Natural cervical inclination and craniofacial structure.

The purpose of this study was to search for the statistical associations between postural and morphologic variables of the head. Interpretation of the facial structure was made by using both intracranial and the extracranial reference lines. The sample comprised natural head posture (NHP) cephalograms of 106 dental students, aged 19 to 29 years. Results showed that, when the facial structure was evaluated by using a NHP analysis based on extracranial reference lines, it was associated with the inclination of the cervical column to the true horizontal. In addition, in the natural position of the head, inclination of the NSL reference was found to be associated with the vertical localization of sella turcica (r = -724, p < or = 0.001), rather than the "extension" or "flexion" of the head. It was concluded that associations between posture and structure of the head are merely caused by the functional factors related to "forward cervical posture" and "vertical cervical posture".