Ear Anatomy


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The auricle, or pinna, functions as a "collector" of sound waves. In animals, such as a fox, the collector function of the external ear is obvious. Sound waves are introducted into the ear canal, or meatus, where they are directed to the eardum.

Concha

The concha is the "shell-shaped" structure of the cavity of the external ear. 

Antitragus

The antitragus is the inferior margin of cartilage opposite the tragus.

Tragus

The tragus is the small epidermal fold just in front of the ear canal.

Aperture

The aperture opens into the ear canal.

Ear Canal

The adult ear canal is approximately 1.5 inches in length. The skin of the canal is only one cell in thickness, and, therefore is easy to damage, ulcerate, or abrade by use of Q tips, or other objects inserted into the canal. The final third of the canal is called the "bony" canal, and assists in accelerating the sound waves to the eardrum.

Helix Lock

The antihelix is the upper "wing" shaped crevice of the concha. Using this area is often important for proper retention of a hearing aid.

Hearing

The human ear is a marvel of complexity, and miniaturization. Whereas the outer, middle, and inner ear work syngergistically to transmit "sound" to the brain, the brain does not hear sounds. If fact, it can only "hear" electrical signals.

The outer, middle, and inner ears are all susceptible to a wide variety of pathology. Infections of the outer ear canal are called "external otitis," in general. Most are amenable to treatment. Some types of skin infections are difficult to resolve, ie fungal infections.

The middle ear contains the ossicles: the smallest bones in the human body. These bones act as a bridge from the eardrum to the oval window of the inner ear. There are very few pathologies associated with the ossicles. The primary one is "stapes fixation." Meaning, the stapes is fixed in place, and cannot vibrate. This condition is almost always "correctible" through surgery.

In children, and adults, fluid, or serum can accumulate in the middle ear cleft. This condition, otitis media, is unpleasant, and decreases hearing levels about 15-25%. Otitis media is treated by antibiotics, or, in many cases the fluid must be drained from the middle ear by a procedure called myringotomy.

The inner ear is the most well protected organ in the human body. It's position is roughly directly behind the eye. The inner ear is an encapsulated system of fluid filled chambers. This then, is the hydraulic part of the human ear. Sound from the middle ear is transformed into hydraulic oscillations. These vibratory patterns stimulate the outer, and inner hair cells, which trigger an electrical signal to the auditory cortex.

Damage to the hair cells, by any means, leads to sensorineural hearing loss, and is permanent in most cases.

Knowing how amazing our sense of hearing is, is it any wonder why an audiologist is dumbfounded that people expose their ears to jackhammers, chain saws, rock concerts, high reving engines, gunfire, et al...without even considering how much damage is being done to their ears, or the subsequent hearing loss that results from such abuse?