Craniocervical Posture and Cervical Curvature Variations in Adult Females with Different Vertical Facial Patterns: A Cross-Sectional Study

This study aimed to determine whether there are relationships between vertical facial patterns, cervical posture, and cervical curvature types. Ninety-two adult females with skeletal Class I relationships were retrospectively analyzed and divided into hypodivergent, normovergent, and hyperdivergent groups based on the mandibular plane angle to the nasion–sella line. Variables representing craniocervical posture (sagittal vertical axis, SVA; cervical inclination angle, CIA) and cervical curvature were measured. Differences in craniocervical posture among the groups were assessed. Cervical curvatures were classified into lordotic, straight, kyphotic, or sigmoid categories. The distribution of cervical curvature types among the groups was compared, and correlations between vertical facial patterns, craniocervical postures, and cervical curvature measurements were calculated. The results indicated that the hyperdivergent group exhibited increased SVA and decreased CIA compared to the normovergent and hypodivergent groups. Significant differences in cervical curvature types were observed among the groups. Lordotic curvature was most common in the normovergent group, while straight curvature was predominant in the hypodivergent and hyperdivergent groups. A significant correlation was found between an increased mandibular plane angle and a forward head position (increased SVA and decreased CIA). In conclusion, there are relationships between vertical facial patterns, cervical posture, and cervical curvature types. Therefore, careful assessment of craniocervical posture and cervical curvature is necessary in lateral cephalograms for orthodontic evaluation. However, cervical curvature measurements show minimal correlation with the mandibular plane angle.