Deltoid

Definition

The deltoid is a large, triangular muscle covering the shoulder joint. It is commonly used as an injection site for intramuscular (IM) drug administration.

5 Must Know Facts For Your Next Test

1. The deltoid muscle can accommodate IM injections of up to 2 mL.
2. Proper needle length for deltoid injections in adults is generally between 1 to 1.5 inches.
3. To locate the deltoid injection site, find the acromion process and measure about three finger widths below it.
4. The deltoid muscle is preferred for vaccinations such as the influenza and COVID-19 vaccines.
5. Aspirating before injecting into the deltoid is not typically necessary according to current guidelines.

Review Questions

• What is the maximum volume that can be safely injected into the deltoid muscle?
• How do you locate the correct site for a deltoid injection?
• Why might the deltoid muscle be a preferred site for certain vaccinations?

Related terms

intramuscular injection: A method of delivering medication deep into muscles, allowing it to be absorbed into the bloodstream quickly.

acromion process: A bony prominence on the scapula (shoulder blade) that serves as a landmark for locating the deltoid injection site.

needle gauge: A measurement of the diameter of a needle; lower numbers indicate thicker needles, which may be relevant when selecting needles for IM injections.