Abstract: It is very important to select the appropriate surgical approach in the operation of endoscopic skull base surgery. There are two principles: (1) the field of view should be well exposed; (2) the important neurovascular injury should be avoided. In the endoscopic endonasal approach to the lateral midline skull base, the anatomical structures of the pterygoid process, the vidian canal, the foramen rotundum, the foramen ovale and the eustachian cushion are relatively fixed. By the endoscopic endonasal transpterygoid approach, we can handle the pterygopalatine fossa, infratemporal fossa, cavernous sinus, Meckle cavity, paraclival to cavernous segment of internal carotid artery, petroclival region, petrous apex, eustachian tube area, and the upper parapharyngeal space. Pterygoid process can be used as the anatomical landmark for endoscopic skull base surgery and be chosen as the operation center for inward and outward expansion. Making full use of the space location, increasing the sense in the operation of three-dimensional space, is helpful in expanding the endoscopic skull base surgery.

Key words: Pterygoid process, Anatomy, Lateral midline skull base, Endoscopic surgical procedures, operative