髁状突颈部骨折在面骨骨折中最常见,但是髁状突向上移位进入颅中四很少见。打击于下颌骨的外力多来自前方或侧方,致使一侧或双侧髁状突向后撞击下颌关节凹后壁,而后壁骨质致密,因而致使髁状突颈部发生骨折。但是如果打击于下颌角的外力是向上和稍向后,由于有后牙的咬(牙合)阻挡,下颌骨是不会向上移位的,只有当后牙发生牙折或被打入上颌窦内,或者当一侧或双侧后牙全部缺失时,关节四才有可能骨折。作者复习了过去55年来的英文文献,仅5例髁状突进入颅中凹的报告。作者再报告1例如下: Condylar neck fractures are the most common fractures of the face, but the displacement of the condyle into the cranial fourth is rare. Striking the external force of the mandible from the front or side, resulting in one or both of the lateral condyle striking the concave posterior wall of the mandibular joint, while the posterior wall of dense bone, resulting in condylar neck fractures. However, if the external force against the mandibular angle is upward and slightly rearward, the mandible does not shift upward due to the bite occlusion of the posterior teeth, only when the posterior teeth have an entanglement or are punctured into the maxillary sinus Or when one or both of the posterior teeth are missing, the joint four may fracture. The authors reviewed the English literature over the past 55 years and reported only 5 cases of condyle bump into the cranial cavity. The author then reports a case as follows: