Superior view of sellar region. The sella turcica containing the pituitary gland is shown. Its overlying diaphragma sellae has been resected to expose the gland. Normally, an aperture in the roof of this dural fold transmits the pituitary stalk to the hypothalamus. Lateral to the sella is the cavernous segment of the internal carotid artery. The distal dural ring is a layer of dura that is continuous with the dura covering the superomedial aspect of the anterior clinoid process and the tuberculum sellae (not labeled).  At the level of the distal dural ring, the ICA becomes intracranial and gives rise to the ophthalmic artery, which enters the optic canal with the optic nerve. The oculomotor nerve is exposed after having penetrated dura covering the roof of the cavernous sinus. It courses to the orbit through the superior orbital fissure. (Image courtesy of PA Rubino)