Slide 49 (5x): Crista ampullaris, Helicotrema

    This section was taken through the apex of the cochlea near the helicotrema. Few bony elements of the modiolus are still present here, and thus the cochlear duct appears as a single tube containing a bilaterally symmetric organ of Corti. At the helicotrema the cochlear duct ultimately ends blindly, and the scala vestibuli becomes continuous with the scala tympani. In this image the scala tympani (arrow) and the scala vestibuli (SV) are both still present as separate structures. Note that the vestibular membrane now attaches at both ends to the spiral ligament rather than attaching to the ligament at one end and to the spiral limbus at the other.