center and moving out. And as that's drying, I'm going to go ahead and grab my syringe. So I'm always going to use a very small gauge needle. I'm going to position it so that the bevel is up. I want the bevel up because for intradermal injections, I want the bleb to form, which can also be called a wheal or a bubble, right? When you get that TB shot, you've got that little bubble that forms. If my bevel is not up, which allows the medication to be injected up into that first layer of tissue, if the bevel is down and I inject the medication down, it won't form the bleb that I'm looking for. So with my bevel up and with my hands kind of high on the syringe itself-- meaning I don't want to grip it really low. I don't want to hold it like a dart like I would for an IM. I want to hold it rather high because I need to go at a really low angle, and I don't want my fingers in the way.

So I'm going to pull the skin taut with my thumb and forefinger of my nondominant hand. Holding my syringe with my fingers on top of it with my bevel up, I'm going to inject at a 5- to 15-degree angle slightly under that skin. Once the full bevel is under the skin, I can then inject the medication, hoping for that bleb to form. And mine is not really cooperating. Once that's done, I withdraw it at the same angle. And with these, it's really imperative that I do not massage the site in any way because then that might disperse that medication into different layers of tissue. And that's how I do my intradermal injection.

In preparing for my subcutaneous injections, I've already done my hand hygiene and donned gloves. I then need to select the site that I'm going to be using, and this can be any site that has a surplus of subcutaneous tissue or fatty tissue, right? So the most common areas are going to be on your tummy, so I've got my little belly friend here today. So on your tummy, on the backs of your arms is good, although difficult to do to yourself. And then the lateral aspects of your thighs can also be an option. So we'll be using the abdomen today. I've already gotten an insulin needle drawn up with some insulin. So I'm just going to go ahead and use an antiseptic swab to clean in a circular motion starting where my injection is outward and allow that to dry. If my patient has at least one inch of pinchable fat, meaning they've got a little bit extra going on, then I can go in at a 90-degree angle. If they do not have the extra subcutaneous fat, then I am going to want to go in at a lower angle, at a 45-degree angle, because if they are not blessed with extra subcutaneous tissue and you go in at a 90-degree angle, you have an increased likelihood of hitting that muscle. You don't want the needle to go into the muscle. This medication is for subcutaneous injections. So you might want to decrease that insertion angle if that's needed.

So I uncapped my needle. I'm actually going to pinch the subcutaneous tissue up, which is, again, a little bit difficult on these mannequins. But as well as I can, I'm going to pinch it up. I'm going to go ahead and do a 45-degree angle for this guy. So I'm going to insert my needle. I'm going to let go of the pinch. I'm going to inject my medication and then take the needle out at the same angle that I inserted it. I then immediately waste this needle into my sharps box, and then I can apply a piece of gauze or a bandage if needed. But like all of my other insertable medications, I do not massage the site. I just let it be. And he's gotten his insulin.

My first demonstration of an intramuscular injection is going to be in the vastus lateralis site, and I'm going to be using just the general injection method. So I've got my patient here. This is his rear end, right? I'm going to locate my site using those anatomical landmarks. So I'm going to place the palm of my hand on the greater trochanter. I'm going to point my middle finger straight up towards his iliac crest. I'm going to dip my first finger forward towards his groin. And this is my triangle of safety. So this is where I would want to inject my medication. So once I determine the injection site, I'm going to get a antiseptic swab. I'm going to go in concentric circles. And as that's drying, I'm going to grab my syringe and needle. I've already drawn up about a milliliter of medication. I'm going to take my cap off, and then I'm going to go ahead and pull the skin taut so that it's not moving around while I go for the injection. I like to hold these needles, when I'm doing an intramuscular injection, kind of like I would dart. I feel like I have a lot of control over the syringe when I do that. I don't feel like I'm going to be wiggly when I insert the needle, and I want to make sure I go in at that 90-degree angle. So that's straight up and down, perpendicular, right? Because I need this needle to make it all the way down through the layers of tissue into the muscle. If it doesn't make it into the muscle, I have injected a medicine that's for muscular tissue into something else like subcutaneous tissue.

So I'm going to pull that skin taut. I'm going to inject it, insert it at that 90-degree angle. At this point, I like to suggest to students sometimes to use these fingers to go ahead and anchor this. Sometimes when you're new or a little nervous, you tend to wiggle a little bit like that. And as you can imagine, that would be very uncomfortable for your patient. So if you wanted to, you could move these fingers up to stabilize this while you come up to the actual plunger and inject the medication. So I've injected my medication slowly and steadily. And then I'm going to withdraw it at the exact same angle at which it was inserted so that I don't increase that wound track, and I'm going to immediately waste into a sharps box so that I'm following those precautions.

All right. I'm going to just set this aside. And I'm going to show you the other method for intramuscular injection, which is the Z-track method. I'm going to use this little guy. I know he's not as realistic, but he does move a little bit more. I don't know why it's a he, but he moves a little bit more, whereas that model is more solid. I want to show you that the Z-track method is to displace the upper layers of tissue. So if I'm using the Z-track method on an intramuscular injection, I'm going to select my site, right, using my anatomical landmarks just like before. I'm going to clean it with my antiseptic swab starting at the center, moving outward in concentric circles. All right. While that's drying - again, all these steps are the same - I'm going to go ahead and grab my needle with my syringe. I've got the medication prepared. And then what we do here is we use the side of our nondominant hand to actually push down and displace those first layers of tissue. I'm going to follow the same rules of injecting at a 90-degree angle. I'm going to insert my medication slowly and steadily. I'm going to withdraw at the same angle, and then I let go. And all of that displaced tissue that I've moved laterally about one inch moves back over. So now instead of the would track being straight up and down, the wound track is kind of like this, and it's less likely for any medication to seep into other tissue or even out of the wound track.

This particular type of needle has a safety method. And so if you're using safety needles, you, of course, want to immediately employ that. So I can just-- you saw that needle? It shot back into the syringe. And I would still need to immediately take that and put it in a sharps box. That's how you do intramuscular injections.

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