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Tinnitus Clarified

Encyclopedia category

Ear & auditory anatomy

8 headwords: 0 articles, 0 entries, 8 definitions

This category holds the parts of the ear and the hearing pathway that the rest of the encyclopedia keeps referring to: the outer ear and eardrum, the small bones and muscles of the middle ear, the fluid-filled inner ear and its hair cells, the auditory nerve, and the parts of the brainstem and cortex that process sound. Pages about causes and treatments name these structures constantly, and knowing what each one is and does makes those pages easier to follow.

Each headword here describes a structure, not a disease. Where a structure is involved in a condition, the page links to the page about that condition instead of repeating it, so you can read the anatomy first and then what can go wrong with it, or start from a diagnosis and come back here for the background.

The headwords are listed A to Z, each marked as a full article, a shorter encyclopedia entry or a glossary definition. Structures that go by more than one name appear under each name in the full index, which points to the one headword that covers them.

Every headword, A to Z

  • Auditory cortexDefinition

    The part of the brain that processes sound. Much current thinking holds that tinnitus arises from changes in how this region behaves after reduced input, rather than from a sound in the ear.

  • CochleaDefinition

    The spiral, fluid-filled structure in the inner ear that converts sound vibration into nerve signals. Most hearing loss associated with tinnitus involves damage here.

  • DehiscenceDefinition

    A gap or absence in a bony wall. In the ear it describes bone that should be covering something and is not — over a semicircular canal, or over the sigmoid sinus.

  • EndolymphDefinition

    The other inner-ear fluid, held inside the membranous labyrinth and separated from perilymph by a membrane. Distension of the endolymphatic space is called hydrops.

  • Eustachian tubeDefinition

    The passage connecting the middle ear to the back of the throat, which equalises pressure. When it does not open properly it can cause fullness, muffled hearing and tinnitus.

  • Hair cellsDefinition

    The sensory cells inside the cochlea that respond to sound. In humans they do not regenerate, which is why noise damage is permanent.

  • PerilymphDefinition

    One of the two fluids filling the inner ear, occupying the space around the membranous labyrinth. Finding it where it does not belong — in the air-filled middle ear — is what defines a perilymph fistula.

  • Sigmoid sinusDefinition

    A large vein carrying blood out of the skull, curving through the temporal bone directly behind the inner ear with only a thin plate of bone between them. When that plate is missing or the vein wall bulges, the turbulence becomes audible.

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