Quick Facts
The vestibular wall of cochlear duct is the thin anterior wall of the cochlear duct, which separates it from the scala vestibuli (Dorland, 2011).
Related parts of the anatomy
Structure and/or Key Feature(s)
The vestibular (or Reissner’s) membrane is an elastic membrane that serves as a barrier, separating the scala vestibuli and the cochlear duct in the cochlea. It is notably thinner than the basilar membrane, which is the other elastic membrane associated with the cochlear duct. The vestibular membrane extends obliquely in the cochlea. It is attached from the stria vascularis overlying the osseous spiral ligament to the spiral limbus overlying the osseous spiral lamina.
The vestibular membrane is comprised of two distinct layers, both comprised of squamous epithelia, separated by a basal lamina. Given its anatomical position, the vestibular membrane has surfaces facing the scala vestibuli and the cochlear duct. The surface associated with the perilymph of the scala vestibuli is lined by flat perilymphatic cells. These cells form tight junctions between themselves, and results in the formation of the diffusion barrier between the scala vestibuli and the cochlear duct. The surface associated with the endolymph of the cochlear duct is lined by a squamous epithelium. These epithelial cells also form tight junctions and have a role in ion transport (Standring, 2016).
Anatomical Relations
The vestibular membrane is interjacent between the scala vestibuli and the cochlear duct.
Function
The vestibular membrane serves as a barrier to separate the perilymph and endolymph located in the scala vestibuli and cochlear duct, respectively. While the perilymph and endolymph have a similar consistency, they differ in their ion concentrations. Perilymph has a high sodium content and a lower potassium content, while the opposite is true for the endolymph. The vestibular membrane serves as a diffusion barrier for ion exchange between these two fluids.
References
Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.
Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice., 41st edition. Elsevier Limited.
