The semicircular canals are three tiny tubes located in the inner ear.
Their primary job is to regulate balance and sense head position.
Each one provides specific information about body position and balance.
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They help to ensure that your vision remains stable despite motion and activity.
Each semicircular canal has a specific structure, although it’s possible to have certain anatomical variations.
Structure
There are three round, hollow, semicircular canals.
Inside each of these tubes is a fluid calledendolymph.
This fluid stimulates hair cells inside a cluster of nerves called thecrista ampullaris.
Each semicircular canal starts and ends in thevestibule, a cavity in the inner ear.
Each one is angled on a specific plane.
These ducts are located in the temporal bones, paired bones at the sides and base of the skull.
They hang above the vestibule and the cochlea, the snail shell-shaped organ connected to it.
Function
The semicircular canals are primarily associated with sensing the rotational position of the head.
Due to inertia, fluid movement lags behind head movements.
This allows for smooth eye motion, resulting in stable vision despite head turns or twists.
The semicircular canals work alongside theotolithicorgans.
As part of the vestibular system, they help regulate balance in your body.
Each semicircular canal has a fluid called endolymph that stimulates hair cells in the tubes.
This sends signals to the brain that help sense your position and maintain stability.
Disorders in the semicircular canals can cause conditions like motion sickness, vertigo, and nystagmus.
Your healthcare provider can conduct tests of the vestibular system to evaluate function and balance.
2016;133(3):199-201. doi:10.1016/j.anorl.2015.09.002
Radiopaedia.Semicircular canal dehiscence.
Rabbitt R.Semicircular canal biomechanics in health and disease.J Neurophysiol.
2019;121(3):732-755. doi:10.1152/jn.00708.2018
Neuroscience Online.Vestibular system: structure and function.
Cedars-Sinai Hospital.Benign paroxysmal positional vertigo.
National Institute on Deafness and other Communication Disorders.What is Meniere’s disease?
2019;(146).
