To understand tinnitus better, what causes it, and what can be done to stop ringing ears, it helps to know something about our hearing and how it works. This first article in a three part series introduces the basic anatomy of the outer ear, what it does, how it can go wrong to give rise to tinnitus, and how to get tinnitus help. The following two articles focus on the middle ear and the inner ear and tinnitus. With no further ado, let’s get a look at the outer ear.
Most of the time when we speak of ears we mean the outer ear, the part that is visible on either side of our heads, known as the pinna or auricle. Pinna or outer ears may be variously shaped and sized, but certain features are common to them all. They are made of cartilage with numerous curves and folds that serve to gather sounds and funnel them into the auditory canal. Before going further, let’s review the basic mechanism of sound.
Sound travels at about 740 miles per hour as air molecule vibrate in the form of pressure waves. Sound waves resemble the waves that spread on a pond’s surface after tossing a rock into the water. We hear the sound as the waves are gathered by the pinna, or outer ear, which funnels the sound through the auditory canal, and then the wave applies pressure against the ear drum. From there the sound energy travels through the middle and inner ear to the brain for processing. With that overview before us, let’s back up for more detail.
After the sound energy is gathered by the pinna, it is funneled through the auditory or ear canal. Only about 1 inch long and about 1/4 inch in diameter, the ear canal functions to funnel the sound collected by the pinna to the eardrum or tympanic membrane. According to the sound’s intensity, the pressure of the sound wave presses upon the eardrum. The auditory canal is cleverly shaped as a funnel to focus the wave vibrations. Funnel shaped for transmitting sound, the ear canal is also sloped to prevent water from gathering near the tympanic membrane under normal conditions. The form and dimensions of the auditory canal are just right for transmitting sound and for keeping outer ear infections to a minimum.
The external side of the tympanic membrane marks the innermost boundary of the outer ear. This ear drum is a thin, skin membrane that separates the outer ear from the middle ear. It is shaped like a flat cone, and it functions to transmit sound vibrations from the air to the ossicles of the middle ear. The tympanic membrane is extremely sensitive. The energy of the slightest detectable sound moves the ear drum only about 1 millionth of an inch. When you try to gain a mental picture of 1 millionth of an inch, you can begin to gain an appreciation for how truly wonderful our ears and hearing really are.
Cerumen or earwax is very important for the outer ear. Special wax glands produce cerumen for the ear canal. The purpose of cerumen is to lubricate and keep clean the interior part of the canal, and it helps to protect the canal from infection. As a cautionary note, cotton swabs and other implements should not be pushed into the auditory canals. Overly zealous use of cotton swabs is a known cause of impacted ear wax, and other implements can scratch or abrade the sensitive skin that lines the ear canal, making an opening for inflammation or infection. The best approach to earwax is to leave it alone as much as possible. Most of the time, for most people, earwax moves slowly toward the ear opening, carrying dirt and debris with it, keeping the ear canal clean.
There are times for some people, especially late in life, when cerumen fails to function properly. When that happens the ear canals may require cleaning from time to time, usually done best by a physician. But, for most of us, most of the time, only the outermost part of the canal needs cleaning. If cotton swabs or other implements are used, caution must be exercised.
At least two common causes of tinnitus can arise within the outer ears: impacted earwax and otitis externa, or inflammation or infection of the outer ear, sometimes referred to as swimmer’s ear. These two ringing in ears causes are readily identifiable and usually respond well to conventional tinnitus treatment.
