The middle ear consists of the eardrum (tympanic membrane) and an air-filled chamber containing a chain of three bones (ossicles) that connect the eardrum to the inner ear (see Middle Ear Middle Ear The ear, which is the organ of hearing and balance, consists of the outer, middle, and inner ear. The outer, middle, and inner ear function together to convert sound waves into nerve impulses... read more ). The middle ear acts as an amplifier of sound, whereas the inner ear acts as a transducer, changing mechanical sound waves into an electrical signal that is sent to the brain via the nerve of hearing (statoacoustic nerve).
Middle and inner ear disorders cause many of the same symptoms, and a disorder of the middle ear may cause an inner ear disorder Overview of the Inner Ear The fluid-filled inner ear (labyrinth) is a complex structure consisting of two major parts: The organ of hearing (cochlea) The organ of balance (vestibular system) The cochlea and the vestibular... read more and vice versa.
Middle ear disorders may occur because of
Infection (such as acute otitis media Otitis Media (Acute) Acute otitis media is a bacterial or viral infection of the middle ear. Acute otitis media often occurs in people with a cold or allergies. The infected ear is painful. Doctors examine the eardrum... read more
, chronic suppurative otitis media Otitis Media (Chronic Suppurative) Chronic suppurative otitis media is a long-standing, persistently draining perforation of the eardrum (tympanic membrane). Acute otitis media and blockage of a eustachian tube are among the... read more 
, myringitis Myringitis Myringitis is a bacterial or viral infection of the eardrum. Myringitis is a form of acute otitis media and is caused by a variety of viruses and bacteria. The bacteria Streptococcus pneumoniae... read more , or mastoiditis Mastoiditis Mastoiditis is a bacterial infection in the mastoid process, which is the prominent bone behind the ear. Mastoiditis usually occurs when untreated or inadequately treated acute otitis media... read more )Blockage of the eustachian tube (which connects the middle ear and the back of the nose)
Injury (such as eardrum perforation Eardrum Perforation A perforation is a hole in the eardrum. Eardrum perforations are caused by middle ear infections and injuries. Perforation causes sudden ear pain, sometimes with bleeding from the ear, hearing... read more
, barotrauma Barotrauma of the Ear Barotrauma is an injury caused by increased air pressure, such as during airplane flights or scuba diving. Barotrauma can cause ear pain or damage to the eardrum. The eardrum separates the ear... read more , or objects in the ear Objects in the Ear Objects in the ear can be removed by flushing the ear canal with sterile water or saline or using suction, forceps, or other tools. If the foreign body cannot easily be removed, a referral to... read more )
Doctors usually base the diagnosis on people's symptoms and the physical examination. Doctors examine the ear canal and eardrum with an otoscope and often do hearing tests Testing Worldwide, about half a billion people (almost 8% of the world's population) have hearing loss. More than 15% of people in the United States have some degree of hearing loss that affects their... read more 
. Doctors also examine the nose and upper and middle parts of the throat for infections, allergies, and tumors.
A Look Inside the Ear
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