The clivus is a bone of the central skull base formed from the basisphenoid and the basiocciput. During normal ageing, the clival marrow converts from haematopoietic with low-to-intermediate T1 signal to fatty high T1 signal. Low T1 signal in adults is a marker of disease. This review illustrates the main important diseases of the clivus. Chordoma, fibrous dysplasia, myeloma, and metastasis arise within the clivus. Chondrosarcoma, nasopharyngeal carcinoma, invasive pituitary macroadenoma, cholesteatoma, and mucocele can be recognized from attention to adjacent structures. Although some diseases have overlapping appearances, there are several defining features that suggest a single diagnosis. A table is presented summarizing the differentials of the main distinguishing features.