Cervical sagittal alignment differences according to scapular rotational posture

Scapular posture may influence cervical biomechanics because of the anatomical and functional linkage between the cervical spine and the scapulothoracic complex. Although abnormal scapular positioning has been associated with neck pain and altered muscle activity, radiographic evidence describing the relationship between scapular rotational posture and cervical sagittal alignment remains limited. Therefore, this study aimed to compare cervical sagittal alignment parameters between patients with upward rotation (UR) and downward rotation (DR) scapular postures. We retrospectively analyzed cervical spine X-ray images obtained from patients presenting with neck-related symptoms. Participants were classified into UR and DR groups according to scapular rotational posture. Cervical sagittal alignment parameters, including the C0-C2 angle, C2-C7 Cobb angle, C2-C7 sagittal vertical axis (SVA), K-line tilt, and functional spinal unit angles, were measured. Data were analyzed using independent t-tests, Pearson correlation analysis, multivariable logistic regression analysis and area under the curve as appropriate. Thirty-six patients (UR: n = 24; DR: n = 12; mean age, 44.64 ± 15.54 years) were included, of whom 58% were female. Compared with the UR group, the DR group showed greater C2-C7 SVA (P = .01, d = .94), greater K-line tilt (P = .03, d = .79), and a smaller C4-C5 functional spinal unit angle (P = .04, d = .74). No significant differences were found in other cervical alignment parameters. Scapular rotational posture was negatively correlated with C2-C7 SVA (r = -.562, P < .001) and K-line tilt (r = -.452, P = .007). C2-C7 SVA independently predicted DR posture (odds ratio = 1.109, 95% confidence interval = 1.013-1.214, P = .025) and demonstrated acceptable discrimination (area under the curve = 0.75, 95% confidence interval = 0.56-0.94). Downward scapular rotation is associated with altered cervical sagittal alignment, particularly increased anterior cervical translation and segmental changes at the C4-C5 level. These findings highlight a potential biomechanical interaction between scapular rotational posture and cervical sagittal balance, suggesting that evaluation of scapular posture may provide clinically relevant information when assessing cervicoscapular dysfunction in patients with neck pain.