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Reliability of Two Methods Used to Assess A/O Joint Congruence, Symmetry and Exactness of Fit

Lafayette Briggs, DC, MT (ASCP) 

Journal of Vertebral Subluxation Research ~ May 26, 2008 ~ Pages 1-4



Objective: To assess the reliability of the analysis stage of two quantitative methods used in a previous study that examined the atlanto-occipital (A/O) joint surface areas to determine congruence and exactness of fit.


Methods: Six cadavers (twelve A/O) joints were exposed and analyzed. Method 1 involves photo-analysis and Method 2 is a point-counting technique. The reliability of both methods is determined by examining three trials of repeated measurements (10 measurements per trial) taken from the four articular surfaces of the A/O joint. Pearson’s product moment correlation coefficients and significant agreement (p< 0.05) are used to estimate the repeatability of the methods. In addition coefficients of variation (CVs) are calculated, which allows variation from the means to be compared as a percent.


Results: Study results show that correlations were significant for all three trials in both methods—except trial 1 vs 2 and 1 vs 3, for Method 1 subject #999. Comparison of the two methods show moderate to high correlations with no significant difference between the two methods and coefficient of variation (CV) differences between the two methods of less than 10 percent for all subjects analyzed.


Conclusion: There is no significant difference between the two methods. Method 1 and Method 2 are repeatable over three trials of 120 measurements. There is close agreement between the coefficients of variation (CVs) for all six cadavers when the two methods are compared.


Key Words: Chiropractic, Atlas, Condyle, Symmetry, Misalignment, Atlanto-occipital subluxation

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