The internal auditory canal (IAC) is a bony canal that contains nerves and vessels and is lined by meninges. Pathologic processes may arise from each of these structures. Congenital, developmental, and acquired pathologic conditions may involve the bone of the canal and lead to excessive narrowing or expansion. Lesions formed within the canal include hemangiomas, vascular malformations, and inflammatory and neoplastic processes arising from the facial and acoustic nerves and meninges. Finally, other rare lesions, such as choristomas and metastases, may occur within the IAC, which are not related to its normal content. High-definition computed tomography, MR imaging, and MR angiography allow diagnoses of IAC or cerebellopontine-angle cistern lesions, some of which could not be identified by older techniques.