Cephalometric Study on the Morphology of the First Cervical Vertebra to Craniofacial Structures.
(Part 1): Is There Any Relationship ?


Ronaldo G. Vergara, Tamaki Mohri, Shuichi Morita and Kooji Hanada
Department of Orthodontics, School of Dentistry, Niigata University (Chairman: Prof. Kooji Hanada)


Abstract :
  The use of cervical vertebrae to evaluate the individual craniofacial development has been considered by some investigators. The first cervical vertebral (atlas) morphology that was reported to reflect the head posture, could be used as an indicator of craniofacial growth and development on Caucasian samples.
  The aim of the investigation was to establish a norm of atlas measurements, mean and standard deviation in Japanese school chidren ages' 7, l0, 12 and 15 and to clarify the associations of the atlas morphology with craniofacial structure (CFS) at these ages.
  One hundred ninety six lateral head films of 49 school children (30 males and 19 females) at age 7, 10, 12 and 15 were traced and measured at 5 variables for the atlas and 12 variables for CFS. The significance of correlation of the atlas variables with that of CFS was statistically analyzed. Facial diagram of subjects that was divided according to the height of the dorsal arch into high and low group was compared and analyzed.
  Data revealed a statistically significant increase in atlas morphological dimension as it undergoes incremental growth change and that a characteristic craniofacial structural differences exist between sex and age. It was observed that a pattern of statistically significant correlation exists on both sexes between the height of the dorsal arch, antero-posterior length and atlas ratio (index) with CFS variables. The association was observed in the vertical position of the mandible among males that was not found among females except on the maxillo-mandibular relations and rotation of the mandible. The pattern of CFS and its association with the atlas morphology were altered with sex and age.
  It was established from the results in this study that the association of the atlas morphology with CFS and its growth pattern among Japanese samples, were more vertical mandibular position in males while, in female, a trend of maxillo-mandibular rotation instead of horizontal mandibular position that was reported among Caucasian samples. The association of the first cervical vertebra with CFS and CFS growth pattern itself was different according to race, sex and age. Thus, the factor of sex, race and age should be carefully considered in the application of the atlas morphology as one of the indicator of CFS growth.


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