Muscles you may inject into are: vastus lateralis (the outer side of thigh), gluteus maximus (your buttock but you've got to know what you do here!), biceps brachii (speaks for itself), deltoid muscle (this is the muscle closest to your arm, it's quite big, it's also on your back but if you're not experienced with i.m. injecting it's best to avoid it, vaccines are injected into this muscle), and if you work out, triceps brachii should be big enough.
Needles used for i.m. injections are 0.6mm to 0.8mm (the thicker ones are for oily solutions; needles also vary by length, e.g. there exist two variants of 0.6mm needles), and syringes used for i.m. injections can be 2ml, 5ml, or even 10ml (they're bigger so it's maybe more comfortable to hold them at the beginning but both 2ml and 5ml syringes have additional space for aspiration - pulling back the plunger to check for blood presence).
1. Firstly, you need to clean the spot, you may use salicylic alcohol or isopropanol spray, when you're about to give a wipe to the spot with a swab, do it just
ONCE and in
ONE direction, otherwise it'll be like wiping the spot with a swab bacteria are on.
2. Relax your muscles. Use your index finger and your thumb to tighten the skin around the spot.
3. Aim always at 90 degrees. When you hit the spot, you will feel puncturing your skin of course, then you should feel you punctured deeper skin, and then it's muscle (I'm talking about your thigh now, because in other spots, it's not felt that good). You should aim and hit fast.
4. Once you're in, slowly pull back the plunger (this is called "aspiration") to see if you didn't hit a vein by chance; if there's blood, pull out the needle and exchange it. If you aspirate no fluid or gas, you're in the muscle and you may slowly start pushing the plunger. You should feel when you're doing it too fast.
5. When you're done, pull out the needle and let your fingers, this should lessen any bleeding from small veins you probably won't be able to miss.
6. Apply some pressure to the spot with a swab with something like salicylic alcohol on it.
What happens during an i.m. injection is the solution you inject creates something like a spherical space from where the water is absorbed by your body into the muscle. Muscles have a lot of water in them, that's why the water solution is taken up so fast. Anyway, it's important that you don't inject more solution than you may inject in various muscles to avoid abscesses.
http://nursing.goo-done.com/t1362-topic
This is what I've just found looking for some pictures showing the part of the buttock you should aim at. Scroll down and you will see the spots for i.m. injection and how to do it. There are a lot of sites giving advice how to perform an i.m. injection. You may also want to visit
http://www.drugs.com/cg/how-to-give-an-intramuscular-injection.html, I guess it's described how to do an i.m. injection simply in plain words.
- Vastus lateralis (located on the outer side of thigh): the spot you want to aim for is the middle third of the
outer side of your thigh
Maximum volume that can be injected into: 5 ml
- Dorsogluteal muscles (it's gluteus maximus actually, upper outer sides of your buttocks): Divide your buttock into 4 parts like there was a cross on it, then again divide the upper outer quadrant the same way - the spot you want to aim at is the
upper outer quadrant after the
2nd division; if you try to inject e.g. in the
middle of your buttock, you may hit a
big artery, the very same artery you might hit, trying to hit the inner side of thigh
Maximum volume that can be injected into: 5 ml
- Biceps brachii: if you tense your biceps, you will see where it is located, then relax your muscles, and aim in the middle but avoid spots you see small veins are located under the skin
Maximum volume that can be injected into: 3 ml
- Deltoid: again tense your muscles to see your deltoid exactly, the spot you want to aim at is like you stood at attention and you see this muscle when you turn your head left or right by 90 degrees
Maximum volume that can be injected into: 3 ml
- Tricepsi brachii: back of your arm, this muscle is longitudinal, behind the biceps; but if you're skinny, then you would have to really know your body to know how deep to go in, if you work out, the muscle should be quite big; the spot you want to aim at is the upper part
Maximum volume that can be injected into: 3 ml
- Trapezius: these are located on both sides on your upper back but due to the location of them, you want to avoid them
You should be able to find the map of human body with muscles
http://en.wikipedia.org/wiki/Muscle. Then you can just google various muscles names. Also, there's a good technique to stop bleeding right away after pulling out the needle, it's called "Z-track" but I'm just falling asleep in front of my laptop. You should definitely find info on it on the net.