Intramuscular injection is usually in the hip, lateral thigh and deltoid muscle of upper arm. Subcutaneous injections can be made around the navel. There is no examination for drawing intestinal fluid.

Subcutaneous injection means not injecting into the muscle layer, which can also be simply understood as not very deep. If you don't want to inject into the muscle layer, you can inject vertically or at a 45-degree angle, but it is not recommended to inject yourself.

I haven't tried navel injection, even if I do, it should be useless, because the medicine can't be absorbed there.