Injection Sites Quick Revision for Nursing Students Understanding the correct injection site is essential for safe medication administration. Intramuscular (IM) Injection Sites Deltoid Vastus Lateralis Ventrogluteal B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics 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 B12 vitamin Store How to inject B12 in your arm How to Give B12 Injections at Home to Yourself PA Relief