Vestibular System: What is it? Structure, Anatomy and Functions

It is an integral part of the labyrinth found in the otic capsule in the petrous portion of the temporal bone in the ears.

This system is the one that provides the balance of the body, therefore if it is affected by any condition, it tends to affect the stability of the body, producing fainting or involuntary falls.

It consists of 5 different terminal organs, 3 semicircular channels that are sensitive to angular accelerations (head rotations) and 2 otoliths that are sensitive to accelerations.

The vestibular system is designed so that the body can do everything the brain commands by granting a sense of balance, from walking, running, climbing steps, to skateboarding, snowboarding and surfing, among other activities that merit balance and precision.


This system is a collection of structures in the inner ear that also provides an awareness of spatial orientation, that is, a sensation of whether the body is on its back or upside down.

The brain then integrates these data with other sensory information of the body to coordinate smooth and timely body movements, thus achieving the desired activity without suffering a faint or an unsuspecting fall for no apparent reason.

The general lines of its operation is a series of rather complex actions and not something that is acquired innately at birth.

Because all living beings that have the ability to have legs and feet or legs, learn to walk from small, then go refining and refining these interactive systems, and every time you learn something new that requires balance (such as walking by bicycle or paddleboard), the brain modifies and refines these integration processes even more.


According to the structure of the ear, it is possible to discern which parts of the ear are composed, mainly auditory in nature and which are part of the vestibular system.

The ear, also known as pinna, meaning “wing” or “fin”, is the funnel-shaped external ear that directs sound into the ear canal, also known as the external acoustic meatus, ‘meatus’ is in Latin’ channel ‘or’ passage ‘.

This passage carries sound to the tympanic membrane , or eardrum, which reverberates to transmit sound to the bones of the inner ear.

Within the tympanic cavity, there are three auditory ossicles, or bones, that collide against each other, transmitting sound waves that vibrate against the tympanic membrane to something called the oval window of the inner ear.

The oval window is the membranous connection point between the auditory ossicles and the fluid-filled structure of the inner ear, called the membranous labyrinth.

Half of the membranous labyrinth, the cochlea, is dedicated to convert sound waves into neuronal signals, while the other half, the vestibular system, is dedicated to deriving its sense of balance.

Both halves use the vestibulocochlear nerve, which transmits neuronal signals to the brain for interpretation and integration.


In the vestibular half of the inner ear, there are three semicircular canals, so called because of their semicircular shape, which run in three different orientations.

These orientations allow in the triangular vestibular system the orientation of the head and, consequently, the sense of balance, based on the three reference points of the channels.

The vestibular system does so through three sensory structures, called ampullary crests, which join the ends of the semicircular canals.

It also has sensory structures that line the ends of the semicircular canals and transmit signals to the vestibulocochlear nerve with respect to the rotation of the head.

Each of them is lined with a collection of small hair cells, named for the hair-like filaments, called stereocilia, which project from the top.

The stereocilia are embedded in a large gelatinous substance, called the dome, which, when pressed by the fluid on both sides, stimulates the stereocilia of the hair cells, which then conduct signals to the ventibulocochlear nerve.

In conclusion the ear not only works to listen, it has the vestibular system that has the task of giving balance to the body and if it is affected by an infection or an accident, dizziness or difficulties to walk correctly, because the The brain would not be receiving the necessary information to understand the relationship of the external environment with the body.