Sent to attorneys August 18, 2026.
A short note on medial branch blocks (MBBs), the diagnostic injection used to prove that a facet joint at the back of the spine is generating a patient’s pain. The facet joints are the paired joints on either side of each vertebral level. Each one is supplied by tiny nerve twigs called medial branches, which come off the dorsal ramus of the spinal nerve — the branch that turns backward as soon as the nerve exits the spine. Because every facet joint has a dual nerve supply from the medial branch of its own level and the medial branch of the level above, at least two branches must be blocked to test a single joint. A well-performed MBB that gives strong short-term relief is what qualifies a patient for radiofrequency ablation as the follow-on treatment.
The levels that carry the load. In the neck, C5-6 and C6-7 are the most common axial pain generators after whiplash-type injuries; C2-3 is the classic source of headache of cervical origin. In the low back, L4-5 and L5-S1 do most of the work, particularly after hyperextension or axial-loading injuries. Thoracic facet pain exists but is uncommon in litigation. When a records reviewer sees medial branch blocks documented at these levels, that is not shotgun treatment — that is the anatomically sensible workup.
The headache piece. The C2-3 facet is innervated by the third occipital nerve, a specialized branch of the C3 dorsal ramus, and it is a well-recognized source of occipital and upper-neck headaches after a neck injury. C3-4 can also contribute; C1-2 headaches come from a different mechanism and are worked up differently. When a patient reports post-collision headaches that start at the base of the skull and spread over the crown, a third occipital nerve/C2-3 diagnostic block is the correct anatomic path — not a generic migraine workup.
I hope you found this interesting.
Questions or comments about today’s educational update, or a topic you would like us to address in a future edition? Contact us through our website: OrthOpinions
F. Allen Johnston, MD
Louisiana Orthopedic Institute
Baton Rouge
(225) 751-6666 Office
(225) 270-0000 Cell
See also the hub article: Facet joint pain: diagnosis, conservative care, medial branch blocks, and radiofrequency ablation.
