THE VARIATIONAL ANATOMY OF THE EXTERNAL APERTURE OF THE HUMAN VESTIBULAR AQUEDUCT

A study was undertaken to demonstrate the variational anatomy of the e xternal aperture of the vestibular aqueduct in 90 human temporal bones obtained from 58 cadavers, Topographic landmarks of the posterior sur face of the petrous bone are useful for general orientation and includ e the external aperture of the vestibular aqueduct, internal auditory meatus, sigmoid sinus, subarcuate fossa, superior petrosal sinus and c ochlear canaliculus. We determined the mean distances from the externa l aperture of vestibular aqueduct to the above structures to be 10.98, 11.21, 9.42, 10.27 and 13.90 mm, respectively. Furthermore, the lengt h of the external aperture of the vestibular aqueduct revealed signifi cant differences between the right and left sides. The distances betwe en the EAVA and certain anatomical structures on the posterior surface of the temporal bone should be taken into consideration during surger y. Knowing the variability of the position of the external aperture of the vestibular aqueduct may help surgeons avoid traumatizing, and thu s producing inadvertent lesions to the hearing mechanism.