Zonography of the petrous temporal bone

The examination of the petrous temporal bone by zonography is presented. The prerequisite theoretical criteria for successful zonography are restated and applied to the radiological examination of the petrous bone. The technique is advocated as a screening examination for abnormalities of the internal auditory canals; as an important addition to hypocycloidal tomography in the investigation of congenital ear disease; for the evaluation of the incudo-mallear joint in the axial projection following trauma to the temporal bone; and for the demonstration of the temporo-mandibular joint.