Endoscopic view of anterior midline neurovascular structures of the head. Extensive bone removal in the anterior midline of the head has exposed several structures. The frontal lobes of the cerebrum can be seen on the floor of the anterior cranial fossa. Between these, in the interhemispheric fissure, are the right and left anterior cerebral arteries. The optic nerves can be seen coursing toward the optic canals. Posterior to the optic chiasm is the pituitary stalk connecting the pituitary gland to the hypothalamus. Along the lateral surface of the sphenoid body (removed) are the internal carotid arteries coursing within the cavernous sinus. Along their lateral surface course the abducens nerve (CNVI). The supraclinoid or ophthalmic portion of the internal carotid artery gives rise to the ophthalmic artery, which accompany the optic nerves into the orbit. The clivus has also been resected to show the pons and the overlying basilar artery, which forms by union of the vertebral arteries at the pontomedullary junction.  The maxillary nerve can be seen coursing in the lateral wall of the cavernous sinus. (Image courtesy of AL Rhoton, Jr.)