下颌角前切迹的最低点至下颌平面（由下颌骨下绿的两个最突点连接而成）的垂直距离定义为下颌角前切迹的深度，深度大于或者等于3mm者为深切迹组，深度小于或者等于lmm者为浅切迹组。本研究分别测量了40例深切迹组和40例没切迹组患者治疗前的头影测量片以探究其与颅面骨骼形态 The vertical distance from the lowest point of anterior notch of mandibular angle to the mandibular plane (connected by the two most protruding points of the lower green of the mandible) is defined as the depth of the anterior notch of the mandibular angle, the deep notch group of depth greater than or equal to 3mm , The depth of less than or equal to lmm were shallow notch group. In this study, 40 cases of deep notch group and 40 cases of non-notch group were measured before treatment cephalometric film to explore its relationship with the craniofacial skeleton