Ear Disorders

Ears are the organs that help humans hear. The ears modify sound input, communicate it through the cartilaginous tissue and ear canals, and send signals through nerves, and into the brain. In addition, ears participate in body systems assisting with balance. Ear disorders have a variety of causes. The ear, or auricle, has three separate areas: the external ear, the middle ear, and the inner ear. An otoscope is the tool medical practioners use to examine the ear. Often a pneumatic bulb is used as well.

The outer part of the ear is made of cartilage. This part of the ear collects sound through the air. The sound is then transmitted into the external canal, through the middle ear, and to the inner ear where hair cells send signals through the nerves to the brain. The layers of the skin around the ear and the canal have thin hairs and, cerumen, or ear wax, is produced. Sometimes cerumen can completely occlude the external ear canal and dampen sound. External ears have been decorated for thousands of years. In some cultures, earlobes have stretched and enlarged to signify importance within the community. Other cultures have traditionally pierced earlobes for decorative jewelry. Occasionally, superficial infections of the skin on the ear can occur, sometimes due to these piercings or insect bites. Repeated injury to the cartilage sometimes does not allow the ear to heal correctly to its original shape; the normally soft and malleable cartilage becomes hard and lumpy. Thus, frequent trauma can distort the entire cartilage sometimes seen in “wrestler's ear” or “cauliflower ear.” Foreign bodies may become lodged in this location of the ear, as well. Additionally, the external canal of the ear can become infected, a condition known as “otitis externa” or “swimmer's ear.” This uncomfortable ailment is commonly treated with topical medications. Although rare, congenital external ear malformation can occur during embryologic development. Also, bony growths, called osteomas, may be in the external canal and uncommonly cysts and tumors will grow there. Anatomically, the external ear ends at the tympanic membrane, or eardrum.

The middle ear compartment begins behind the tympanic membrane. Sound is conducted through air in this compartment. The Eustachian tube connects the middle ear compartment to the posterior area of the pharynx. This tube helps to equalize pressure from the surrounding atmosphere to the middle ear cavity. Although the tube is normally closed, it opens up with swallowing and positive pressure. Increasing altitude in an airplane causes the air to expand and open the tube. However, upon descent, the volume of air shrinks [Page 574]and causes a vacuum in this closed system. Divers also experience this “Eustachian tube dysfunction” but for a different reason. In those cases, as divers go deeper, the external atmospheric pressure under water increases. This also causes a vacuum to occur. When the Eustachian tube is not working correctly, people will complain of a pressure sensation, or a popping and clicking sound in their ear. Active opening of the tube (by applying pressure to the nasal cavity) is sometimes necessary to open the Eustachian tube. An otoscope with the attached pneumatic bulb can help assess the movement of the tympanic membrane and assist with the examination of the middle ear and diagnosis. Sometimes, fluid can accumulate behind the ear drum. Clear, noninfected fluid is known as “serous otitis.”

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