Optic canal contents. The optic canals are openings in the lesser wings of the sphenoid bone just medial to the anterior clinoid processes. These contain the optic nerves and their dural sheaths. Each canal also transmits an ophthalmic artery, a branch off the intradural internal carotid artery. In the midline here is the pituitary gland covered by the diaphragma sellae. An aperture allows passage of the pituitary stalk or infundibulum to the hypothalamus. The oculomotor nerve enters the roof of the cavernous sinus through the oculomotor triangle. This is bounded posteriorly by the posterior petroclinoid dural fold, which extends from the petrous apex to the posterior clinoid process; laterally by the anterior petroclinoid dural fold, which extends from the petrous apex to the anterior clinoid process; and medially by the intraclinoid dural fold, which extends from the anterior to the posterior clinoid. (Image courtesy of PA Rubino)