What are the medial branch nerves and why are medial branch blocks helpful? Medial branch nerves are the very small nerves that allow one to feel pain from the facet joints. These nerves do not control any muscles or sensation in your arms or legs. They are located along a bony groove in your low back, neck and over a bone in your mid-back. We have strong evidence to suspect that your facet joints are the source of your pain*. Unfortunately, simple joint injections and/or other treatments have not provided you with adequate pain relief. Therefore, you may benefit from having the small medial branch nerves and their pain signals interrupted via a controlled non-surgical heat lesion produced by a special needle. This more permanent treatment is called RF medial branch neurotomy.