Cervical Lordosis: Loss, Reversal, and X-Ray Measurement
A step-by-step guide to measuring cervical lordosis by hand on a lateral X-ray, with commonly cited reference ranges and sources.
For educational use. Not a diagnostic device. Clinical decisions remain with the licensed provider.
How to Measure Cervical Lordosis
Cervical lordosis is the normal backward curve of the neck on a lateral X-ray. Two radiographic methods are commonly used to put a number on that curve, and they are not interchangeable.
Cobb C2-C7 method. Draw a line along the inferior endplate of C2 and another along the inferior endplate of C7, then measure the angle between them, the same technique used for scoliosis, applied to the sagittal plane.
Harrison posterior tangent method. Draw a line tangent to the posterior margin of the C2 vertebral body and another tangent to the posterior margin of the C7 vertebral body, then measure the angle between them.
The two methods generally produce different numbers for the same X-ray. A 2018 meta-analysis of asymptomatic adults reported an average of roughly 12.7° with the Cobb C2-C7 method versus roughly 18.6° with the Harrison posterior tangent method, and a separate study measuring the same films both ways found an even larger gap, about 26.8° (Cobb) versus 34.5° (Harrison posterior tangent). Always note which method produced a given number before comparing it to a reference range or an earlier film.
As with any manual angle measurement, where exactly you place each point on the vertebral margin affects the result, so treat a single measurement as an estimate rather than an exact value, and prefer comparing films measured the same way over time.
What Does Loss of Cervical Lordosis Mean?
A curve that measures lower than typical reference values for its method is often described as loss of cervical lordosis, or straightening. It is a measurement finding, not a diagnosis on its own, and is read alongside the patient's history, symptoms, and the rest of the radiographic picture.
What Is Reverse Cervical Lordosis?
A curve that bows the opposite direction entirely, rather than just flattening, is described as reverse cervical lordosis, or cervical kyphosis. As with loss of lordosis, this is a radiographic finding that is interpreted in clinical context, not a stand-alone diagnosis.
What Is George’s Line?
George’s line is the posterior vertebral body line on a lateral cervical X-ray, one of the alignment lines used alongside curvature measurements to check for malalignment. It should form a smooth, continuous curve without step-offs between vertebrae; a step in the line can point to segmental translation independent of the overall lordosis angle. George’s Line is also one of the tools in the ChiroPax Measurement Tools catalog.
Commonly Cited Reference Ranges
| Method | Commonly cited mean (asymptomatic adults) |
|---|---|
| Cobb C2-C7 | ~12.7° (95% CI 6.6°-18.8°); other reviews report means up to ~18.7°, with ranges cited as wide as 10°-35° |
| Harrison posterior tangent | ~18.6° (95% CI 14.5°-22.6°); individual studies report means as high as ~34.5° |
Ranges vary by study, age, and sex, and by the exact method used. These figures describe group averages in research studies, not a per-patient normal/abnormal cutoff.
How ChiroPax Supports Cervical Measurements
ChiroPax automates cervical curvature measurement as part of its AI spinal analysis, covered on the Chiropractic X-Ray Analysis Software page, with results overlaid directly on the X-ray instead of requiring manual endplate or tangent marking.
Sources
- “Cervical lordosis in asymptomatic individuals: a meta-analysis,” Journal of Orthopaedic Surgery and Research, 2018 - Cobb C2-C7 vs. Harrison posterior tangent comparison.
- Radiopaedia, “Cervical spine alignment” - posterior vertebral body line (George’s line) and normal sagittal alignment.
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