| cochlear nuclei | The nucleus cochlearis dorsalis and nucleus cochlearis ventralis, located on the dorsal and lateral surface of the inferior cerebellar peduncle, in the floor of the lateral recess of the rhomboid fossa. They receive the incoming fibres of the cochlear part of the vestibulocochlear nerve and are the major source of origin of the lateral lemniscus or central auditory pathway. Synonym: cochlear nuclei, nuclei nervi cochlearis. (05 Mar 2000) |
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| cochlear nucleus | The brainstem nucleus that receives the central input from the cochlear nerve. The cochlear nucleus is located lateral and dorsolateral to the inferior cerebellar peduncles and is functionally divided into dorsal and ventral parts. It is tonotopically organised, performs the first stage of central auditory processing, and projects (directly or indirectly) to higher auditory areas including the superior olivary nuclei, the medial geniculi, the inferior colliculi, and the auditory cortex. (12 Dec 1998) |
| cochlear part of vestibulocochlear nerve | <anatomy, nerve> The cochlear part of the acoustic (8th cranial) nerve. The cochlear nerve fibres originate from neurons of the spiral ganglion and project peripherally to cochlear hair cells and centrally to the cochlear nuclei of the brainstem. They mediate the sense of hearing. (12 Dec 1998) |
| cochlear prosthesis | An electronic device implanted under the skin with electrodes in the middle ear on the promontory or cochlear window or in the inner ear in the cochlea to create sound sensation in total sensory deafness. A microphone behind the ear feeds sound waves into a microprocessor carried on the body, which analyzes the data and sends information back to a radio transmitter that triggers the electrodes in the middle or inner ear to produce the appropriate electrical pulses. This does not enable the patient actually to hear, but rather to distinguish different sounds according to the neural sensation they produce. The first successful cochlear implant was performed in 1978 in Melbourne, Australia. Such devices are among many implanted aids which have been made possible by the advent of microchip technology. Synonym: cochlear prosthesis. (05 Mar 2000) |
| cochlear recess | A small depression on the inner wall of the vestibule of the labyrinth at the portion of the pyramid of vestibule, between the two limbs into which the vestibular crest divides posteriorly; it is perforated by foramina giving passage to fibres which the cochlear branch of the vestibulocochlear nerve sends to the posterior extremity of the cochlear duct. Synonym: recessus cochlearis, Reichert's cochlear recess. (05 Mar 2000) |
| cochlear root of vestibulocochlear nerve | <anatomy, nerve> One of the components of the vestibulocochlear nerve; it is made up of the central processes of the bipolar neurons which compose the spiral (cochlear) ganglion in the spiral canal of the modiolus of the bony cochlea; the cochlear root enters the cranial cavity by passing in fascicles through the spiral foraminous tract at the bottom of the internal auditory meatus; it enters the brainstem through the pontomedullary groove, closely adhering to the caudoventral aspect of the vestibular root, and distributes its fibres to the ventral and dorsal cochlear nuclei in the floor of the lateral recess of the fourth ventricle. Synonym: radix cochlearis, cochlear root of vestibulocochlear nerve, inferior root of vestibulocochlear nerve, radix inferior nervi vestibulocochlearis. (05 Mar 2000) |
| cochlear root of VIII nerve | <anatomy, nerve> One of the components of the vestibulocochlear nerve; it is made up of the central processes of the bipolar neurons which compose the spiral (cochlear) ganglion in the spiral canal of the modiolus of the bony cochlea; the cochlear root enters the cranial cavity by passing in fascicles through the spiral foraminous tract at the bottom of the internal auditory meatus; it enters the brainstem through the pontomedullary groove, closely adhering to the caudoventral aspect of the vestibular root, and distributes its fibres to the ventral and dorsal cochlear nuclei in the floor of the lateral recess of the fourth ventricle. Synonym: radix cochlearis, cochlear root of vestibulocochlear nerve, inferior root of vestibulocochlear nerve, radix inferior nervi vestibulocochlearis. (05 Mar 2000) |
| cochlear window | An opening on the medial wall of the middle ear leading into the cochlea, closed in life by the secondary tympanic membrane. Synonym: cochlear window, fenestra of the cochlea, fenestra rotunda, round window. (05 Mar 2000) |
| crest of cochlear opening | The edge of the opening of the cochlear window to which the secondary tympanic membrane is attached. Synonym: crista fenestrae cochleae, crest of cochlear opening. (05 Mar 2000) |
| cupular caecum of the cochlear duct | The upper blind extremity of the cochlear duct. Synonym: caecum cupulare, cupular blind sac, lagena. (05 Mar 2000) |
| spiral cochlear ganglion | An elongated ganglion of bipolar sensory nerve cell bodies on the cochlear part of the vestibulocochlear nerve in the spiral canal of the modiolus; each ganglion cell gives rise to a peripheral process that passes between the layers of the bony spiral lamina to the organ of Corti, and a central axon that enters the hindbrain as a component of the inferior (cochlear) root of the eighth nerve. Synonym: ganglion spirale cochleae, auditory ganglion, cochlear ganglion, Corti's ganglion, spiral cochlear ganglion. (05 Mar 2000) |
| tectorial membrane of cochlear duct | A gelatinous membrane that overlies the spiral organ (Corti) in the inner ear. Synonym: membrana tectoria ductus cochlearis, Corti's membrane, tectorium. (05 Mar 2000) |
| tympanic wall of cochlear duct | The wall that separates the cochlear duct from the scala tympani; it consists of the osseous spiral lamina and the basilar membrane. Synonym: paries tympanicus ductus cochlearis, membrana spiralis, spiral membrane. (05 Mar 2000) |
| external wall of cochlear duct | The wall that faces the outer side of the cochlea. Synonym: paries externus ductus cochlearis. (05 Mar 2000) |
| little fossa of the cochlear window | A depression on the medial wall of the middle ear which has the fenestra cochleae (round window) in its lower portion. Synonym: fossula rotunda, little fossa of the cochlear window. (05 Mar 2000) |