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 Best Vitamin B12 Injection Sites? ThinWorks Vitamin B12 & C Injections Places for Intramuscular Injection: 4 Safe Spots Best Vitamin B12 Injection Sites: Where to Inject B12 PA Relief Subcutaneous (SC) and Intramuscular (IM) Injections Must Knows for Subcutaneous administration: Pinch skin with non dominant hand and hold syringe with dominant hand Always inject: 2 inches away from umbilicus (for abdomen) 3 inches