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In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit changes in pressure of sound from the air to the ossicles inside the middle ear, and thence to the oval window in the ...
Whilst hearing loss is a common symptom in many diseases of the ear, for example in otosclerosis (abnormal bone growth in the ear), [3] the white, chalky patches on the tympanic membrane are fairly characteristic of tympanosclerosis. Cholesteatoma is similar in appearance but the whiteness is behind the tympanic membrane, rather than inside.
The vibratory portion of the tympanic membrane (eardrum) is many times the surface area of the footplate of the stapes (the third ossicular bone which attaches to the oval window); furthermore, the shape of the articulated ossicular chain is a complex lever, the long arm being the long process of the malleus, the fulcrum being the body of the ...
Otosclerosis is traditionally diagnosed by characteristic clinical findings, which include progressive conductive hearing loss, a normal tympanic membrane, and no evidence of middle ear inflammation. The cochlear promontory may have a faint pink tinge reflecting the vascularity of the lesion, referred to as the Schwartz sign. [citation needed]
The visible part is called the auricle, also known as the pinna, especially in other animals.It is composed of a thin plate of yellow elastic cartilage, covered with integument, and connected to the surrounding parts by ligaments and muscles; and to the commencement of the ear canal by fibrous tissue.
A normal tympanogram (left) is labelled Type A. There is a normal pressure in the middle ear with normal mobility of the eardrum and ossicles. Type B tympanogram may reveal (a) fluid in the middle ear, (b) perforation of the tympanic membrane or patent pressure equalization tube, or (c) a tumor in the middle ear.
Middle ear (ossicular chain), tympanic membrane, or external ear: Weber test: Sound localizes to normal ear Sound localizes to affected ear (ear with conductive loss) Rinne test: Positive Rinne; air conduction - bone conduction (both air and bone conduction are decreased equally, but the difference between them is unchanged).
The eardrum is an airtight membrane, and when sound waves arrive there, they cause it to vibrate following the waveform of the sound. Cerumen (ear wax) is produced by ceruminous and sebaceous glands in the skin of the human ear canal, protecting the ear canal and tympanic membrane from physical damage and microbial invasion. [5]