Membranous labyrinth
The membranous labyrinth or endolymphatic labyrinth is the part of the inner ear housed in the osseous labyrinth. It comprises 3 distinct, but joined, sensory sacs and ducts supplied by the vestibulocochlear nerve (CN VIII):
- cochlear duct in the cochlea, responsible for hearing
- utricle and saccule in the vestibule, responsible for static balance
- semicircular ducts in the semicircular canals, responsible for kinetic balance
As the membranous labyrinth is slightly smaller than the osseous labyrinth, the two are separate by perilymph, which does not communicate with the endolymph contained in the membranous labyrinth.
Arterial supply
- vestibular and cochlear branches of the labyrinthine artery (from the basilar artery)
Innervation
The inferior vestibular branch of the vestibulocochlear nerve (CN VIII) supplies the saccule and posterior semicircular duct.
The superior vestibular branch of the CN VIII supplies the utricle, superior (anterior) and lateral (horizontal) semicircular ducts.
The cochlear branch of CN VIII supplies the cochlear duct.
Related pathology
