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Tympanic membrane retraction describes a condition in which a part of the eardrum lies deeper within the ear than its normal position. The eardrum comprises two parts: the pars tensa, which is the main part of the eardrum, and the pars flaccida, which is a smaller part of the eardrum located above the pars tensa. Either or both of these parts ...
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 ...
Wittmaack's theory: Invagination of tympanic membrane from the attic or part of pars tensa in the form of retraction pockets lead to the formation of cholesteatoma. [12] Ruedi's theory: The basal cells of germinal layer of skin proliferate under the influence of infection and lay down keratinising squamous epithelium. [13]
He divided the membrane into two parts; the pars tensa (tense portion) and the pars flaccida (flaccid portion). In 1832 he published his findings in the London Medical Gazette in an article titled "On the form and structure of the membrana tympani". Today the flaccid portion of the tympanic membrane is known as "Shrapnell's membrane".
The tympanic reflex helps prevent damage to the inner ear by muffling the transmission of low frequency vibrations from the tympanic membrane to the oval window. The reflex has a response time of 40 milliseconds, not fast enough to protect the ear from sudden loud noises such as an explosion or gunshot.
Myringoplasty is the closure of the perforation of pars tensa of the tympanic membrane. [1] [2] [3] When myringoplasty is combined with removal of scar tissue, it is called tympanoplasty. The operation is performed with the patient supine and face turned to one side. The graft material most commonly used for the surgery is temporalis fascia.
In human anatomy, the pars flaccida of tympanic membrane or Shrapnell's membrane (also known as Rivinus' ligament) is the small, triangular, flaccid portion of the tympanic membrane, or eardrum. It lies above the malleolar folds attached directly to the petrous bone at the notch of Rivinus .
Prussak's space is important because it is a site for pars flaccida acquired cholesteatoma formation. [5] A cholesteatoma forms when there is a deep retraction pocket in the tympanic membrane. The lining of the tympanic membrane, which is skin, is shed, but if the membrane is retracted it gets trapped.