Surgical anatomy of the optic nerve and the internal carotid artery in the lateral wall of the sphenoid sinus. An anatomic study of the cranial base]

The optic nerve and the internal carotid artery lying in the cavernous sinus contact the bony wall of the sphenoid sinus, and can easily be injured during surgery. The maxillary sinus, the sphenoid sinus and the ethmoid cells were opened on both sides during ten resections of the skull base. After removing the bony part of the lateral wall of the sphenoid sinus the following measurements were performed: the distance between the optic nerve and the frontal dura; the distance between the optic nerve and the internal carotid artery; the length and width of the optic nerve and the internal carotid artery in the area contacting the bony wall of the sphenoid sinus. This study illustrates the regularity of the structures of the posterior nasal wall. Landmarks are offered for finding the orbital aperture of the optic canal. The necessity of orientation by landmarks is emphasized.