Administering an intramuscular injection
here to see a demonstration
An injection is
a method of putting liquid into the body with a hollow needle and a syringe
which is pierced through the skin to a sufficient depth for the material to be
forced into the body. An injection follows a parenteral route of injection, that
is, its effect is not necessarily local to the area in which the injection is
administered; it is systemic.
There are several types of injections or infusions, including, subcutaneous,
intramuscular, and intravenous infusions.
The gluteus medius muscle, which is also known as the
ventrogluteal site, is the third commonly used site for IM injections. The
correct area for injection can be determined in the following manner. Place the
heel of the hand of the greater trochanter of the femur with fingers pointing
towards the patient's head. The left hand is used for the right hip and vice
versa. While keeping the palm of the hand over the greater trochanter and
placing the index finger on the anterior superior iliac spine, stretch the
middle finger dorsally palpating for the iliac crest and then press lightly
below this point. The triangle formed by the iliac crest, the third finger and
index finger forms the area suitable for intramuscular injection.
Intramuscular injection is the injection of a substance directly
into a muscle. In medicine, it is one of several alternative methods for the
administration of medications (see Route of administration). It is used for
particular forms of medication that are administered in small amounts. Depending
on the chemical properties of the drug, the medication may either be absorbed
fairly quickly or more gradually. Intramuscular injections are often given in
the deltoid, vastus lateralis, ventrogluteal and dorsogluteal muscles. When the
gluteal muscles are used, injections should be made on the upper, outer quadrant
of the buttock to avoid damaging the sciatic nerve. Injection fibrosis is a
complication that may occur if the injections are delivered with great frequency
or with improper technique.
Thrombocytopenia (low platelet counts) and coagulopathy
(bleeding tendency) are contraindications for intramuscular injections, as they
may lead to hematomas.
Examples of medications that are sometimes administered
* Interferon beta-1a
* sex hormones, such as testosterone, estradiol valerate, and
* quinine in its gluconate form
In addition, some vaccines are administered intramuscularly:
* hepatitis A vaccine
A subcutaneous injection is administered as a bolus into the
subcutis, the layer of skin directly below the dermis and epidermis,
collectively referred to as the cutis. Subcutaneous injections are highly
effective in administering vaccines and such medications as insulin.
Intravenous is a term that means within the vein. An injection
is something that is introduced into something else. An intravenous injection is
the introduction of a substance into the veins using a needle. This may be
necessary for medical reasons. It may also be done for illicit purposes.
An intravenous injection can involve one or more single doses of
a substance administered through a needle. The substance to be administered is
usually stored in a syringe, which is attached to the needle. Once the needle is
inserted into a vein, the raised portion of the syringe may be depressed,
forcing the substance into the vein.
Intravenous injection can be a means of therapy in some other
medical cases. Sometimes, such as in cases of dehydration, a person is given
fluids intravenously over an extended period, which could be hours or days.
Instead of syringes, the substance to be injected is often stored in bags hung
above the patient. The substance flows through tubes to the needle. Gravity is
the force that is generally used to make this possible. The flow is generally
controlled by clips that can be connected to the tube that runs to the needle.
Doing this is a means to quickly replace fluids the body needs.
This method of treatment may be referred to as a drip or an IV. Blood
transfusions and intravenous feeding may also be administered in this way.