I did not write this, I am only posting it because I though it would be a good newb thread.

Original thread: Intramuscular Injection: A helpful guide - Science of Muscle Forums

Quote Originally Posted by LakeMountD View Post
Okay well I am not on the forums as much as I used to but when I was I would constantly see how much misinformation gets thrown around, especially when it came to intramuscular injections. I wanted to give some information regarding intramuscular injections and a few tips that can help you avoid problems.

Firstly there are 3 main areas of intramuscular injection: vastus lateralis, gluteus maximus, and the deltoid. There are other places of course, however, you should stick to these as they are proven safe and avoid major nerves. When injecting into a muscle you want to avoid a nonlinear path. Many times people inject really slow and have somewhat of a shaky hand which can cause an uneven path which leads to greater pain and inflammation. Of the three sites above the most effective is typically the gluteus maximus as it can take the largest amount of solution (or suspension for that matter), but you must be sure to inject in the correct place. There are two sites in the gluteal muscle, one of which is dorsogluteal and the other is ventrogluteal. Most commonly people use the dorsogluteal, which is okay if you actually study what you are doing but is far more dangerous for people new to IM injection as it runs dangerously close to the sciatic nerve. The sciatic nerve is the major nerve running into your legs and even if you just nick it, could lead to numbness or permanent loss of function, not something you want to mess with. Here are a few pictures of the two spots for gluteal IM injection:




The gluteal site also has the slowest rate of perfusion and the highest fat content which allows for the most steady release. The vastus lateralis also has somewhat poor perfusion but due to the low fat content, the lipophilic steroids typically stay as a large mass, again allowing for steady release into the bloodstream. The deltoid provides a site with the highest perfusion and the fastest rate of onset depending on what you are looking for. Remember that a relaxed muscle typically causes less pain and inflammation after injection than a flexed muscle so resting your arm on table can help prevent flinching and movement. Same goes for your v. lateralis or g. maximus. Be sure to be in flexed position but not actually flexing. For instance you wouldn't want your leg to be in a hamstring flexed position when injecting into the vastus lateralis. Here are some pictures of where these injection sites are:


Volumes also vary for each muscle group. You don't want to exceed ~4-5mL in either buttock at once and no more than ~2mL in either deltoid at once. This can help prevent inflammation or infection, which can lead to cyst formation.

Now that you have learned the sites of injection let's go into actual injection procedures. THE MOST IMPORTANT thing in IM injection is sterility and aseptic technique. We want to be sure that no bacteria are introduced into the body which, if local, can lead to cellulitis, or if stystemic could lead to septicemia and possible septic shock. Your skin is teaming with bacteria and you must be sure that the area of injection is completely clean. Your skin provides an excellent barrier to bacterial entry but a needle can push these bacteria directly past the skin barrier and into endogenous areas. This means that injection after a workout or after a long day at the office is out of the question. Most people become flexible with these rules and eventually get a cyst, which must be removed surgically.

Follow these steps to ensure proper aseptic technique and injection procedure:

1. Locate site of injection before doing anything.
2. Wash the site of injection with soap and water, scrubbing hard. If you just got out of the shower you can skip this step.
3. Once you wash the site don't continually touch it as this will just introduce new bacteria to the area.
4. Open an alcohol swab and swab the rubber stopper from bottom to top 3 times. Do not use circular motions as some bacteria are highly resistant and wiping top to bottom can help remove them without just moving them around.
5. Take the syringe and needle out of the wrapper and apply the needle to the syringe. Be sure not to touch the needle because it must remain sterile. Pull back on the plunger until you have as much air in the barrel of the syringe as you want to inject. For instance if you want to inject 2 mL of solution make sure you have 2 mL of air in the syringe.
6. Turn bottle upside down and inject the needle into the stopper. Depress the plunger so that the air is in the bottle. Be sure the tip of your needle is below the fluid line so you don't drawn in more air.
7. Pull back on the plunger and draw the desired amount of liquid into the syringe. Take the needle out of the stopper and hold the syringe needle side up. Flick the side of the syringe to make whatever bubbles that are in the syringe go to the top. This is a very important step that will be explained below. Once all the bubbles have gone to the top, slowly depress the plunger with the needle still up and push the air out of the syringe. Also allow a little bit of solution to flow out slowly over the syringe as this will further lubricate the needle.
8. DO NOT use alcohol on the needle itself, it is already sterile and doing this will remove the silicone coating that helps in the needle sliding into the muscle. Set the syringe down with the needle cap on and use another alcohol swab to prepare the injection site. Once again use a sweeping motion in one direction pressing hard. You want to be sure to get the resistant bacteria off the skin by wiping away a small skin layer.
9. Push the needle into the skin in a relaxed position but BEFORE YOU DEPRESS THE PLUNGER make sure you actually pull slightly back on the plunger (.25 mL or so) and be sure that no blood comes into the syringe. This tests to make sure you have not hit a vein. You should see a small air bubble appear. If you see blood pull the needle out, put a new needle on and try again in another **********
10. If no blood is present inject in a medium fashion over the course of about 10 seconds or so.
11. Pull the needle out BE SURE TO CAP IT SO NO ONE GETS STUCK and throw it away.

Why is it important to check to see if a vein was hit? Oil is lipophilic and does not mix with water. When an oil is injected into the blood stream (a vein) it acts as an embolism which can lodge into small capillaries and cause serious problems. In a vein the first place an embolus usually encounters is the pulmonary circulation (lungs). Here it gets lodged and can cause infarction/necrosis (death of tissue) upstream. The same goes for air bubbles, they are not soluble and can cause similar issues.

Filtering liquids retrieved from a glass ampule. The biggest mistake I see from people is using something like hCG from a glass ampule and directly injecting it. Something that they seem to forget is that even though you don't see any glass shards it does not mean they are not there. When breaking a glass ampule and using its contents it must be filtered with at least a non-sterilizing filter that is 1-5 um. Failure to do this can lead to inflammation of tissue that when used long term can cause issues, especially if accidentally injected into a vein. If injected into a vein phlebitis (inflammation of vein) can occur.

That is the end for now. If you have any questions ask and remember be safe and KEEP ALL AREAS STERILE.