Identify the correct angle of insertion for different parenteral routes?

Appeared in: GMCH - 2015

Explanation

The correct angle for an intradermal (ID) injection is between 5° and 15°.
This shallow angle ensures the medication is injected into the dermis, the layer of skin just beneath the epidermis.
A 10° angle falls within this accepted range, making it a correct technique for procedures like allergy testing or tuberculin screening.
Proper ID injection technique results in the formation of a small bleb or wheal at the injection site.

Option B: A 25° angle is incorrect for a subcutaneous injection. This angle is too shallow and may not reach the subcutaneous tissue effectively.
Option C: A 30° angle is incorrect for an intramuscular (IM) injection. This angle would deposit the medication into the subcutaneous tissue, not the muscle.
Option D: A 60° angle is incorrect for an intramuscular (IM) injection. Similar to a 30° angle, this is too shallow and would not reliably penetrate the muscle tissue.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Parenteral Injection Angles as background academic context rather than a clinical decision trigger.
Using the correct injection angle is critical for patient safety and medication efficacy. An incorrect angle can lead to improper drug absorption, nerve or bone injury, and localized pain or tissue damage.
For example, administering an IM medication into the subcutaneous tissue can delay its onset of action and cause sterile abscesses.
What if? If a nurse administers insulin (a subcutaneous medication) at a 15° angle, it would be an intradermal injection. This would cause significant irritation, a painful bleb, and very slow, unpredictable absorption of the insulin, leading to poor glycemic control.

How to Approach the Question

First, identify the core of the question, which is to find the correct statement linking an injection route to its angle of insertion.
Systematically evaluate each option by recalling the standard administration angles for the three main parenteral routes.
Recall or verify: Intradermal (ID) is 5-15°, Subcutaneous (SC) is 45-90°, and Intramuscular (IM) is 90°.
Check Option A: '10° is for an intradermal injection.' Since 10° is within the 5-15° range for ID, this statement is correct.
Check Option B: '25° is for a subcutaneous injection.' This is incorrect; the standard is 45° or 90°.
Check Options C and D: '30°' and '60°' for an intramuscular injection. Both are incorrect; the standard is 90°.

Concept Tested & Keywords

Concept Tested: Parenteral Injection Angles
Stem keywords: angle of insertion, parenteral routes, intradermal injection, subcutaneous injection, intramuscular injection
Lead-in keywords: Identify the correct

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E6 Pharmacology Nursing Lilley 11e Part 1 p. 132-134

E6 Nursing Fundamentals Potter Perry 12e Part 3 p. 173-175

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Attempt every question from this paper in a timed mock, then review the full solution for each one.