Ear Ringing And The Middle Ear
To get a better grasp of tinnitus, how it comes about, and what can be done about it, it helps to understand something about how our sense of hearing works. This second part of a three article series explains the basics of the middle ear, how it functions, what can go wrong to precipitate tinnitus, and what can be done about it. The other two articles deal with tinnitus and the outer ear and the inner ear. Now, let’s look at the middle ear.
The tympanic membrane or ear drum marks the division between the outer ear and middle ear. The outside of the eardrum is part of the outer ear, while the inside of the eardrum is part of the middle ear.
As sound waves travel through the outer ear the energy quickly hits what we commonly call the ear drum. The ear drum constantly responds to changes in the air pressure surrounding us. When a sound wave moves through the ear canal and strikes the tympanic membrane, a chain reaction is set in motion, which is a purely mechanical reaction.
The eardrum, a taut and rigid piece of semi-transparent skin, moves back and forth to the pressure of the sound wave, vibrating with the energy according to pitch and volume and distance. The vibrations move quickly for the shorter waves of high-pitch sounds, and more slowly for the longer waves of low-pitch sounds. Loud sounds make a deeper impression on the ear drum, while the softest sounds detectable by humans move the eardrum only about 1 millionth of an inch. Truly a marvel!
The process that transforms sound waves into information that the brain interprets as the sounds we hear begins with the tympanic membrane. Under most circumstances, we receive energy from multiple sound waves at the same time. For instance, think about being in a restaurant having a conversation with a friend. The eardrum helps you to focus and concentrate on what your friend is saying, while putting all of the other sounds of the restaurant in the background.
Up to a certain point, the eardrum will also protect you from loud and harmful sounds. The tympanic muscle will actually contract in reaction to a very loud sound, and not vibrate in the normal way. The amount of sound energy that gets beyond the tympanic membrane is thereby reduced. Of course, that does not relieve us of our own responsibility to protect our ears from excessively loud sound.
The sound levels that we are often subjected to in our modern, industrial societies are relatively new on the evolutionary scale. Our ears are adapted to sound volumes that normally occur in nature itself, and have not had time to adapt to protect us from the loud volume levels often experienced in our modern world. Whether it is the screaming of jet engines at an airport, or the high decibel speakers of a night club, such loud sounds or noises are well-known as one of the primary causes of hearing loss and tinnitus today.
As remarkable as the protective mechanism of our ear drums might be, it can protect us from the sound volumes we experience in nature, not the volume and intensity of sound that we experience when standing 100 yards from a pile driver on a construction site. Therefore, we have responsibility for protecting our ears from the excessively loud sounds of today.
With that caution noted, let’s take the next step into the middle ear. So far we have tracked the journey of sound waves that are collected by the outer ear, channeled through the ear canal, and received by the ear drum that vibrates in response. The sound is then transferred to the mechanism of the middle ear which amplifies and focuses the sound energy, preparing it to be transferred to the inner ear which is fluid filled. In order to move through the denser medium of the fluid-filled inner ear, the sound really needs the kick of amplification provided by the middle ear. Just how the middle ear carries out that amplifying function can only magnify our appreciation for our sense of hearing.
The primary components within the usually dry chamber of the middle ear are called ossicles. Of all the bones found in the human body, the ossicles are the most tiny, and the word ossicle comes from the Latin root which means “tiny bone.” The sound vibrations of the eardrum are transferred directly to the malleus, the first of the three ossicles, which is attached directly to the eardrum. Then the malleus passes the energy on to the adjoining ossicle, the incus. The sound energy is then transferred to the stapes, the third ossicle. In turn, the stapes passes the energy on to the inner ear to which it is attached.
The middle ear is a mechanical wonder, and our sense of hearing is indeed a mechanical process, at variance with our senses of sight and taste which are chemical in nature. Our hearing is mechanical by nature.
The ossicles, working like levers, increase the mechanical power of the tympanic membrane, focusing the energy force from the larger membrane to the smaller oval window of the cochlea of the inner ear. The result is an amplification of the sound energy, because the ossicles, those three tiny bones, are perfectly designed to work together to pass on greater, more compacted energy to the cochlea of the inner ear. That leveraged amplification is necessary, as stated before, because when the vibrations are transmitted to the inner ear, they meet a much denser medium, the fluid filled cochlea. Is it not fantastic?
The eustachian tube, at the far end of the middle ear, connects the dry chamber of the middle ear with the nasopharynx or part of the throat. Anyone who has ever had a head cold knows that the ears, nose, and throat are all connected. The connection for the ear comes via the eustachian tube.
The primary purpose of the eustachian tube is to keep the air pressure equalized on both sides of the ear drum. It is also a drain tube for the middle ear, to keep it free from fluid or congestion. In so doing it is also there to keep the middle ear free from infection.
It is very common when you fly in an airplane or drive in the mountains to experience the feeling of different air pressure on either side of the eardrum. You may also have experienced a popping sound that produced a sense of relief by yawning or swallowing. That was the eustachian tube at work, equalizing the air pressure on either side of the tympanic membrane, assuring the proper functioning of the hearing mechanism.
When tinnitus arises within the middle ear, it is most commonly when the eustachian tube becomes stopped up from inflamed, swollen tissues due to sinusitis, rhinitis, or an allergy episode. When the eustachian tube becomes stopped up, fluids can be blocked within the middle ear providing a breeding medium for bacteria or viruses, which can result in otitis media or infection of the middle ear, which in turn can lead to tinnitus. While proper treatment of the infection and inflammation usually resolves the ringing in ears, chronic sinusitis or allergies can lead to chronic tinnitus. For such cases, holistic tinnitus treatment offers the best opportunity for a permanent tinnitus cure.