Figure 3 Endoscopic view after drilling of pterygoid base and medial and lateral pterygoids. The spine of sphenoid (SS) still obscuring foramen spinosum, bony Eustachian tube and tensor tympani canal (TC). The carotid foramen (CF) cannot be visualized due its anterior superior and lateral direction. The bone between FO: foramen oval and bony Eustachian tube (BE) is formed by tubal process of tympanic bone (TP). Laterally the tympanic bone gives a vaginal process to enclose the styloid process (SP). PP: Petrous pyramid, clivus, JF: Jugular foramen, FS: Foramen spinosum, HC: hypoglossal canal.