Cervical PIV (Posterior Intervertebral) Joint Dysfunction

The naming, first, because it costs marks and wastes search time. UniSA teaches this joint as the PIV joint — the posterior intervertebral joint. The literature calls the same structure the cervical facet joint or the cervical zygapophysial joint (also spelled zygapophyseal). PubMed holds zero records using the string "PIV joint". You type one name and the literature prints the other. Write PIV joint in your notes; search cervical zygapophysial, cervical zygapophyseal, cervical facet and medial branch block when you go looking. Same joint every time.

Who: Anyone with a neck. Often after a sudden rotation, a lateral flexion, an awkward night's sleep — or a rear-end collision, which is where most of the evidence was built.
What: Unilateral, non-midline neck pain ± referral into the scapular region, stopping at the shoulder.
How it behaves: Aggs: extension, rotation, sustained postures, the movement that started it. Eases: unloading, gentle movement, changing position. Sharp or catching early → dull ache later.

The illness script in one line:

One segment's posterior joint made sore and stiff — so the pain sits off the midline on one side, refers to the scapula, never goes below the shoulder, and comes back under your thumb at a single level.

The one thing to take from this page:

The reference standard for this diagnosis is a controlled medial branch block — two anaesthetics of different duration, or an anaesthetic against placebo saline, under fluoroscopy. Nobody on a five-week placement will perform one, order one or see the result of one. Every number below is measured against a test you cannot reach. That is the honest frame for the whole page.

(GBD 2021 [1] [2] [3] [4] [5] [6] [7] [8] [9].)

No Australian guideline exists for this presentation. ACSQHC publishes twenty-one clinical care standards and the only musculoskeletal ones are Low Back Pain (2022) and Osteoarthritis of the Knee (2024). No cervical standard. No RACGP neck guideline. Anchored to Neck Pain: Revision 2017 [10], named as the profession anchor and nothing more.

Now the other half, and it is this page's contribution. The absence of an Australian guideline is not an absence of Australian evidence. The reference standard for this entire pattern was built in Australia — Bogduk, Lord, Barnsley and Wallis at the Cervical Spine Research Unit in Newcastle; Jull at UQ, published in the MJA; Speldewinde's clinical audit, also MJA; the current serious-adverse-event review from UQ. We wrote the evidence and never wrote the guideline.

The only guideline-shaped document that names this pattern is interventional pain medicine — controlled blocks, image guidance, radiofrequency ablation after confirmation [11]. Not one line of it is physiotherapy.

Patterns > Labels. "C5-6 facet joint" names a structure you cannot confirm. Unilateral, non-midline, one level, comparable sign, nothing below the shoulder names the problem you can treat on Monday. Check it with your educator.

Five stages, in order. And the honest opening, because it is a finding rather than a failure: the subjective does less work on this page than on any other neck pattern. In 100 consecutive chronic post-whiplash patients taken to controlled third occipital nerve blocks, there were "no distinguishing features on history or examination that enabled a definitive diagnosis to be made before the nerve blocks" — the single significant clinical association was tenderness over C2-3, p=0.01 [7].

So the subjective here does what a subjective is actually for. It generates a level hypothesis, sets your dosage, and rules out the neighbours. It does not name the joint.

MAIN PROBLEM

"It's this one spot, right side, just here. Woke up with it Tuesday and I can't turn my head to reverse the car. It goes into my shoulder blade a bit. Nothing down the arm."

Listen for one spot, one side, and nothing down the arm. Ask them to point with one finger. If they use a whole hand across the back of the neck, you are on the mechanical neck pain page instead.

BODY CHART

• P1: unilateral, non-midline, over the posterolateral neck at one or two levels. P2 commonly into the scapular region or the upper trapezius. Mark the shoulder as the boundary — this pattern does not go below it.
• Draw P+ / P++ where they show you the worst of it, and mark the side clearly. Check and mark both sides. Bilateral is a different conversation.
• The pain charts you were shown come from five people. Distending each joint capsule in 5 asymptomatic volunteers produced a clinically distinguishable pattern at every segment, and every segmental chart in every textbook descends from that study [12].
• The correction, from real patients: in patients with block-proven joints, pain location and distribution "varies considerably; more so than in studies of normal volunteers". Adjacent segments overlap; remote segments do not [13]. No accuracy figure exists in that paper — do not quote one from it.
• So use the chart to generate a level, never to name one. It is better at that than you expect: two observers predicted the correct segmental level from the body diagram in all 9 patients later shown to have a symptomatic joint — in a study of ten people [14]. And in the Australian audit, the level was found from a standard pain diagram at the first attempt in 83% (29/35) [5].
• If headache is on the chart, mark whether it is suboccipital → frontal/temporal and unilateral. That is the C2-3 / third occipital nerve branch: prevalence 27% (95% CI 18–36) of all chronic post-whiplash neck pain, 53% (37–68) where headache dominated (Lord et al. 1994).

BEHAVIOUR

• Aggs: extension, rotation to the painful side, sustained postures, the position they slept in, reversing the car, the desk after lunch.
  Eases: unloading, supporting the head, gentle movement, changing position. Sharp or catching early → dull ache as it settles.
• 24-hr pattern: the position they slept in and the desk after lunch are in the Aggs; gentle movement and changing position ease it. Morning stiffness under 30 minutes = M.
• Night: the position they slept in is in the Aggs. Night pain alongside progressive constant pain or new neurological signs is the medical-review row in §6.
• Severity: VAS 0–10 at best / at worst / right now.
• Coding: usually In — intermittent, position-driven — moving to P when irritable, and back to Is as it settles. Morning stiffness <30 min = M; >30 min = In, and >30 min in a young patient with bilateral symptoms should make you re-ask the inflammatory questions.
• Irritability decides your dosage, and it has three parts. Resting symptoms? How vigorous is the activity that provokes it? How long does it take to settle? High irritability = Grades I–II to P1 only, no overpressure (o.p.), and no combined-movement or quadrant provocation on day one. You are choosing a technique from this answer, not from a diagnosis.

HISTORY

• Onset: sudden rotation or lateral flexion, an awkward sleeping position, a reaching-and-turning movement — or a rear-end collision. Date it, and date what it has done since.
• Read the prevalence literature knowing where it came from. The high numbers are post-whiplash, referred, tertiary populations: 54% (40–68) with comparative blocks [3] and 60% (46–73) with placebo-controlled blocks [4]. The lower ones are mixed and clinical: 39% (32–45) in a general chronic spinal pain practice [6] and 36% (27–45) in the Australian audit, where a confirmatory repeat block was required and many patients declined (Speldewinde et al. 2001). The published range across 12 controlled studies is 36% to 67% [2].
  Two of the four foundational prevalence studies are exclusively whiplash cohorts, and they produce the two highest figures. Most of what the profession "knows" about this joint was learned in a post-traumatic cohort at Newcastle. Do not quote 60% at a desk worker with a stiff neck. If there is a collision in the history, see the whiplash page as well as this one.
• Previous episodes, previous imaging, what they have been told, and what helped last time.
• Anything about a worst-ever, new or unfamiliar head or neck pain goes straight to section 4 before you go any further.

SPECIAL / SCREENING QUESTIONS

Every patient. Every time. Before you touch them — and on this page that sentence is not a formality, because manual therapy is the treatment.

• CAD/VBI: the 5 D's and 3 N's — dizziness, diplopia, dysarthria, dysphagia, drop attacks; nausea, numbness, nystagmus. Plus new, unfamiliar or severe head/neck pain, and any recent trauma. Cervical arterial dysfunction.
• Myelopathy: both hands? Dropping things, buttons, handwriting? Unsteady on your feet? Bladder change? Cervical myelopathy.
• Fracture: after trauma, run the Canadian C-spine Rule before anything else.
• The ordinary serious ones: severe pain becoming progressive and constant, night pain, new neurological signs, unexplained weight loss, fever, cancer history.
• Arm symptoms below the shoulder — dermatomal band, paraesthesia, numbness, myotomal weakness — moves you to cervical radiculopathy. This pattern does not go below the shoulder.

Rank the mechanical patterns — then rule out the dangerous ones first, in section 4. One discriminating feature each. That is all you need to move between them.

And if headache dominates, branch before you rank. Unilateral suboccipital → frontal/temporal headache triggered by neck movement is the C2-3 / third occipital nerve presentation. The cervical flexion-rotation test separates cervicogenic headache with sensitivity 83.0% (95% CI 70.0–92.0), specificity 83.0% (71.0–91.0), +LR 5.0 (2.6–9.5), −LR 0.2 (0.1–0.4) at moderate certainty — 4 studies, n=182, and the single most credible cervical test anywhere on this page [16].

The check that stops you over-calling it: a lower cervical PIV joint does not close the FRT. Mean rotation to the limited side was 37.5° in lower cervical facet pain versus 26° in cervicogenic headache (P<0.01), with a positive cut-off of 32° — sensitivity 75%, specificity 92%, in 24 patients, one examiner [17].

Rank the mechanical ones. Rule out the dangerous ones first. Section 4 is not optional reading on this page — it is the section that decides whether you are allowed to treat.