Objectives : This study was designed to evaluate various tools including C-spine X-ray for estimating cervical curvature and identify the effect of wooden pillow on patients diagnosed with straightening of cervical curvature. Methods : This study was carried out on 51 subjects who were encountered traffic accident suffering cervical pain and diagnosed with straightening of cervical curvature by X-ray. 51 subjects were divided into wooden pillow(experimental) group and conservative therapy(control) group. Visual analogue scale, neck disability index and lateral pictures were used and compared after treatment. C-spine AP., Lat. X-ray were used on admission day to calculate cervical curvature and scoliosis by various ways. Results : 4 different measurements of cervical curvature didn`t show common results. Both wooden pillow(experimental) group and conservative therapy(control) group showed significant improvement in the visual analogue scale(VAS) and neck disability index(NDI) after hospital treatment. Comparison between center line pictured by lateral view and C-spine Lat. pictured by X-ray showed significant difference in cervical curvature. Lateral deviation of cervical vertebra showed lengthened distance between mastoid process and spinous process of C7. Conclusion : As a result of this research, I found out that various tools for calculating cervical lordosis could derive different results and C-spine AP., Lat X-ray could cause artificial cervical lordosis. According to visual analogue scale(VAS) and neck disability index(NDI) wooden pillow was not effective to reduce pain & disability caused by straightening of cervical curvature. Futhermore, correction effect of straightening of cervical curvature and scoliosis by wooden pillow was weak.