A, A lateral rhinotomy incision has been extended along the medial orbital rim. The medial canthal ligament has been exposed. B, The medial canthal ligament has been divided to expose the medial aspect of the orbit. The ligament can be preserved and the medial orbital wall left intact if orbital exposure is not needed. The anterior pyriform aperture is exposed. C, The osteotomies are as outlined to open the nasal cavity and medial maxilla. The medial one opens the nasal cavity and the lateral bone removal exposes the maxillary sinus. The medial maxillotomy aids in exposing the clivus. D, The exposure has been directed to the posterior nasopharyngeal wall behind which the clivus sits. The anterior wall of the sphenoid sinus has been removed, exposing the sphenoid septum. The posterior part of the nasal septum has been removed to expose the clivus below the sphenoid sinus. Removal of the medial part of the posterior wall of the maxillary sinus exposes the maxillary artery in the pterygopalatine fossa. E, Enlarged view of the pterygopalatine fossa exposed by removing the medial part of the posterior wall of the maxillary sinus. The maxillary nerve and artery enter the pterygopalatine fossa. The maxillary artery is the major source of bleeding during surgery in this area. The maxillary artery enters the pterygopalatine fossa by passing through the pterygomaxillary fissure. The maxillary nerve enters the fossa by passing through the foramen rotundum and gives off communicating rami to the pterygopalatine ganglion. F, The pharyngeal mucosa has been opened, the longus capitis reflected laterally, and the clivus and dura opened to expose the basilar artery ascending in front of the pons. The pituitary gland is at the upper margin of the exposure. (Images courtesy of AL Rhoton, Jr.)