Anatomical Dissection of the Clinoidal Segment of the Internal Carotid Artery. The dura mater has been removed over the optic canal, the middle fossa, and lateral aspect of the cavernous sinus. The tentorium cerebelli has been cut and reflected posteriorly to show the course of the cranial nerves through the cavernous sinus. The anterior clinoid process has been removed to expose the clinoidal segment of the ICA. Bone has been drilled posterior to the intrapetrous ICA to expose the superior semicircular canal, the cochlea, and the geniculate ganglion. (Image courtesy of E de Oliveira)