Figure 1.

Schematic drawing of the vestibular aqueduct and the endolymphatic duct and sac. The vestibular aqueduct is a bony canal located into the temporal bone (grey) and is delimited by its medial (internal) and external apertures. The endolymphatic duct and sac (blue) are membranous structures that lie within the vestibular aqueduct and comprise the sinus (1), the isthmus (2), a rugose (3), and a smooth portion (4). Black lines indicate the limits between the different portions of the endolymphatic duct and sac. Taken from [16], with permission from Springer International Publishing, 2017.