Using 3 dimensional dental iCAT cone beam scans to assess and instruct temporal bone anatomy

Abstract

The temporal bone is one of the most difficult bones for students in head and neck courses to learn. These paired bones help form the base and lateral walls of the skull in addition to housing the auditory and vestibular apparatus. Each temporal bone has eight centers of ossification which give rise to the three major centers which are observed prior to birth. There are four major parts of the temporal bone: the squamous, petrous, tympanic, and styloid process. The squamous and tympanic portions develop from intramembranous bone formation whereas the petrous portion and styloid process develop from endochondral bone formation. The temporal bone is very complex, as it also houses the internal jugular vein, internal carotid artery, facial nerve and branches, and the vestibulocochlear nerve. However, these structures are lost in disarticulated bones. While the anatomy of the temporal bone can be appreciated from the disarticulated skull, the internal anatomy of the bone is difficulty to observe unless careful dissection is performed. The iCAT cone beam scans allow for 3 dimensional reconstruction of the skull. In our study, we performed iCAT cone beam scans on both disarticulated temporal bones and cadavers to reconstruct the anatomy of the temporal bone for instruction to dental students. This imaging technique allowed us to teach the clinical anatomy of the temporal bone including the auditory ossicles and semicircular canals in situ. Canals such as the internal acoustic meatus, external meatus, and facial canal were easily traced to explain the path of internal structures. This imaging modality serves as an excellent adjunct in learning the anatomy of the temporal bone.