Cross-sectional area functions. Bony canal (black) and membranous duct (gray) cross-sectional area functions are shown each canal duct are shown for the HC (a), AC (b) and PC (c). Solid curves are for labyrinth 1 and dashed curves are for labyrinth 2. The membranous ducts are defined to extend from the cupula, along the canal, down the CC and/or utricle, and back to the cupula. Comparable membranous labyrinth measures by Igarashi23, Curthoys et al.12 and Curthoys et al.11 are designated by a solid circle, a solid square, and an asterisk, respectively. Also shown is an enlarged view of the labyrinth (d), which emphasizes the order of magnitude difference between the areas of the bony (white filled ellipses) and membranous canals (gray filled ellipses).