目的：使用CT影像研究中国北方正常人群的面部比例及对称性，为正颌外科手术设计提供参考。方法：选取60名颅颌面骨骼肌咬合关系正常的北方志愿者拍摄头面部CT，使用Proplan 1.2软件对CT影像进行三维重建，采用三维头影测量分析北方正常人群的面部比例以及面部对称性，使用t检验比较性别差异。结果：所有线距测量值男性均大于女性（P<0.05），比例测量值则多数无明显性别差异（P>0.05）。男性和女性颅颌面结构的非对称率均小于10%，且无性别差异（P>0.05）。结论：使用CT影像数据进行三维头影测量可以较好地分析面部比例及对称性。正常的颅颌面三维结构之间符合特定的数学比例，建立正常人群的颅颌面三维结构数据库可以为颅颌面畸形的诊断及治疗设计提供标准和参考。

Objective：To investigate the internal regularities and symmetry of craniofacial structures from adults with normal occlusion in North China.Methods:The study consisted of 60 volunteers who were examined with spiral 3D computed tomography (CT). The axial images of craniofacial structure were reconstructed into 3D models and analyzed by using Proplan 1.2 software to measure the internal regularities and symmetry of craniofacial structures. Results: All the linear measurement’s value of the males were bigger than those of the females (P<0.05). There were no significant differences in the ratio measurements between the males and the females(P>0.05). Facial asymmetry was less than 10% in all the images. Conclusion: CT is an effective method for three-dimensional analyses of craniofacial structure and symmetry. There are certain and harmonious regularities in normal 3D craniofacial structures. The 3D craniofacial structure database of people with normal occlusion can provide standards and references for diagnosis and treatment planning of craniofacial deformities.