An<unk>  is performed perpendicular to the skin, close to a 90 degree angle. Comparison of angle of<unk>  with other injection types. An<unk>  can be administered in multiple different muscles of the body. Common sites for<unk>  include: deltoid, dorsogluteal, rectus femoris, vastus lateralis and ventrogluteal muscles. Sites that are bruised, tender, red, swollen, inflamed or scarred are generally avoided. The specific medication and amount being administered will influence the decision of the specific muscle chosen for injection. The injection site is first cleaned using an antimicrobial and allowed to dry. The injection is performed in a quick, darting motion perpendicular to the skin, at an angle between 72 and 90 degrees. The practitioner will stabilize the needle with one hand while using their other hand to depress the plunger to slowly inject the medication – a rapid injection causes more discomfort. The needle is withdrawn at the same angle inserted. Gentle pressure may be applied with gauze if bleeding occurs. Pressure or gentle massage of the muscle following injection may reduce the risk of pain. Aspiration Aspirating for blood to rule out injecting into a blood vessel is not recommended by the US CDC, Public Health Agency of Canada, or Norway Institute of Public Health, as the injection sites do not contain large blood vessels and aspiration results in greater pain. There is no evidence that aspiration is useful to increase safety of<unk> s when injecting in a site other than the dorsogluteal site. However, aspiration is recommended by the Danish Health Authority for COVID-19 vaccines to reduce the potential rare risk of blot clotting and bleeding. Z-track method The Z-track method is a method of administrating an<unk>  injection that prevents the medication being tracked through the subcutaneous tissue, sealing the medication in the muscle, and minimizing irritation from the medication. Using the Z-track technique, the skin is pulled laterally, away from the injection site, before the injection; then the medication is injected, the needle is withdrawn, and the skin is released. This method can be used if the overlying tissue can be displaced. Injection sites The deltoid muscle in the outer portion of the upper arm is used for injections of small volume, usually equal to or less than 2 ml. This includes most<unk>  vaccinations. It is not recommended to use the deltoid for repeated injections due to its small area, which makes it difficult to space out injections from each other. The deltoid site is located by locating the lower edge of the acromion process, and injecting in the area which forms an upside down triangle with its base at the acromion process and its midpoint in line with the armpit. An injection into the deltoid muscle is commonly administered using a 1-inch long needle, but may use a -inch long needle for younger people or very frail elderly people. The ventrogluteal site on the hip is used for injections which require a larger volume to be administered, greater than 1 ml, and for medications which are known to be irritating, viscous, or oily. It is also used to administer narcotic medications, antibiotics, sedatives and anti-emetics. The ventrogluteal site is located in a triangle formed by the anterior superior iliac spine and the iliac crest, and may be located using a hand as a guide. The ventrogluteal site is less painful for injection than other sites such as the deltoid site. The vastus lateralis site is used for infants less than 7 months old and people who are unable to walk or who have loss of muscular tone. The site is located by dividing the front thigh into thirds vertically and horizontally to form nine squares; the injection is administered in the outer middle square. This site is also the usual site of administration for epinephrine autoinjectors, which are used in the outer thigh, corresponding to the location of the vastus lateralis muscle. The dorsogluteal site of the buttock site is not routinely used due to its location near major blood vessels and nerves, as well as having inconsistent depth of adipose tissue. Many injections in this site do not penetrate deep enough under the skin to be correctly administered in the muscle. While current evidence-based practice recommends against using this site, many healthcare providers still use this site, often due to a lack of knowledge about alternative sites for injection. This site is located by dividing the buttock into four using a cross shape, and administering the injection in the upper outer quadrant. This is the only<unk>  site for which aspiration is recommended of the syringe before injection, due to higher likelihood of accidental intravenous administration in this area. However, aspiration is not recommended by the Centers for Disease Control and Prevention, which considers it outdated for any<unk> . Special populations In some populations, a change in injection site, needle length, or technique is necessary. For example, in very young people or frail elderly people, a normal length needle may be too long to safely inject in the desired muscle. For this reason, in these people, a shorter needle is recommended to decrease the risk of injecting too deep. It is also recommended to consider using the anterolateral thigh as an injection site in infants under one year old. To help infants and children cooperate with injection administration, the Advisory Committee on<unk> munization Practices in the United States recommends using distractions, giving something sweet, and rocking the baby side to side. In people who are overweight, a 1.5-inch needle may be used to ensure the injection is given below the subcutaneous layer of skin, while a -inch needle may be used for people who weigh under . In any case, the skin does not need to be pinched up before injecting when the appropriate length needle is used.
Intramuscular injection
Subcutaneous injection
Intraperitoneal injection
Subcutaneous infusion
Subcutaneous implant
Intrathecal administration
Intradermal injection
Transdermal spray