Transoral view of retroclival structures and sella turcica. The clivus and parts of the sphenoid and petrous temporal bones have been removed to reveal the basilar artery (formed by right and left vertebral arteries uniting at the pontomedullary junction) ascending on the pons midline. Adjacent and posterior to the basilar artery is the medial anterior pontomesencephalic vein, which marks the anterior border of the brainstem in the lateral view. From the basilar artery arise the anterior inferior cerebellar arteries, several pontine arteries, and the superior cerebellar arteries. Near the pontomedullary junction arise the abducens nerve and from the pons more anterolaterally the large trigeminal nerve. Within the cavernous sinus, the abducens nerve courses along the lateral surface of the ICA toward the superior orbital fissure. The area of the sella turcica reveals the anterior and inferior intercavernous sinuses connecting the right and left cavernous sinuses. The right side of the image shows the exit if the jugular foramen with the internal jugular vein, glossopharyngeal, vagus, and spinal accessory nerves, and jugular and clival branches of the neuromeningeal trunk of the ascending pharyngeal artery. (Image courtesy of PA Rubino)