Endoscopic view of anterior sellar region. The clivus and most of the sphenoid bone have been removed to reveal the basilar artery (formed by union of the right and left vertebral arteries) overlying the pons and several of its branches. These include the anterior inferior cerebellar arteries, several pontine arteries (not labeled), and the superior cerebellar arteries. Near the pontomedullary junction arise the abducens nerves and from the pons more anterolaterally the large trigeminal nerves. The convoluted course of the internal carotid arteries can be seen as these traverse the carotid canal and cavernous sinus before becoming intracranial medial to the anterior clinoid processes. Here, from its ophthalmic segment, it gives rise to the ophthalmic artery which enters the optic canal with the optic nerve to the orbit. The pituitary gland occupies a midline position between the cavernous internal carotids as it rests on the sella turcica. Within the cavernous sinus, the abducens nerve courses along the lateral surface of the ICA while the oculomotor nerve courses within the lateral wall of the sinus. The anterior cerebral arteries, terminal branches of the ICA, can be seen as they approach the interhemispheric fissure. (Image courtesy of AL Rhoton, Jr.)