Osseous anatomy of the posterior skull base. The dorsum sellae of the sphenoid bone and the clival part of the occipital bone form the clivus. The lateral or condylar part of the occipital bone comprises the jugular tubercle, the jugular notch or posterior margin of the jugular foramen, jugular process, hypoglossal canal, and condyle. Note the gap for the petrous portion of the temporal bone. (Image courtesy of JC Fernandez-Miranda)