Anterior view of sellar and parasellar regions. The clivus and body of sphenoid have been removed to reveal associated structures. The middle of the lower part of the image shows the basilar artery overlying the pons and the basilar venous plexus. The anterior wall of the sella turcica has been removed to show the pituitary gland. Superiorly, the intercavernous sinus courses within the diaphragma sellae. Lateral to the pituitary gland along the lateral walls (removed) of the sphenoid body are the cavernous segments of the internal carotid arteries. These are continuations of the petrous segments traversing the carotid canals. Both segments carry the perivascular carotid sympathetic nerve plexus. Arising from this segment of the artery is the capsular (McConnell's) artery supplying the sella dura mater and capsule of the anterior pituitary. The meningohypophyseal trunk also arises from this segment proximal to the origin of the capsular branch. It supplies the posterior pituitary and meninges overlying the clivus and tentorium. Distal to the distal dural ring, the cerebral or supraclinoid segment of the internal carotid artery gives rise to the superior hypophyseal artery to the optic nerve and chiasm, the pituitary stalk and gland, and the ophthalmic artery to the orbit. (Image courtesy of AL Rhoton, Jr.)