Methods One of adult male complete dentition was chosen, and then using Frankfort horizonal plane as benchmark , CT scanning was done from condylar process to mental region, 73 lamella in all.

• 方法：选用牙列完整的成年男性志愿者1例，以眶耳平面为基准平面进行螺旋CT扫描，从髁突到颏部连续横断扫描73层。