Vestibulocochlear Nerve

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vestibulocochlear nerve

[və¦stib·yə·lə′käk·lē·ər ‚nərv]
(neuroscience)

Vestibulocochlear Nerve

 

in man, the eighth pair of cranial nerves.

The nerve copsists of two functional parts— the vestibular, which is the conductor of the impulses from the organ of equilibrium, and the cochlear, which perceives auditory stimuli. The vestibular part begins from the vestibular ganglion, which lies on the floor of the internal auditory canal. The peripheral processes of the nerve cells of that ganglion approach the receptor elements of the sacculus, utriculus, and ampulla of the membranous semicircular canals of the inner ear. The cochlear part originates from the spiral ganglion at the base of the bony plate of the cochlea. The peripheral processes of the cells of that ganglion enter into close contact with the receptor apparatus of the spiral organ (organ of Corti), which is located along the entire length of the cochlear canal of the membranous labyrinth. The central processes of the vestibular and spiral ganglia emerge from the inner ear and, as the corresponding parts of the nerve, are directed to the base of the brain. Outside the olivary nucleus of the medulla oblongata the central processes enter the base of the brain and, after uniting, reach their nuclei, which are localized in the corners of the rhomboid fossa.

With infectious or traumatic disorders of the fibers of the cochlear portion of the vestibulocochlear nerve, hearing disorders and even deafness may result. When there are disturbances of the vestibular portion, there is disruption of equilibrium and dizziness.

References in periodicals archive ?
The present study investigates the currently unproven hypotheses that there is no difference in cochlear nerve size between the two ears in normal-hearing adults.
We made the assumption that if the PTA score was normal and the clinical assessment and MRI were normal too, then the cause of the tinnitus was not organic ear disease and would not affect cochlear nerve diameter.
The facial nerve was identified as the anterosuperior nerve in the IAM and the cochlear nerve as the antero-inferior nerve (Figure 1, 2).
A thin-section, heavily T2 weighted image of the cochlea demonstrates fluid filled spaces of the cochlea (scala tympani and vestibuli), modiolus and cochlear nerve (Figure 1c).
Decision making about the amplification options may be difficult, particularly in patients with a hypoplastic cochlear nerve.
* Majority of CH patients have severe to profound hearing loss where a CI would be a reasonable option, if they have a cochlear nerve. During surgery, facial nerve malposition is to be expected due to associated semicircular abnormalities (particularly lateral SCC).
However, an anatomical study by Kuroki and Moller [sup][32] on cadaver specimens has demonstrated that the TL approach to the CPA offers a limited view; thus, it is necessary to medically retract the sigmoid sinus to obtain a medial view of the root entry zone of the cochlear nerve. In another anatomical investigation, Friedland and Wackym [sup][33] have demonstrated that the RS approach provides excellent visualization of the lateral recess of the fourth ventricle when a 30[degrees] endoscope is used, which provides a more direct appreciation of the implant site compared with the TL approach.
Hearing restoration with auditory brainstem implant in three children with cochlear nerve aplasia.
Meningiomas are the second most common lesion occurring at the CPA-IAC and can compress the cochlear nerve. These tumors demonstrate a broad-based dural attachment +/-a dural "tail" (Figure 13D).
Infection or inflammation of the cochlear nerve may produce SNHL.
In the ninth embryonic week, the cochlear windings are developed and the rise of neural epithelium builds a cochlear ganglion and neural fibers (early cochlear nerve) start to develop.
Masaki, "CT and MR imaging for pediatric cochlear implantation: emphasis on the relationship between the cochlear nerve canal and the cochlear nerve," Pediatric Radiology, vol.