Safe intramusclar injection: aspiration and sites
Most AAS injections mean pushing several millilitres of oil excipient deep into the muscle.
This is different from the small 0.5 or 1 ml isotonic water-based vaccines or inoculations injected into a shoulder at a GP’s surgery.
Even if isotonic water-based solutions (like saline) enter a blood vessel no harm occurs.
But any amount of oil excipient entering a blood vessel can cause an embolism.
A significant number of guys using AAS experience a minor embolism without recognizing what it is.
Excipient entering the blood stream typically causes some clotting; a clot can travel to the lungs where it becomes lodged – an embolism – blocking the blood supply.
Symptoms can come on almost immediately, or later, but usually within a minute or so – the time it takes for blood to flow from the quads, say, to the lungs.
The symptoms are hot flushes, pins and needles, coughing, tight chest, difficulty breathing, panic, dizziness, fainting and loss of consciousness.
Fainting carries the risk of physical injury during collapse.
A small embolism caused by only a small amount of gear (~1 ml) may disperse quite quickly and the symptoms subside. There may or may not be any lasting damage to the lungs.
But if the embolism is serious it may travel to the heart or brain, resulting in heart attack, stroke and consequent disability or death.
The safeguard against an embolism is ASPIRATION: pulling back slightly on the syringe plunger once the needle is at the correct depth in the muscle and before injecting: any blood entering the syringe shows that the needle tip is in a blood vessel and that it is NOT safe to inject.
Only a very slight, brief back-pressure on the plunger is required to clearly show any blood.
A good technique is, once the needle is inserted to depth, to pull it back outwards just a couple of mm and then hold its top firmly with the free hand. This opens the needle tip making aspiration easy and clear, and also helps avoid pushing the needle further in and into a bloodvessel.
Aspiration can be mastered with one hand when self-injecting, but usually requires both hands.
Therefore the safest injection sites for self-injection are those where both hands can be used: the quads and the pecs.
Glutes and delts, etc. are convenient for injection by others, but not easy or safe for self-injection.
Like all muscles the glutes carry important arteries, veins and nerves at various locations and depths. You are no less likely to contact a blood vessel or nerve injecting into the glutes than into other muscles.
In intramuscular injection the needle tunnel should always be about 1 inch into all muscles, so that no “blow-back” of the gear occurs during injection, and that it does not end up just under the skin.
In quads and other big muscles this means inserting the needle perpendicular to the skin – upright – until the tip is an inch into the muscle.
In the pecs and other shallower muscles it is permissible to insert the needle at an angle of about 45º so that the needle tunnel is an inch long but its tip is in the centre of the muscle belly.
It is considered a good technique by many medics not to insert the needle all the way in to the fitting: this may have been in case of breakage, or not to push any pathogens into the wound. In any case, modern needles are extremely difficult to break.
So because in IM injection insertion of the needle is always to about an inch, and allowing for any fat under the skin, 1-1/4 inch or longer needles are always suitable for all muscles.