The middle ear is the part of the ear which not only transmits sound but amplifies it as well.
The middle ear comprises the ear drum (or tympanic membrane) which vibrates when exposed to sound waves. The three small bones called Ossicles transmit the sound energy to the inner ear. During this process not only transmission of sound happens but amplification also occurs. The middle ear is an air containing compartment. The Eustachian tube which connects the middle ear with the nasal passage helps in this ventilation.
This sound conduction and amplification function can be impaired by the following conditions:
A) Fluid in the middle ear (Effusion): This happens when the Eustachian tube gets blocked due to various reasons.
B) Perforation of the tympanic membrane(due to infection).
C) Damage to the Ossicles can result in conductive hearing loss. The damage can be due to middle ear infection. The ossicles can get damaged due to injury as well ( as in head injury).
D) When the ossicle chain becomes fixed due to a condition called Otosclerosis. Otosclerosis is a bone remodelling disorder wherein the third ossicle called Stapes becomes fixed.
Damage to the Ossicles can result in conductive hearing loss. The damage can be due to middle ear infection.
Surgical procedures for correction of conductive loss include:
A) MYRINGOTOMY AND TUBE PLACEMENT:
In Myringotomy fluid from the middle ear is sucked out after making a clean incision on the ear drum. Through the incision the fluid is sucked out. A pressure equalizing tube called ‘GROMMET’ is placed to improve middle ear ventilation.
B) TYMPANOPLASTY:
It is a collective term to include reconstruction of middle ear hearing mechanism. The middle ear hearing mechanism may be damaged by middle ear infections (Chronic Otitis media). Non healing perforations are closed by grafting the ear drum. If there is damage to the ossicles they are reconstructed. These procedures are collectively called tympanoplasty.
C) STAPEDECTOMY:
It is a surgical procedure done for Otosclerosis. The ossicle called Stapes is removed and continuity of the conducting mechanism is restored by a PROSTHESIS.
