Imaging of the External Auditory Canal: A Pictorial Review

The external auditory canal (EAC) is composed by a cartilaginous and an osseous portion. Although it is a pathway, mainly communicating with the tympanic cavity, the EAC is bordering many spaces such as the temporomandibular joint, the temporal bone proper, skull base and the intracranial compartment. Although it can be accessed via clinical exam, there are instances where the view is obstructed, or the clinicians might suspect deeper pathologic involvement or need pre-operative evaluation. CT, MRI and Nuclear Medicine have a role in those cases. Pathologies can include infectious, malignant, epithelial or traumatic lesions, and among others, congenital processes can also affect the external auditory canal. The aim of this review is to familiarize the reader with anatomic landmarks, and to correlate them with important pathologic processes and their imaging findings.