Background: Forward head posture (FHP) and altered cervical lordotic curvatures are common spine displacements often associated with neck pain and disability. Two primary categories for determining FHP exist: radiographic and postural measurements. Methods: This study investigated the correlation between the craniovertebral angle (CVA), the radiographically measured C2-C7 sagittal vertical axis (SVA), and cervical lordosis (absolute rotation angle: ARA C2-C7) in a sample of participants with chronic myofascial pain (CMP). In 120 participants, we performed both a postural measurement of the CVA and a lateral cervical radiograph, where the C2-C7 SVA and ARA C2-C7 were measured. A linear-regression R2 value to assess the correlation between the CVA, C2-C7 SVA, and ARA C2-C7 was sought. Results: A statistically significant weak linear fit was identified (Spearman's r = 0.549; R2 = 0.30, p < 0.001) between the CVA and C2-C7 SVA, having considerable variation between the two measures. A statistically significant linear fit (very weak) was identified for the lordosis ARA C2-C7 and the CVA: Spearman's r = 0.524; R2 = 0.275; p < 0.001. A value of 50° for the CVA corresponded to a value of 20 mm for the C2-C7 SVA on an X-ray. Conclusion: While the CVA and radiographic C2-C7 SVA are weakly correlated in an individual, they seem to represent different aspects of sagittal cervical balance. The CVA cannot replace radiographically measured cervical lordosis. We recommend that more emphasis be given to radiographic measures of sagittal cervical alignment than the CVA when considering patient interventions.
Keywords: X-ray; cervical spine; craniovertebral angle; forward head posture; neck pain; sagittal balance.