When you look at the neck from the side view, there should be a curve. This study showed that the curve should be about 31-40 degrees, and if you have less than 20 degrees of curve, you are more likely to have neck related symptoms.
J Manipulative Physiol Ther. 2005 Mar-Apr;28(3):187-93.
Determining the relationship between cervical lordosis and neck complaints
McAviney J, Schulz D, Bock R, Harrison DE, Holland B.
Abstract
OBJECTIVE:
To investigate the presence of a “functionally normal” cervical lordosis and identify if this and the amount of forward head posture are related to neck complaints.
METHODS:
Using the posterior tangent method, an angle of cervical lordosis was measured from C2 through C7 vertebrae on 277 lateral cervical x-rays. Anterior weight bearing was measured as the horizontal distance of the posterior superior body of the C2 vertebra compared to a vertical line drawn superiorly from the posterior inferior body of the C7 vertebra. The measurements were sorted into 2 groups, cervicalcomplaint and noncervical complaint groups. The data were then partitioned into age by decades, sex, and angle categories.
RESULTS:
Patients with lordosis of 20 degrees or less were more likely to have cervicogenic symptoms (P < .001). The association between cervical pain and lordosis of 0 degrees or less was significant (P < .0001). The odds that a patient with cervical pain had a lordosis of 0 degrees or less was 18 times greater than for a patient with a noncervical complaint. Patients with cervical pain had less lordosis and this was consistent over all age ranges. Males had larger median cervical lordosis than females (20 degrees vs 14 degrees) (2-sided Mann-Whitney U test, P = .016). When partitioned by age grouping, this trend is significant only in the 40- to 49-year-old range (2-sided Mann-Whitney U test, P < .01).
CONCLUSION:
We found a statistically significant association between cervical pain and lordosis < 20 degrees and a “clinically normal” range for cervical lordosis of 31 degrees to 40 degrees. Maintenance of a lordosis in the range of 31 degrees to 40 degrees could be a clinical goal for chiropractic treatment.