What are vestibular aqueducts?
Diagram of the inner ear. Vestibular aqueducts are narrow, bony canals that travel from the inner ear to deep inside the skull (see figure). The aqueducts begin inside the temporal bone, the part of the skull just above the ear. The temporal bone also contains two sensory organs that are part of the inner ear. These organs are the cochlea, which detects sound waves and turns them into nerve signals, and the vestibular labyrinth, which detects movement and gravity. These organs, together with the nerves that send their signals to the brain, work to create normal hearing and balance. Running through each vestibular aqueduct is a fluid-filled tube called the endolymphatic duct, which connects the inner ear to a balloon-shaped structure called the endolymphatic sac. A vestibular aqueduct is considered enlarged if it is greater than 1.5 millimeters in size, roughly the diameter of the head of a pin. If a vestibular aqueduct is enlarged, the endolymphatic duct and sac usually grow large too.
