Superior view of the anterior cranial fossa and optic nerves. The anterior cranial fossa consists of the orbital plates of the frontal bone, cribriform plate of the ethmoid bone, and the lesser wing of the sphenoid. Between the outer and inner tables of the frontal bone is the frontal sinus. The olfactory bulbs rest upon the cribriform plates, which are separated by a vertical crest of bone, the crista galli. The falx cerebri attaches to this crest. Medial to the anterior clinoid processes are the optic canals for entrance of the optic nerve and ophthalmic artery. The supraclinoid segment of the internal carotid artery is shown dividing into the anterior and middle cerebral arteries. A very short anterior communicating artery connects the right and left anterior cerebral arteries. (Image courtesy of AL Rhoton, Jr.)