Locating the 18 Classic Tender Points
Nine bilateral landmarks are palpated across the body.
- 18: Total points (9 bilateral pairs)
- 1990: Criteria year (ACR classification)
- ≥3 mo: Pain duration req. (widespread pain)
- 4: Body regions (quadrants + axial)
Landmark set
Occiput, low cervical, trapezius, supraspinatus, second rib, lateral epicondyle, gluteal, greater trochanter, knee.
Exam setup
Patient relaxed, examiner uses consistent digital or algometer pressure.
Applying Calibrated Pressure with a Dolorimeter
A handheld algometer measures the pain-onset threshold in kg/cm².
- ~4.0: Normal threshold (kg/cm² before pain)
- <4.0: FM threshold (kg/cm² typical)
- 1 cm²: Probe tip area (rubber-tipped)
- ~1 kg/s: Rate of pressure (steady increase)
Reading the gauge
Pressure rises until patient reports first pain sensation.
Standardization
Consistent rate and tip size reduce examiner variability.
Testing Each of the 18 Points in Order
Points are scored one at a time as tender or non-tender.
- Binary: Scoring (tender / non-tender)
- L → R: Order (per landmark)
- ~5 s: Time per point (approx. exam pace)
- ~3 min: Full exam time (all 18 points)
Progressive scrubber
Slider reveals each site's status as testing proceeds.
Blinding
Patient does not see which site is being pressed.
Counting Tender Points Against the ≥11/18 Rule
A running total is compared against the historical cutoff.
- ≥11/18: Diagnostic cutoff (tender points)
- ≥3 mo: Plus pain criterion (widespread pain)
- ~88%: Sensitivity (reported historically)
- ~81%: Specificity (reported historically)
Running count
Tender count updates live as points are tested.
Interpretation
Count alone does not confirm diagnosis without pain history.
Historical Threshold vs. the 2016 WPI/SSS Criteria
Tender-point exam has been largely superseded since 2016.
- Exam-based: 1990 criteria (18-point palpation)
- WPI + SSS: 2016 criteria (no physical exam req.)
- 0–19: WPI scale (widespread pain index)
- 0–12: SSS scale (symptom severity score)
Why the shift
Tender points varied with examiner pressure and patient mood.
Current use
Tender points still used clinically as a supportive sign.