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

WHIPLASH: THE JOINT AND THE SYSTEM AROUND IT

You were stopped. Somebody was not. Months later the neck still hurts, the MRI report says “no acute abnormality,” and the implication hanging 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 cervical injury that is still hurting at six months is almost never a single-variable problem. There is a structure generating a signal, and there is a system deciding what that signal means. Treat the structure in a sensitized system and you get the patient who has had four procedures and no durable result. Treat the system while ignoring a genuinely painful joint and you get someone told to manage their stress about an injury that is real.

We work both, and we say which one we are working on. That is the whole of our position on the neck, and 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 deforms into a transient 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 compressed at their posterior margin and their capsules are stretched beyond their normal range. The capsule is densely innervated. That is the injury, and it is a soft-tissue injury inside a joint, which is precisely the category a static image is worst at.

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.

• In 50 consecutive patients with chronic neck pain after whiplash, double-blind comparative blocks identified a painful cervical facet joint in 54% (95% CI 40% to 68%).
• In 68 consecutive referred patients, using placebo-controlled blocks — two different local anesthetics and a saline injection, in random order, under double-blind conditions — 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 produces a normal report on the protocol a hospital orders after a collision. That study 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 — and a systematic review of 3,110 asymptomatic people across 33 studies found disc degeneration in 37% of 20-year-olds rising to 96% of 80-year-olds, with disc bulges 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 their response to anesthetizing the small medial branch nerves that supply them. Relief that is complete, reproducible and time-locked to the anesthetic used is the finding. That is a diagnostic procedure, not a treatment, and 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. The same rule is applied in the low back on the facet page and the sacroiliac page, and 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 transferred here. The 2025 ASIPP guideline grades regenerative therapies for the lumbar spine, target by target — intradiscal platelet-rich plasma and bone marrow concentrate at Level III, Fair; epidural platelet-rich plasma at Level III, Fair; facet at Level IV, Limited; sacroiliac at Level IV, Limited. Those grades belong to the lumbar spine and do not automatically carry to the neck.

The multispecialty chronic pain guidelines appraised regenerative treatment across tendon, muscle, joint, disc and nerve targets against United States Preventive Services Task Force criteria, and the cervical evidence is thinner than the knee evidence by a wide margin. So our cervical practice is diagnosis-led: confirm the level, treat the confirmed level, and use the modality the evidence supports for that target rather than 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 remained significant predictors of a poor long-term outcome: higher initial disability scores, older age, cold hyperalgesia — an abnormal pain response to cold, which is a nervous-system finding rather than a neck finding — and post-traumatic stress symptoms.

Two of those four are not orthopedic at all, and neither is modifiable with a needle. Sleep, inflammatory load and autonomic state are the environment that a cervical joint is being asked to recover inside, and 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 study was ordered to determine. The most common identified source of chronic post-whiplash neck pain is a facet joint capsule, and that injury does not appear on a standard cervical MRI — the wider version of the problem is on the page about normal scans.

How do you know which joint is causing it?

By anesthetizing the medial branch nerves supplying a specific level and observing whether the pain goes completely, reproducibly, and for the duration the anesthetic predicts. It is the same discipline applied 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 with a clear statement of what the evidence for that specific target is, because the graded guideline record here is largely lumbar rather than cervical. 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, and identifying it is usually what has never been done — chronic post-whiplash pain is the exact population 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 in the cohort followed out to three years, cold hyperalgesia and post-traumatic stress symptoms predicted a poor outcome as strongly as the initial disability score did. The joint is one environment and the nervous system is another, and 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