Ear: Anatomy of Hearing and Balance (cont.)

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There is a small dense area of nerve fibers called the macule located in each of the saccule and utricle. The macule of the saccule is oriented vertically while the utricle macule is horizontal. Each macule consists of fine hair bundles which are covered by an otolithic membrane that is jelly-like and covered by a blanket of calcium crystals.

The calcium crystals are the structures that ultimately stimulate the position hairs and provoke nerve impulses created by the position changes and transmit that information to the brain stem and cerebellum.

Abnormalities of the vestibular system may cause:

  • vertigo (the sensation that the room is spinning);
  • benign paroxysmal positional vertigo;
  • labyrinthitis, and
  • Meniere's Disease.

Some examples of common diseases and conditions involving the ear include:

REFERENCE: Gray's Anatomy: The Anatomical Basis of Clinical Practice. Elsevier, Churchill, Livingstone. 39th Edition. 2004

Last Editorial Review: 4/15/2014