The cranial vertical angle (CVA) and cranial rotation angle (CRA) are used in clinical settings because they can be measured on lateral photographs of the head and neck. We aimed to clarify the relationship between CVA and CRA photographic measurements and radiographic cervical spine alignment. Twenty-six healthy volunteers were recruited for this study. Lateral photographs and cervical spine radiographs were obtained in the sitting position. The CVA and CRA were measured using lateral photographs of the head and neck. The C2-7 sagittal vertical axis (SVA), cervical lordosis (C2-7), and occipito-C2 lordosis (O-C2) were measured using radiographic imaging as a standard method of evaluating cervical spine alignment. Correlations between the CVA and CRA on photographs and cervical spine alignment on radiographs were analyzed. The CVA and SVA were significantly negatively correlated (ρ = −0.51; p < 0.05). Significant positive correlations were found between CVA and C2-7 (ρ = 0.59; p < 0.01) and between CRA and O-C2 (ρ = 0.65; p < 0.01). Evaluating the CVA and CRA on photographs may be useful for ascertaining head and neck alignment in the mid-lower and upper parts of the sagittal plane.

Objective: To compare forward head posture (FHP) in natural and corrected head postures between patients with nonspecific neck pain (NSNP) and controls, and to clarify the relationship between natural- and corrected-head posture angle differences and deep cervical flexor function. Design: Survey study Setting: Patients with NSNP were outpatients at an orthopedic clinic; the controls were community volunteers. Participants: Thirty-eight patients were divided into the NSNP and control groups (n=19 each), including patients reporting a numerical rating pain score of 3-7 for at least 3 months and those with no neck pain within 12 months previously, respectively. Interventions: To evaluate FHP, the cranial rotation and vertical angles were measured using lateral photographs of the head and neck. The craniocervical flexion test was used to evaluate deep cervical flexor activation and endurance. Main outcome measures: We evaluated the head and neck alignment in natural and corrected head postures and the relationship between the degree of change and deep cervical flexor function. Results: The FHP in the natural head posture did not differ significantly between the groups. For corrected head posture, the FHP was significantly smaller in the NSNP group than in the control group. In the NSNP group, the cranial rotation and vertical angles were significantly different between natural and corrected head postures, and the angle difference between these postures was significantly correlated with deep cervical flexor function. Conclusions: In patients with NSNP, hypercorrection in the corrected head posture was shown and may be correlated with dysfunction of the deep cervical flexors. Further investigation into the causal relationship between hypercorrection, deep neck flexor dysfunction, and neck pain is required.