Injection Sites and Techniques on the NCLEX
IM and subQ sites, needle lengths and angles, Z-track, and what not to massage.
Right site, right needle, right angle. Injection questions are checklists, and the details are the answer choices.
IM sites
Ventrogluteal: the preferred adult IM site. Free of large nerves and vessels; find it with your palm on the greater trochanter, fingers toward the iliac crest. Deltoid: small muscle; 1 mL max (vaccines commonly 0.5 to 1 mL). Two to three finger widths below the acromion. Vastus lateralis: the site for infants and an option in adults. Dorsogluteal: avoid it. Sciatic nerve territory. Adult IM volume generally tops out at 3 mL in a large muscle.
Needles and angles
IM: 90 degrees, needle commonly 1 to 1.5 inches, gauge suited to the drug's viscosity (often 20 to 23). Choose length by the patient's muscle mass and adipose depth; a needle that never reaches muscle gives a subQ dose of an IM drug. SubQ: 45 to 90 degrees, 25 to 30 gauge, 3/8 to 5/8 inch; 90 degrees if you can pinch a solid inch of tissue, 45 if not. Intradermal (TB test): 5 to 15 degrees, bevel up, forming a wheal on the inner forearm.
Z-track
For irritating or staining IM drugs (iron dextran is the classic), and a reasonable default for IM injections. Pull the skin 1 to 1.5 inches laterally, inject, wait about 10 seconds, withdraw, and release the skin. The displaced tissue layers seal the track so the drug cannot leak back and stain or irritate. Do not massage a Z-track site.
SubQ specifics and what not to massage
Insulin: abdomen absorbs fastest and most consistently, staying 2 inches from the umbilicus; rotate within a region rather than hopping regions day to day; no aspiration, no massage. Heparin and enoxaparin: abdomen, no aspiration, and never massage; massaging causes bruising and hematoma. Do not expel the air bubble from a prefilled enoxaparin syringe. Aspiration for IM injections is no longer routine for vaccines; follow policy for other drugs. Rotate all repeated-injection sites to prevent lipohypertrophy and tissue damage.
Frequently asked
Best IM site for a 2 mL antibiotic in an adult?
Ventrogluteal. Safe landmark profile and handles standard IM volumes.
Why no massage after heparin?
Massage spreads the anticoagulant through the tissue and causes bruising and hematoma formation.
Angle for a subQ injection in a thin patient?
45 degrees with a short needle. Choose the angle by pinchable tissue depth.
Quick check
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