Intramuscular and Subcutaneous Injections

During my week of thanksgiving vacation I volunteered at the pediatric clinic that I do my mentorship at. I talked with my mentor, Dr. Chen. She was explaining to me the different types of ways you have to inject a vaccine to a patient. If you are giving a subcutaneous injection, you will inject directly into the fatty tissue; meaning under the skin and overlying the muscle.  If you are giving an intramuscular injection, you will inject directly into the deltoid muscle; meaning below the shoulder on the upper arm. I found these two type of ways very interesting because I knew of no such thing.