Background
Cervical kyphosis is frequently observed in the patients without axial neck pain and sigmoid curvatures are parts of the variety of cervical kyphosis. Purpose: This study was designed to investigate the characteristics of the static and dynamic alignment of the cervical spine with sigmoid configurations.
Methods
Figty patients without changes of the cervical curvatures after subsidence of axial neck pain were enrolled in this study. Based on the alignment of cervical spine on lateral radiographs, cervical alignments were classified: kyphotic (K), kypho-lordotic (KL), lordo-kyphotic (LK), and Lordotic (L) group. The sagittal alignment angles and each segmental angle were measured using the Harrison method on neutral, flexion, and extension-lateral radiographs.
Results
The mean ratio of segmental ROM to C2-7 ROM revealed a similar pattern across the cervical levels without statistical difference between the groups. In the KL and LK group, the linear graphs for the mean ratio of segmental angles to C2-7 angles in flexion and extension showed a mirror image with respect to the C4-5 level. The lordotic components of both curves demonstrated larger ratio of segmental angles in flexion than the kyphotic components. The kyphotic components of both curves demonstrated larger ratio of segmental angles in extension than the lordotic components.
Conclusions
The lordotic and kyphotic components regardless of the type of sigmoid curvatures seem to adhere to constant dynamic behavior during flexion and extension. Therefore, the KL and LK cervical alignments may have the opposite dynamic behaviors in the high and low cervical levels.

Purpose
To compare the difference of cervical alignment between cervical lateral radiograph and whole-spine lateral radiograph by the effects of radiographic position and to assess the effect of the shoulder flexed position to cervical lordotic curvature and head position.
Materials and Methods
We retrospectively evaluated 43 asymptomatic adult patients who were taken horizontal gazing standing cervical and whole-spine lateral radiograph simultaneously from Sep. 2008 to Dec. 2009. Cervical lateral radiograph was taken with the arms extended and hand gently clasped on both side and whole-spine lateral radiograph was taken in the position that subject were relaxed standing with fists-on-clavicles position. Cervical sagittal alignment were analyzed the following parameters. (1) Gore angle (GA, C2-7 angle); (2) Cobb angle (CA, C2-7 angle); (3) translation distance (TD, distance of C2 compared with vertical line through the posterior-inferior body of C7); (4) McGregor angle (MA, angle between McGregor line and horizontal line).
Results
The mean of GA and CA in cervical radiograph were -12.64° and -9.96°, whereas -7.12° and -4.98° in wholespine radiograph. The mean TD and MA were in cervical radiograph were 16.95mm and 7.15°, whereas, 14.97mm and 6.54° respectively in whole-spine radiograph.
Conclusion
Our study showed the significant differences of cervical alignment and head position between standing cervical lateral and whole-spine lateral radiograph. The radiographic posture of whole-spine lateral radiograph with horizontal gazing and fists-on-clavicles position make cervical alignment and head position less lordotic and posterior translation compared to cervical radiograph.