Injection in general is a type of medical procedure of introducing a fluid into the patient's body. The infusion of the liquid in to the body governs certain actors such as the depth, amount, location and need. Injections are usually administered in order to direct the drug to its function rather than through the digestive tract.
There are different kinds of drugs based on its effectivity. Injecting the drug to a specific location in the body is done in order for the function of the drug be maximized. If the medical person injects a drug to wrong location, the drug may not be utilized well and can even produce side effects in the patient.
There are different kinds of injections depending on the medical needs of the patients. Injections are classified to the depth infusion. This includes:
- Intradermal - layers of the skin (for allergy treatment, anti-tetanus, tuberculosis)
- Intramuscular - direct infusion to the muscle for rapid absorption of the medicine (Vaccines and hormones).
- Subcutaneous injections - when medicine should be absorbed slowly.
- Intravenous - directly to the veins
Some injections like anaesthesia are infused directly to where it is needed (e.g. tooth extraction, surgery or amputations).
Injections are given in different parts of the body, and at different depths, for important medical reasons. Depending upon the type of injection, it may optimally need to be administered in the arm, and, in the case of some injections, for example, influenza vaccines, specifically in the upper arm. Other injections, mainly insulin injections for diabetics and, before the introduction of newer, less painful regimens, rabies injections, are administered in the abdomen. The reason for these distinctions is that different inoculations occur for different reasons, and the precise medication involved may work best if injected at specific locations.
In general terms, inoculations occur in one of three main categories: subcutaneous, intramuscular, and intradermal. Subcutaneous refers to injections into the fatty tissue between skin and muscle; intramuscular refers to injections into the deltoid muscle of the shoulder, or into the buttocks; and intradermal refers to injections into the skin, usually at an angle so as to avoid deeper penetration, as are used for intravenous injections of saline solution to rehydrate dehydrated patients. Some medications need to be delivered at greater depths, and directly into affected areas. Injections into the knee involving cortisone, or hyaluronate to treat osteoarthritis, for instance, are administered drectly into the affected joint with long and sometimes broad-gauge needles. Tuberculosis tests, on the other hand, involve intradermal injections. Again, it all depends upon the nature of the illness, the type of medicine being injected, and sometimes the preferences of the patient. Avenue into the blood stream might be the priority, or directly into diseased or damaged tissue. The arm, the abdomen, the buttocks, and the thigh are all used for injections depending upon the type of medication and the physician's determination of the optimal site for the individual patient.