Craniocervical Posture Assessed With Photogrammetry and the Accuracy of Palpation Methods for Locating the Seventh Cervical Spinous Process: A Cross-sectional Study.

OBJECTIVE: The purpose of this study was to compare craniocervical posture assessed by photogrammetry using 2 distinct palpation methods for locating the spinous process of the seventh cervical vertebra (C7SP). METHODS: This cross-sectional study was conducted in 2 phases. In phase I (n = 42), the assessor's accuracy in locating the C7SP using the flexion-extension and the modified thorax-rib static methods was compared to radiography. In phase II (n = 68), the craniocervical posture was analyzed with photogrammetry after palpation using the 2 methods. Neck pain intensity and disability were also determined. RESULTS: The accuracy in locating the C7SP was higher using the modified thorax-rib static method (67%, 95% confidence interval [CI], 55-79) compared to the flexion-extension method (38%, 95% CI, 26-50, P = .016). Lower values of the craniocervical angle were obtained with the flexion-extension method than the modified thorax-rib static method (mean difference = -1.1°, 95% CI, -1.6 to -0.6, P < .001). However, both palpation methods resulted in similar classifications of participants as with or without forward head posture (P = .096). Weak correlations were observed between the craniocervical angle and neck pain intensity (ρ = -0.088 and -0.099, respectively) and disability (ρ = -0.231 and -0.249, respectively). CONCLUSION: Craniocervical angles obtained using palpation methods with different accuracies were different, although the magnitude of the difference was insufficient to lead to different classifications of a forward head posture in adults with mild neck pain and disability. Craniocervical posture was weakly correlated with neck-pain intensity and disability.