ATLAS MORPHOLOGY IN RELATION TO CRANIOFACIAL MORPHOLOGY AND HEAD POSTURE

The associations between dimensions of the first cervical vertebra, at las, and a representative set of craniofacial and postural variables w ere studied on cephalometric radiographs of a sample of 103 adult male s aged 22-30 years, recorded in the natural head position (mirror.posi tion). Atlas morphology was expressed by nine variables, linear and an gular craniofacial dimensions by 27 variables, and head and cervical p osture by seven variables. A pattern of low but significant correlatio ns was found. Although the correlations were low, the study confirmed that the dimensions of the atlas vertebra reflect associations between cranio-cervical posture and craniofacial morphology. Negative correla tions were found between the height of the posterior arch of atlas and the inclination of the mandible and the maxilla to the anterior crani al base. Low positive correlations between the height of the anterior arch and vertical facial dimensions reflect the general co-ordination of the vertical growth of the face and the cervical column. Moreover, the pattern of correlations between the atlanto-cranial angle and faci al morphology suggests that in changes of the cranio-cervical angle, a tlas follows the cervical column.