Subcutaneous Injections

General Information

Subcutaneous Sites:

Anterior View

Posterior View

Indications for Subcutaneous Injections:

The onset of action for subcutaneous ( SC, SQ) injections is usually slower than for intramuscular (IM) injections (heparin is absorbed as quickly when given SC).

The medications given SC are isotonic, nonirritating, and water-soluble; examples are epinephrine, insulin, heparin.

The dosage that can be given SC is less than 1 ml.


The amount of adipose tissue determines the needle length and angle of insertion. Use what is needed to deliver the medication into the subcutaneous tissue.

In general, a 25g, 5/8 inch needle is inserted at a 45-90 degree angle. The needle-length should be 1/2 of the depth of the skinfold. A rule of thumb is that if the skinfold depth is 2 inches, inject using a 90 degree angle; if the depth is 1 inch, inject using a 45 degree angle.

Subcutaneous Compared to Intramuscular Injection:

Subcutaneous Injection
Intramuscular Injection

Subcutaneous Tissue:

Equipment for Subcutaneous Injections:

Tuberculin Syringe  
Insulin Syringe  

NOTE: These syringes are NOT interchangeable