Table of ContentsView AllTable of ContentsAnatomyFunctionAssociated ConditionsTests
Table of ContentsView All
View All
Table of Contents
Anatomy
Function
Associated Conditions
Tests
The vestibule of the ear is best described as the area of theinner earbetween thetympanic cavityand posterior to thecochleathat contains the otolith organs. Lateral to the vestibule is the oval window and stapes footplate.
The vestibule of the ear and the otolith organs, called the utricle and saccule, are part of the vestibular system which controls ourequilibrium and balance. Diseases affecting this area of the middle ear typically result in vertigo.
Verywell / Laura Porter
The vestibule of the ear encompasses a portion of the inner ear roughly 4 millimeters (mm) in size. It is a bony cavity within the temporal bone that contains organs and nerves associated with the vestibular system. It is posterior to the cochlea and anterior to thesemicircular canals.
Otolith Organs
The utricle and the saccule are the two otolith organs that make up the vestibule. In both the utricle and the saccule, there is sensory epithelium (a type of tissue) and a macula, which is a receptor.
The utricle is located within the posterior part of the vestibule of the ear. The macula in the utricle is oriented in a horizontal position, which is important, as movement responds along the horizontal plane.
The saccule is the smaller of the two otolith organs. It lies anterior to the utricle. It is similar in composition to the utricle but the macula within the saccule is oriented vertically. This orientation makes the saccule sensitive to movement of the head along the sagittal (longitudinal) plane.
Macula
The macula contains sensory hair cell bundles which contain two types of hair-like structures:
Embedded within the otolithic membrane are specialized crystals called otoconia. The otoconia are made up of calcium carbonate. In particular, the otoliths function in two ways:
The vestibule’s primary purpose is related to your position in the world. Each part of the vestibule continuously sends a signal to your brain and changes in velocity or position either strengthens or weakens the signal sent. This in turn is translated in the brain into your sense of equilibrium.
The Utricle
The horizontal orientation of the utricle is important to how it functions. To understand this, imagine a sheet that divides the body between top (superior) and bottom (inferior). When you tilt you head while standing, your utricle is more likely to be driving your sense of balance compared to the saccule.
The tilting motion activates hair cell bundles in the macula of the utricle which strengthens the signal to the brainstem via the topmost (superior) portion of thevestibular nerve.
Unique to the utricle, sensory hair cells are slightly tipped toward the striola. The utricle also communicates with other parts of the inner ear. On one end, the utricle communicates with the semicircular canals, while on the opposite end the utriculosaccular duct allows communication with the other otolith organ, the saccule.
The Saccule
Also different in comparison to the utricle, in the saccule, the kinocilia are positioned further from the striola than the stereocilia. So bending in the opposite direction (away from the striola) causes increased signal strength to the brainstem. The saccule communicates with the cochlea via the ductus reuniens.
The Macula of the Utricle and Saccule
In relation to each striola (midline) the hair cell bundles are arranged in mirror-like fashion. When hair cells bend toward the kinocilium on one side of the striola, the bend away from the kinocilium on othe opposite side.
Bending towards the kinocilium strengthens the signal being sent to the brainstem (depolarization), while bending away from the kinocilium causes hyperpolarization of the receptor which decreases signal activity. Increasing or decreasing the signal strength changes your perception of balance and orientation.
Conditions that may occur in relation to the vestibules of your ear include disorders that can affect your sense of balance. Conditions may affect different parts of the vestibule and may include:
Other disorders not directly in relation to the vestibule, but closely related to the functionality of these otolithic organs include:
Many things can alter your sense of balance and identifying the root cause may involve several different types of testing following a thorough health history.
ENG and VNG
Electronystagmography (ENG) and videonystagmography (VNG) measure a series of eye movements to determine a level ofnystagmus. ENG is the most common test to begin differentiating causes of vertigo.
During ENG testing you will have electrodes placed to determine eye movement, whereas during VNG, you will wear googles with infrared sensors to measure eye movements.
Rotary Testing
Rotary testing using a similar strategy as ENG or VNG, employing the same electrodes, however you with either be instructed to rotate/tilt your head at certain intervals, or to sit in a chair that will rotate for you.
When in a chair that is rotating, you will be asked to wear a harness to secure your head to the chair’s headrest. You will be placed in a dark room for this test and will hear instructions over an intercom system.
VEMP
There are two types of vestibular evoked myogenic potential (VEMP) testing to evaluate for any lesions in the vestibule of the ear:
During either of these tests, you will wear headphones and have electrodes placed according to the VEMP test being performed. To evaluate for dysfunction in the utricle, electrodes will be placed on your face and measure muscle movement associated with sounds heard in the headphones.
Electrodes alternatively will be placed on your neck to measure muscle movement associate with any sounds to evaluate for dysfunction related to the saccule.
CDP
Computerized dynamic posturography (CDP) tests three different systems to evaluate any disorder of equilibrium. For this test, you will stand on a platform and be secured for safety in a harness.
You will follow directions related to a visual target and maintain balance on a shifting plate. This test evaluates sensory input from your vision, vestibular system, and muscles.
8 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Radiopaedia.Vestibule (ear).Hain TC.Anatomy of the otoliths. Chicago Dizziness and Hearing.Purves D, Augustine GJ, Fitzpatrick D, et al.Vestibular hair cells. Neuroscience. 2nd edition.Purves D, Augustine GJ, Fitzpatrick D, et al.The otolith organs: The utricle and sacculus. Neuroscience. 2nd edition.Kenhub.Vestibular system.Vestibular Diagnostic Association.Diagnostic tests for vestibular problems.Hain TC.Ocular vestibular evoked myogenic potential (oVEMP) testing. Chicago Dizziness and Hearing website.Hain, TC. Vestibular Evoked Myogenic Potential (VEMP) Testing - Cervical. Chicago Dizziness and Hearing website.https://www.dizziness-and-balance.com/testing/VEMP/vemp.html
8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Radiopaedia.Vestibule (ear).Hain TC.Anatomy of the otoliths. Chicago Dizziness and Hearing.Purves D, Augustine GJ, Fitzpatrick D, et al.Vestibular hair cells. Neuroscience. 2nd edition.Purves D, Augustine GJ, Fitzpatrick D, et al.The otolith organs: The utricle and sacculus. Neuroscience. 2nd edition.Kenhub.Vestibular system.Vestibular Diagnostic Association.Diagnostic tests for vestibular problems.Hain TC.Ocular vestibular evoked myogenic potential (oVEMP) testing. Chicago Dizziness and Hearing website.Hain, TC. Vestibular Evoked Myogenic Potential (VEMP) Testing - Cervical. Chicago Dizziness and Hearing website.https://www.dizziness-and-balance.com/testing/VEMP/vemp.html
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Radiopaedia.Vestibule (ear).Hain TC.Anatomy of the otoliths. Chicago Dizziness and Hearing.Purves D, Augustine GJ, Fitzpatrick D, et al.Vestibular hair cells. Neuroscience. 2nd edition.Purves D, Augustine GJ, Fitzpatrick D, et al.The otolith organs: The utricle and sacculus. Neuroscience. 2nd edition.Kenhub.Vestibular system.Vestibular Diagnostic Association.Diagnostic tests for vestibular problems.Hain TC.Ocular vestibular evoked myogenic potential (oVEMP) testing. Chicago Dizziness and Hearing website.Hain, TC. Vestibular Evoked Myogenic Potential (VEMP) Testing - Cervical. Chicago Dizziness and Hearing website.https://www.dizziness-and-balance.com/testing/VEMP/vemp.html
Radiopaedia.Vestibule (ear).
Hain TC.Anatomy of the otoliths. Chicago Dizziness and Hearing.
Purves D, Augustine GJ, Fitzpatrick D, et al.Vestibular hair cells. Neuroscience. 2nd edition.
Purves D, Augustine GJ, Fitzpatrick D, et al.The otolith organs: The utricle and sacculus. Neuroscience. 2nd edition.
Kenhub.Vestibular system.
Vestibular Diagnostic Association.Diagnostic tests for vestibular problems.
Hain TC.Ocular vestibular evoked myogenic potential (oVEMP) testing. Chicago Dizziness and Hearing website.
Hain, TC. Vestibular Evoked Myogenic Potential (VEMP) Testing - Cervical. Chicago Dizziness and Hearing website.https://www.dizziness-and-balance.com/testing/VEMP/vemp.html
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