A neck injury a scanner cannot see, in a nervous system nobody examined

WHIPLASH: THE JOINT AND THE SYSTEM AROUND IT

Neck pain that lasts months after whiplash, with a normal MRI, most often comes from a cervical facet joint (a small joint at the back of the neck). It is the most common identified source in controlled block studies. The other part of the problem is a nervous system that has changed how it processes signals from that joint.

You were stopped. Somebody was not. Months later the neck still hurts. The MRI report says “no acute abnormality,” and the hint in the room is that there is nothing there. There are two things there. One is a joint the size of a thumbnail. The other is a nervous system that has changed how it processes signals from it.

Two environments, and treating only one is how this fails

A neck injury that still hurts at six months is almost never a single-variable problem. There is a structure sending a signal, and there is a system deciding what that signal means. Treat the structure in a sensitized (overreactive) system, and you get a patient with four procedures and no lasting result. Treat the system but ignore a truly painful joint, and you get someone told to manage their stress. Yet the injury is real.

We work both, and we say which one we are working on. That is the whole of our position on the neck. The sections below are what it is built from.

What a rear-end impact does to the back of the neck

In the first fraction of a second after impact, the cervical spine (neck) bends into a brief S-shape. The lower segments extend while the upper segments are still flexed. The facet joints — the paired joints at the back of each level that guide and limit motion — are squeezed at their back edge. Their capsules are stretched past their normal range. The capsule is packed with nerves. That is the injury. It is a soft-tissue injury inside a joint, which is exactly the kind of injury a still image is worst at showing.

The number that settled this thirty years ago

This is not a theory that needs defending. It was tested with controlled diagnostic blocks, twice, and published in Spine.

• The first study took 50 consecutive patients (patients in a row) with chronic neck pain after whiplash. Double-blind comparative blocks found a painful cervical facet joint in 54% (95% CI 40% to 68%).
• The next study took 68 consecutive referred patients and used placebo-controlled blocks. Each patient got two different local anesthetics and a saline injection. They came in random order, and the tests were double-blind. The overall prevalence was 60% (95% CI 46% to 73%).

The second study exists because the obvious objection to the first was placebo response. The joints survived the challenge. In a patient with chronic neck pain after whiplash, the cervical facet joints are the single most common identified source, and it is not close.

Why the MRI is unremarkable, and why that cuts both ways

A capsular injury with no fracture, no disc extrusion and no cord compression gives a normal report. That is true on the scan a hospital orders after a collision. That scan was ordered to rule out catastrophe, and it did its job.

The reverse error is just as common. Where an image does show something, degenerative findings get read as the explanation. A systematic review of 3,110 asymptomatic people (people with no symptoms) across 33 studies found disc degeneration in 37% of 20-year-olds, rising to 96% of 80-year-olds. Disc bulges showed up in 30% to 84% across the same span, in people with no pain at all. A finding that common cannot explain one person's pain by itself, and it cannot date it.

What identifies the joint instead: the block

The cervical facet joints are diagnosed by how they respond when the small medial branch nerves that supply them are numbed. The finding is relief that is complete, repeatable and timed to the anesthetic used. That is a diagnostic procedure, not a treatment. Its purpose is to decide whether the next thing done to your neck is aimed at the right structure.

We do not inject a cervical level a block has not confirmed. We apply the same rule in the low back on the facet page and the sacroiliac page. It is why the procedure that follows is not a coin flip.

Where the graded evidence sits, and where it does not

Be careful what gets carried over here. The 2025 ASIPP guideline grades regenerative therapies for the lumbar spine (low back), target by target. Intradiscal (into the disc) platelet-rich plasma and bone marrow concentrate get Level III, Fair. Epidural platelet-rich plasma gets Level III, Fair. Facet gets Level IV, Limited. Sacroiliac gets Level IV, Limited. Those grades belong to the lumbar spine and do not automatically carry to the neck.

The multispecialty chronic pain guidelines rated regenerative treatment for tendon, muscle, joint, disc and nerve targets. They used United States Preventive Services Task Force criteria. The neck evidence is far thinner than the knee evidence. So our neck practice is led by diagnosis. Confirm the level, and treat the confirmed level. Use the modality the evidence supports for that target, not the one the patient arrived asking for.

The system half, and the data behind taking it seriously

A prospective cohort followed 65 of an initial 76 acutely injured people out to two and three years. Four things measured early stayed significant predictors of a poor long-term outcome. Two were higher early disability scores and older age. The third was cold hyperalgesia — a pain response to cold that is not normal. That is a nervous-system finding, not a neck finding. The fourth was post-traumatic stress symptoms.

Two of those four are not orthopedic at all, and neither can be changed with a needle. Sleep, inflammatory load and autonomic state (the body’s automatic nervous system controls) are the setting a neck joint is asked to recover inside. We assess them for the same reason we assess them everywhere else on this site, described on the metabolic health page. The structure gets the catalyst. The system gets the rest of the plan.

What people ask after a neck injury

My MRI was normal. Does that mean nothing is wrong?

No. It means nothing catastrophic is wrong, which is what that scan was ordered to find out. The most common identified source of chronic (long-term) neck pain after whiplash is a facet joint capsule. That injury does not show on a standard cervical (neck) MRI — the wider version of the problem is on the page about normal scans.

How do you know which joint is causing it?

By numbing the medial branch nerves that supply a specific level. Then we watch whether the pain goes completely, repeatably, and for as long as the anesthetic predicts. It is the same discipline used in the low back, described on the facet joint page.

Can PRP be injected into my neck?

Only into a target a block has confirmed. And we tell you clearly what the evidence for that target is. That is because the graded guideline record here is mostly lumbar (low back), not cervical (neck). Where we stand on treating an unconfirmed level is on the spine and sacroiliac page.

It has been two years. Is it too late?

It is not too late to identify the source. Identifying it is usually what has never been done — chronic post-whiplash pain is the exact group those block studies recruited. What a long gap changes is the realistic target, discussed on the tissue timeline page.

Why are you asking about my sleep and my stress after a car accident?

Because of the cohort followed out to three years. In it, cold hyperalgesia and post-traumatic stress symptoms predicted a poor outcome as strongly as the early disability score did. The joint is one setting and the nervous system is another. We treat both — what gets measured is on the metabolic health page.

Where to go from here

• Terrain first, then the catalyst
• Facet pain and the diagnostic block
• When a fused neck still hurts
• Shoulder pain that is coming from the neck
• When the scan is normal and the injury is not
• Why we ask for bloodwork