Interdural transcavernous approach to the upper clivus. The posterior clinoidectomy has been completed to expose the dura of the roof of the cavernous sinus, or oculomotor triangle dura. The interclinoidal ligament forms the medial limit of the oculomotor triangle and serves as a reference for the interdural segment of the oculomotor nerve, located infero-lateral to the ligament. (Image courtesy of JC Fernandez-Miranda)