Cochlear hook anatomy: Evaluation of the spatial relationship of the basalcochlear duct to middle ear landmarks

The cochlear hook is an important anatomical area for the otologist perform ing cochlear implants and other otological procedures. who requires knowled ge of the basal cochlea. A total of 15 human temporal bones were dissected and the spatial relationship of the hook segment of the cochlear duct to th e stapes, round window, cochleariform process and ductus reuniens were eval uated. Inter-individual variability was noted for widths of scala tympani ( average width 1.36 +/- 0.25 mm) and scala vestibuli (average width 1.18 +/- 0.18 mm) in the region of typical cochlear implant placement, with the sca la vestibuli occasionally being wider than the scala tympani. Thr cochlear duct was in closest proximity to the stapes at the midportion of the footpl ate, with an average distance of 1.23 mm at this narrowest width. A fibrous anchor, not previously described in otology literature. was identified sec uring the must basal end of the cochlear duct. Knowing the spatial relation ship of the cochlear duct to the middle and inner ear structures could prev ent damage to the basilar membrane in procedures around or involving the ba sal cochlear, such as cochlear implantation, stapedotomy, or implantable he aring devices.