The retrosigmoid approach (RSA) is used in a wide variety of diseases in the cerebellopontine angle, and according to the findings, it can preserve hearing function during the resection of vestibular schwannomas. Complete exposure of the fundus of the internal auditory canal (IAC) could jeopardize the integrity of the otic capsule and subsequently cause profound hearing loss and chronic disabling vertigo. Great variability has been described in labyrinthine structures and to date there are no clear data on the distances of these structures to safely expose the IAC fundus.