Cisternography with metrizamide (Amipaque) and hypocycloidal tomography was found to depict cisternal anatomy with detail and precision not obtainable with any other technique. Clinical tolerance is comparable to that of encephalography if suitable precautions are followed. All side effects observed had disappeared 36 hours after injection, and no delayed noxious effects were recorded. This method offers a simple, rapid and precise technique for depicting cisternal anatomy and requires no equipment other than a tilting multidirectional tomographic unit.