目的 通过颈椎CT影像与内镜下寰、枢椎齿突解剖，为内镜下颅颈交界区手术提供依据。   方法 选取150例颈椎高分辨薄层平扫CT测量评估寰枢椎及其毗邻结构关系，估算齿突切除术安全界。3例新鲜灌注尸头，采用STORZ内镜系统及内镜手术器械，经下颌下入路行内镜下寰枢椎齿突解剖。   结果 通过CT测量得出寰椎前弓长度均值等，估算齿突切除安全界面积为(240.9±39.92)mm2，其中男性(248.3±49.64)mm2，女性(233.2±24.54)mm2。经下颌下的内镜入路寰枢椎解剖及齿突切除解剖以一侧下颌角与舌骨连线中点处横行切口，显露下颌下三角区域，内镜下经下颌下三角区暴露二腹肌及舌骨大角，沿咽后间隙逐层钝性分离至椎前间隙，暴露椎前筋膜，去除椎前组织后充分暴露寰椎、枢椎齿突、寰枕关节、寰枢关节、及部分枕骨大孔区。   结论通过CT影像学估算齿突切除的安全界面积，结合内镜下颌下入路解剖暴露寰枢椎齿突，在内镜的明视下进行有效、安全的手术器械操作，提示经内镜下颌下入路切除齿突在实现充分减压的同时又能极大程度降低脑脊液漏的发生率，减少感染的机会。

Objective To provide the basis for endoscopic craniocervical junction surgery through cervical CT image and endoscopic odontoid process anatomy of atlas, axis and odontoid.   Methods A total of 150 cases of cervical vertebrae were selected for high resolution thin slice plain CT measurement to evaluate the atlantoaxial structure and its adjacent structure, and to estimate the safe boundary of odontoid process resection. The atlantoaxial odontoid process was anatomized on 3 cadaver head specimens under endoscope through the submandibular approach using STORZ endoscopy system and endoscopic surgical instruments.  Results The average length of atlas anterior arch and other anatomical marks were measured by CT, and the safety boundary area of odontoidectomy was estimated to be (240.9 ± 39.92)mm2, male: (248.3 ± 49.64)mm2, Female: (233.2 ± 24.54)mm2. Through the submandibular endoscopic approach, the atlantoaxial anatomy and odontoidectomy anatomy made a transverse incision at the midpoint of the connecting line between one mandibular angle and hyoid bone to expose the submandibular triangle area. Under the endoscope, the digastric muscle and the greater angle of hyoid bone were exposed through the submandibular triangle area, and the retropharyngeal space was passively separated layer by layer to the prevertebral space to expose the prevertebral fascia. After removing the prevertebral tissue, the atlas, the dentate process of the axis, the atlantooccipital joint, the atlantoaxial joint, and part of the foramen magnum were fully exposed.  Conclusion Estimating odontoid resection safety boundary area by CT image, in combination with endoscopic odontoidectomy anatomy via sunbmandibular approach, we can perform the surgery safely and efficiently under the bright of endoscope with surgical instruments, which can significantly reduce the incidence of cerebrospinal fluid leakage and postoperative infection while decompressing.