by Patrice La Vigne
Drug and biological product administration via intramuscular injections using hypodermic needles has been a common medical practice for several centuries and is not going anywhere soon—from vaccines, antibiotics and insulin to an experimental injectable male contraceptive in development.1 The main issue with intramuscular injections is that if the hypodermic needle containing the drug or biological is injected incorrectly into a muscle or another part of the body, it could cause serious harm.
Hitting the Sweet Spot
Once administered exclusively by physicians, nurses began to take on the duties of giving intramuscular injections starting in the 1960s as children were being injected with an increasing number of vaccines. Normally, injection sites are focused on muscle areas and, depending on the formulation, the drug or biological is then absorbed into the bloodstream quickly or gradually.
Doctors and nurses administer vaccines in four different muscular areas: deltoid muscle of the arm, vastus lateralis muscle of the thigh, ventrogluteal muscle of the hip and the dorsogluteal muscle of the buttocks.2 And while it does depend on the agent injected, specific injection sites can decrease the risk of injection-related injuries. The first rule of thumb is that shorter, higher gauge needles minimize complications.
Secondly, guidelines recommend administering shots in the upper outer quadrant of a person’s buttocks: the ventrogluteal muscle of the hip. It provides the greatest thickness of the gluteal muscle and is free of penetrating nerves and blood vessels. It also has a narrower layer of fat.
The dorsogluteal muscle of the buttocks, on the other hand, is linked with a higher risk of sciatic nerve injury (lower back, hip, back of leg). The deltoid site is commonly used in outpatient settings, however there is a need for caution because of the close proximity of the bone, radial nerve and brachial (shoulder to elbow) artery.