Overview of the anatomy of the clival region in the coronal plane. The upper clivus is located behind the pituitary gland and relates laterally with the cavernous sinus. The middle clivus is limited laterally by the paraclival ICA, and relates laterally with the middle cranial fossa and the second division (V2) of the trigeminal nerve. The floor of the sphenoid sinus marks the transition between middle and lower clivus. The nasopharyngeal mucosa has been removed to expose the longus capitis and longus colli muscles, which cover the lower or “nasopharyngeal” clivus. The Eustachian tubes, which are located laterally in the nasopharyx, have been partially removed to better identify the foramen lacerum. The lower clivus relates laterally with the parapharyngeal ICA and the infratemporal fossa, where branches of the internal maxillary artery and the third trigeminal division (V3) can be identified. (Image courtesy of JC Fernandez-Miranda)