The outer ear consists of the visible part, called the pinna, which is composed of skin and cartilage, and the ear canal, the channel that leads to the eardrum. Behind the eardrum is the air-filled middle ear, which contains three tiny, delicate bones. The middle ear is directly linked to the respiratory system by the eustachian tube, the passage connecting the ear to the nose and throat.
This section covers disorders of the visible parts of the ear and of the ear canal, followed by conditions that affect the eardrum and middle ear. Outer- and middle-ear disorders have a number of causes, including injury, infections, obstruction, damage from atmospheric pressure changes, and inherited disease. The symptoms of these disorders include irritation, discomfort, pain, and, in some cases, partial hearing loss.
Most outer- and middle-ear problems are more easily treatable than those affecting the inner ear and are less likely to lead to permanent loss of hearing. Most causes of hearing loss are covered elsewhere (see Hearing and inner-ear disorders), as are disorders of the middle ear that particularly affect children (see Acute otitis media in children, and Chronic secretory otitis media).
For more information on the structure and the function of the ear, see Ears, Hearing, and Balance.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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