the inner
ear, consisting of the
vestibule,
cochlea, and
semicircular canals. The cochlea is concerned with
hearing and the vestibule and semicircular canals with the sense of
equilibrium. (See also color plates.) adj.,
adj labyrin´thine.
The bony portion of the labyrinth (
osseous labyrinth) is composed of a series of canals tunneled out of the temporal bone. Inside the osseous labyrinth is the
membranous labyrinth, which conforms to the general shape of the osseous labyrinth but is much smaller. A fluid called
perilymph fills the space (perilymphatic space) between the osseous and membranous labyrinths. Fluid inside the membranous labyrinth is called
endolymph. These fluids play an important role in the transmission of sound waves and the maintenance of body balance. The membranous labyrinth is divided into two parts: the
cochlear labyrinth, which includes the perilymphatic space and the cochlear duct, and the
vestibular labyrinth, which includes the
utricle,
saccule, and
semicircular canals.
Disorders of the inner ear, such as
labyrinthitis and
meniere's disease, are characterized by episodes of dizziness,
tinnitus, and
hearing loss.
ethmoid labyrinth (
ethmoidal labyrinth) either of the paired lateral masses of the
ethmoid bone, consisting of numerous thin-walled cellular cavities, the ethmoidal
cells.