A, Sagittal section to right of the midline. The nasal septum, along which the transsphenoidal approach is directed, is formed above by the perpendicular plate of the ethmoid, anteriorly by the nasal septal cartilage, and below by the vomer. The vomer articulates with the anteroinferior part of the sphenoid body, and the perpendicular plate articulates with the anterior face. The sphenoid sinus is located in the body of the sphenoid bone. B, The sagittal section has been extended to the right of the midline. The nasal concha and meatus and the eustachian tubes are in the lateral margin of the exposure. C, Portion of the middle and inferior turbinates has been removed. The ostia of the maxillary and frontal sinuses opens into the middle meatus located below the middle turbinate. The nasolacrimal duct opens below the lower turbinate into the inferior meatus. Rosenmüller’s fossa is located behind the eustachian tube. D, The mucosa in the lateral margin of the nasal cavity and the posterior part of the inferior and middle turbinates have been removed to expose the pterygoid process and the posterior maxillary wall, which form the posterior and anterior boundaries of the pterygopalatine fossa, respectively. The eustachian tube opens into the nasopharynx at the posterior edge of the pterygoid process. The terminal branches of the maxillary artery pass through the pterygopalatine fossa, located between the posterior maxillary wall and the pterygoid process, to enter the posterosuperior part of the nasal cavity at the anteroinferior margin of the sphenoid sinus. The medial wall of the pterygopalatine fossa is formed by the perpendicular plate of the palatine bone. E, The medial wall of the maxillary sinus has been opened to expose the infraorbital nerve, which arises in the pterygopalatine fossa and passes forward in the sinus roof. The maxillary nerve passes through the foramen rotundum to enter the pterygopalatine, where it gives rise to the infraorbital, zygomatic, and greater palatine nerves, plus communicating rami to the pterygopalatine ganglion. F, Enlarged view. The bone and dura covering the optic canal in the superolateral part of the sphenoid sinus has been opened to expose the optic nerve and ophthalmic artery in the optic canal. The junction of the petrous and cavernous carotid limits the exposure below the level of the sella. Terminal branches of the maxillary artery intermingle with the neural structures in the pterygopalatine fossa and exit the fossa to supply the tissues on the sphenoid face. (Images courtesy of AL Rhoton, Jr.)