Oval Window (Ear Location + Function)

The oval window can be found in the middle part along with three tiny bones, the incus, malleus, and stapes. The anvil, hammer, and stirrup are their more familiar names. The oval window plays a crucial role in hearing and works with those three bones to ensure sound is transmitted successfully. So, what is the oval window?

The oval window is an opening with a membrane covering that resides in the middle ear and helps transmit vibrations into traveling waves. The oval window links to a fluid-filled chamber. This chamber coils around, much like a snail’s shell, in a structure, called the cochlea.

The middle ear’s intricate geometry and small size are crucial for the transmission of sound. Without the oval window, the ossicular chain of the middle ear would not have a structure to vibrate. This means that the oval window is needed for sound waves to reach the cochlea. Here is all you should know about the oval window.

All About The Oval Window       

All parts of the ear each play their own role in either balance or hearing. The oval ear is one of the structures needed for sound to travel successfully from the outside environment to the cochlea. Here is more information about its location, function, and more.

The Location And Structure Of The Oval Window

The fenestra vestibuli, commonly known as the oval window, is an orifice with a membrane covering that links the middle ear directly to the inner ear’s vestibule. Three bones, including one of the smallest in the body, make up the middle ear and are attached to the structure of the oval window. These are the:

Hammer-shaped malleus that is affixed to the eardrum. The middle bone in the chain of bones is an anvil, also known as incus, and stirrup, also known as stapes, which is affixed to the membrane-covered orifice connecting the middle ear and the inner ear, the oval window.

The tympanic membrane, which divides the middle ear from the outer ear, is pounded by air vibrations. Because the malleus is attached to the tympanic membrane, it is disrupted when the membrane vibrates. The stapes hits another membrane known as the oval window, which divides the inner ear from the middle ear, and transmits the vibration of the malleus to the other bones. The inner ear’s fluid converts the stapes’ movement along the oval window into impulses. Furthermore, there is a bony labyrinth within the oval window.

What Role Does The Oval Window Play In Hearing?

In hearing, everything is dependent on vibration. So what role does the oval window play in the ear? To figure out what the role of the oval window is in the ears, the focus must be on the sound pathway up to the oval window. Essentially you want to find out how sound waves that enter the ear find a way to the cochlea, the organ of hearing. This way, the role of the oval window can be determined. The sound waves start on the external part of the ear, which is called the pinna. Soundwaves are caught by the pinna, and they enter the ear hole. 

In essence, sound is just vibrations moving through the air. These vibrations are concentrated in a small area by the outer ear, which includes the ear canal. The outer ear’s final point of contact is the eardrum, where the vibrations descend.

The transformation process starts right here. Similar to how drumsticks function when striking a drum, the eardrum vibrates as sound waves strike it. The eardrum is a highly thin membrane that covers the ear canal and prevents the middle ear from getting water-filled

There are three bones on the opposite side of the eardrum. These are the smallest bones in the human body. They are linked together. The malleus is a bone that is attached to the eardrum. As the eardrum moves, it forces the malleus and the incus to collide. The incus subsequently hits the stapes that rests on the oval window. The vibrational energy of the sound waves is transformed into mechanical energy by these bones. The middle ear is this entire area. It must be fluid-free. That’s because these bones won’t be able to move freely inside of this chamber if there is fluid.

The cochlea, situated in the inner ear, receives vibrations from the incus after being impacted by the malleus. The cochlea transmits information to the brain via the auditory nerve, converting the mechanical energy found in the middle ear into electrical energy.

The cochlea is shaped like the spiral of a snail, thus the name. The size of the gap inside the spiral determines how long the cilia, which are microscopic hairs inside the cochlea, grow. Each cilia length corresponds to particular sound frequencies. The brain can determine the frequency of the sound by observing when the incoming vibrational wave stops stimulating the cilia.

The three bones, known as the ossicles, make up the sole part of the middle ear. They serve to transmit eardrum vibrations to the oval window that divides the middle from the inner ear. The cochlea, which has hair cells floating in its own fluid, is located in the otic capsule.

The otic capsule has two windows for the purpose of hearing. One for sound to enter and one to exit. The oval window is the one where sound enters. The round window is the one through which sound exits. These are called windows since they are not fixed to a bone and allow sound to enter or exit. They are neither transparent nor open because the fluid would seep out if they were. Therefore, the oval window is necessary for the system to be elastic and vibrate.

The cochlea’s hair cells are connected to nerves that carry sound-related signals to your brain. As mentioned above, the ossicles, three little bones in the middle ear, transmit sound to the oval window. The purpose of these ossicles is to increase the sound energy that leaves the eardrum. They convert the sound into vibrations that can be felt at the oval window.

There is also some degree of amplification possible due to the huge eardrum and small oval window, similar to how the hydraulic system works. The oval window, which isolates the middle ear from the inner ear, is a crucial link in this network.

To put it simply, the middle ear is made up of three small bones called ossicles. they are connected in a chain across the middle ear from the tympanic membrane to the entrance of the cochlea, which is known as the oval window. The base of the stapes sits loosely in the cochlea’s oval window, held in place by the angular ligament. When the trio of bones depresses the oval window, it creates a wave that travels through the cochlea fluid. The waves then cause the structure called the basilar membrane to move as well.

Is The Oval Window The Same As The Round Window?

No, the oval window and the round window are not the same. Apart from the fact that the windows differ in size, they are also in different areas in the ear and have different functions. Sound waves do not even reach both windows at the same time, as the vibrations will be transmitted to the oval window by the ossicles. Oval windows are in the compression phase, while round windows are in the rarefaction phase. If they were in sync and in the same phase at once with one another, this would’ve led to them canceling each other out, and the sound wouldn’t be audible.

What Happens If There Are No Bones To Reach The Oval Window?

Understanding the components of the ear and just how sound travels from the ear to the brain might help one better comprehend hearing loss.

The oval window is moved due to the stapes’ rocking motion. As the oval window moves, a pressure wave propagates across the inner ear fluid. This wave causes the basilar membrane to sway up and down as it passes underneath.

You must go deeply into the anatomy to gain a deeper understanding. Scala tympani, scala vestibuli, and scala media are the segments of the cochlea. Perilymph is present in scala vestibule and tympani, while endolymph is present in scala media. The three bones merely transmit vibrations from the tympanic membrane to the oval window of the cochlea, which causes these fluids to move or vibrate in the cochlea. What if the person’s ears don’t have the three bones?

Some of the hearing is also attributable to bone conduction, which is the vibrating of the skull whenever we talk. However, the majority is because of the three bones. It would result in practically complete deafness if no bones cause the oval window to vibrate. The mechanics are the cause of that. The eardrum receives the sound, which is then sent to the brain. These sound waves are amplified in very small doses and transferred. The three bones’ alignment alone makes this possible.

This process or transduction cannot be done with only one bone. Deafness results from losing either one or the other. Without those bones, a person may be able to hear a muted version of their own voice. Still, they will be completely or almost completely deaf to other people’s voices and noises around them. They create the mechanical connection between the inner ear and the eardrum, the tympanic membrane. Without them, we wouldn’t be able to hear the majority of the sounds that we are bombarded with in our daily lives since they would bounce off the fluid in the head.

Hearing aids wouldn’t help someone missing these bones, but a cochlear implant that receives environmental sound and directly stimulates the cochlea of the inner ear would. Devices for middle ear conductive impairments, or what is known as sensorineural loss that restores hearing, are frequently mechanical in design, allowing for the study of such impairments using computational mechanical models.

The stapes transmit sound vibrations to the cochlea, the fluids in the inner ear. Ossicular chain discontinuity, a condition that has to do with the middle ear bones, can also be brought on by injury or infection. Some kids have middle ear bones that don’t effectively carry sound because of birth defects. Hearing rehabilitation calls for insulating the round window and adjusting the prosthesis’s impedance to that of the inner ear for individuals with a completely ruined middle ear audio conducting system but have a functioning inner ear.

Magnetically soft ferromagnetic particles are implanted under an oval window’s surrounding tissue. Magnetic forces bound a detachable elastic confusor with tiny permanent magnets onto the cochlea window. This confusor shields the round window while concentrating sound pressure just on the oval window.

Which Hearing Losses Affect The Function Of The Oval Window?

The area of a person’s hearing that is affected determines the sort of hearing loss that person suffers. The four categories of hearing loss are as follows:

  1. Conductive hearing loss has to do with the outer or middle ear that cannot adequately conduct sound.
  2. Sensorineural hearing loss is due to the cochlea’s hair cells either missing or damaged in this area.
  3. As the name states, mixed hearing loss is a conductive and sensorineural combination.
  4. Neural hearing loss concerns damage to the auditory nerve.

Although there are four hearing loss categories, only two truly apply to the oval window. One is conductive hearing loss. This kind of conductive hearing loss develops when the outer and middle ears cannot transmit sound. Soft noises could be difficult to hear in this situation, and harsher sounds might be muffled.

The other is mixed hearing loss. As mentioned above, conductive hearing loss may occasionally occur concurrently with sensorineural hearing loss. To put it another way, the inner ear or the nerve system to the brain may be damaged in addition to the outer or middle ear.

Conclusion

The external ear canal collects and transmits sound waves, which are then mechanically vibrated by the eardrum but also the ossicular chain before becoming traveling waves inside the fluid-filled cochlea, which is the inner ear. The bones are interconnected, with the malleus connecting to the tympanic membrane and the stapes connected to the oval window of the said cochlea. The oval window is an imperative part of the middle ear that enables vibrations to become traveling waves in the inner ear.

References

https://www.encyclopedia.com/medicine/anatomy-and-physiology/anatomy-and-physiology/oval-window

https://www.britannica.com/science/oval-window

https://www.hopkinsmedicine.org/health/conditions-and-diseases/hearing-loss/types-of-hearing-loss

Theodore T.

Theodore is a professional psychology educator with over 10 years of experience creating educational content on the internet. PracticalPsychology started as a helpful collection of psychological articles to help other students, which has expanded to a Youtube channel with over 2,000,000 subscribers and an online website with 500+ posts.