Objective: To analyze the relationship between position of head, cervical curvature type and associated cervical balance parameters in a neutral looking-forward posture.
Methods: Cervical lateral X-rays of 60 patients with cervical spondylosis were selected from January to December 2015. There were 22 males and 38 females with an average age of (35.5±10.9) years old. The measured parameters included cervical curvature type, McGregor slope, C2 lower end plate slope, T1 slope, center of gravity to C7 sagittal vertical offset (CG-C7 SVA), and C2 to C7 sagittal vertical offset (C2-C7 SVA). The parameters were analyzed using Spearman correlation.
Results: The cervical curvature type was significantly correlated with C2 lower endplate slope, C0-C2 angle (total degree of C2 lower endplate slope plus McGregor slope), CG-C7 SVA and T1 slope (P<0.05), but it was not significantly correlated McGregor slope (P>0.05). C2 lower endplate slope and C2-C7 SVA (r=0.87) were significantly (P<0.05) correlated with CG-C7 SVA (P<0.05).
Conclusions: There was certain some relationship among position of head, cervical curvature type and associated cervical balance parameters in a neutral looking-forward posture. The center of gravity of the head would backwards shift following faced upward. A position of extension with posterior-shifting of the head would suggest that it may be accompanied with a relatively normal lordosis of the cervical spine. Some patients with abnormal curvature showed slightly bended head in the natural posture. Health education toward these people would be meaningful to restore the balance of their neck.
Keywords: Biomechanics; Cervical curvature; Radiographic measurement.