Objective
To investigate the relationship between the curvature of the cervical spine and various clinical parameters and to identify the validity of new curvature measurement methods.

Method
The cervical spine curvature was assessed on lateral view of plain radiographs by three measurement indices. Index 1 is the ratio of length of line drawn by C2-C7 posteroinferior points and the longest length of vertical line to the posterior curve of C2-C7. Index 2 is the angle formed by three points of index 1. Index 3 is the sum of each distance from line drawn by C2-C7 posteroinferior point to C3-C7 posterior mid-points. The difference of each group and the relationship between pain scale and three indices were statistically analyzed by t-test and Pearson's correlation test.

Results
Sixty-three percent of control group patients showed a straight or kyphotic curvature and younger women group was more likely to have a straight curvature than other age groups. The newly designed measurement methods reflect the diagnostic significance of cervical curvature type measurement. Cervical lordosis did not exactly correlate with pain scale, symptom duration and the difference of clinical diagnosis. But the patients showing interval changes of pain scale were revealed the correlative change of curvature indices with each correlation coefficient of ⁣0.43, ⁣0.69 and ⁣0.55 respectively.

Conclusion
The altered cervical curvature is less valuable for the diagnostic significance and did not relate to the pain scale and duration, but cervical curvature reflect the interval change of the pain scale.