目的：研究内镜辅助下经口咽旁间隙手术的可行性与安全性，对比经口路径与经颈部路径的解剖差异，并制定一套可行性方案。方法：完整解剖一例尸头（左右两侧），分别从经口路径和颈外路径进路逐层解剖到咽旁间隙及颌下间隙，了解经口路径和经颈外路径在解剖层次上的不同，在暴露重要神经、血管上有何差异。结果：前间隙位于咽上缩肌与翼内肌之间，向后以茎突的三块肌肉与后间隙分隔。经口路径咽上缩肌是进入前间隙的重要标志，茎突舌骨肌、茎突舌肌和茎突咽肌是前后间隙分界的重要标志，后间隙包含很多重要神经、血管。

根据经口路径解剖时所能暴露的情况以及照明情况，我们人为的将咽旁间隙分为两部分：上部：硬腭平面以上，颅底以下，此部分因硬腭阻挡，在不去除硬腭的情况下暴露及照明都较难； 下部：硬腭平面以下至舌骨水平，此部分用0度镜头可以很好暴露，部分区域需要30度内镜镜头或者70度内镜镜头辅助，但是能清楚暴露该部位的神经、血管。经颈部路径：二腹肌后腹是进入咽旁间隙的重要标志，下颌角平面是副神经进入胸锁乳突肌的标志。结论：内镜辅助下经口路径对硬腭平面以下的咽旁间隙可多角度、高清晰暴露各血管、神经及肌肉，有助于术中识别及保护，肿瘤也可清晰暴露。内镜辅助下经口路径对硬腭平面以上咽旁间隙暴露较差，同时也意味着手术难度较大，但是经颈部路径对硬腭平面以上咽旁间隙神经、血管暴露较清晰，但是经颈部入路容易损伤面神经网，导致部分面瘫。

Obsjective: To study the fesibility and safety of the transoral approach to parapharyngeal space surgeries, to contrast the difference between transoral approach and transcervical approach, and develope  guidelines for PPS surgeric approaches.Methods: A cadaveric head transected at the C7-T1 level was procured for the study. I did the anatomy for both sides via transoral approach and transcervical approach, and compared the similarities and differences between transoral approach and transcervical approach to find out which approach was more preferable removing tumors from PPS. Results: The prestyloid space locates between  superior constrictor muscle and medial pterygoid muscle. Styloid process and its muscles divide the prestyloid space from the retrostyloid space. Superior constrictor muscle is an important mark for entering the prestyloid space, and the styloglossus muscle, stylohyoideus muscle, and stylopharyngeus muscle divide the PPS into 2 different compartments.Retrostyloid contans the ICA, the IJV, the IX, X, XI, and XII cranial nerves, the sympathetic chain, fat, and some lymph nodes. According to the reveal and illumination of the transoral anatomy,we divided the PPS into two compartments. The superior one locates between skull base and hard palate, which is obstructed by the hard palate. So it is hard to reveal unless we remove the hard palate. The inferior compartment locates between the hard palate and the hyoid bone. This part was easy to anatomy with the help of 0^o endoscope,and we had a good vision for the vatal vessels and nerves.And we didn’t damage any other tissues,or just need to remove part soft tissues. The posterior belly of the Digastric muscle is an important mark to enter the retrostyloid space via transcervical approach. Mandibular angle is the place where accessory nerve enters the sternocleidomastoid muscle. 

Conclusion: Endoscope-assisted transoral apporach to PPS has a good vision for vessels and nerves of the middle and inferior part of PPS, which is helpful when doing a transoral surgery. However, it doesn’t have a good vision for the superior part of PPS, which means it is harder to remove tumors derive that compartment. But, transcervical approach can have a good vision to that part。A transcervical approach need to remove part facial never when facing tumors derive from that part.