B12 Injections at Home Safety Guide for Self Administration Infusion For Health Common IM Injection Sites Deltoid (Upper Arm) Location: About 23 finger widths below the acromion process (shoulder bone). Best for: Vaccines and small volume injections (1 mL). Notes: Easy to access but limited Vastus Lateralis Intramuscular Injection Everything You Need To Know Dr. Nabil Ebraheim How to Give a B12 Injection: Step By Step Instructions Intramuscular injection is shown at 90 because the goal is to reach the muscle, the deepest layer in this comparison. That route is chosen when medication needs reliable absorption through the muscle's Where Does B12 Injection Go TikTok