在开颌运动中,根据下颔运动轴心的位置不同,将其分为三个阶段、即小开颌、大开颌和最大颌。在大开颌时,下颌以下颔小舌处为轴心旋转,关节区则以髁状突偕关节盘沿关节结节后斜面滑行,下颌则表现为下降。这一论述为众多人所接受,但其具性原理则报导甚少。为此,本文特随机抽取整颅样本,作有关数据的测量,用公式诱导的方法,阐述大开颌时的轴心位置. In the jaw movement, according to the position of the axis of Xialu movement is different, it is divided into three stages, namely, small jaw, jaw and the largest jaw wide jaw. In the case of a large jaw, the mandible below the small tongue as the axis of rotation, the joint area to the condylar kytopathic joint disk along the joint nodular incline ramp, the lower jaw showed decline. This discourse is accepted by many people, but its principle of principle is poorly reported. To this end, this article special random sampling of the entire skull, for the measurement of data, the formula induced by the method to explain the axial position when the jaw wide open.