How do doctors know where in the spine to put an injection if they are going to inject something to relieve back pain?

When doctors study the different parts of the body, they learn the area in depth. For example, with the spine, they learn how to feel for the spine, what surrounds the spine, what makes up the structures of the spine, how wide or thick the body parts are, and so on.

A doctor who is qualified and comfortable to give injections in the spine would likely order x-rays to see if there isn't anything unusual about your spine. Then, he or she is able to feel your spine to see where the injections would go. Through learning and experience, the doctor knows where to inject, how deep to inject, what to feel for as the needle gets to certain areas, and what to watch for.

It's not an easy procedure and it takes a good deal of skill, but the training that the doctors receive provide them with that skill.