Anterior perspective of sellar and parasellar anatomy via transnasal endoscopy. The pituitary gland is contained within the sella turcica of the sphenoid bone. Lateral to this is the cavernous sinus containing the cavernous segment of the internal carotid artery. The carotid sympathetic nerve plexus can be seen on the surface of the artery. The abducens nerve courses on the lateral surface of the internal carotid artery within the cavernous sinus. Within the lateral wall of this sinus are the oculomotor, ophthalmic, and maxillary nerves. The oculomotor, ophthalmic, and abducens nerves converge on and traverse the superior orbital fissure to enter the orbit, while the maxillary nerve passes through the foramen rotundum to enter the pterygopalatine fossa. Superior to the pituitary gland is the optic chiasm and optic nerves coursing toward the optic canals in company with the ophthalmic artery, the first branch of the internal carotid artery distal to the cavernous sinus. (Image courtesy of AL Rhoton, Jr.)