The first cervical vertebra as an indicator of mandibular growth.

The association between the morphology of the first cervical vertebra, the atlas, and the direction of mandibular growth is studied by analysing two sets of lateral roentgenocephalograms--one comprising 18 non-treated children and another comprising 18 orthodontically treated subjects divided into three groups with regard to mandibular growth rotation. Among the non-treated cases there was a significant correlation between horizontal growth of the mandible during a two-year period and the initial height of the atlas dorsal arch. The treated subjects with forward mandibular rotation during treatment, demonstrated a significantly higher pretreatment dorsal arch than the subjects with either no rotation or a backward mandibular rotation.