Eardrum
Last reviewed: 23.04.2024
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The drum membrane (membrana tympani) is a thin translucent oval plate measuring 11x9 mm, separating the external auditory canal from the drum cavity (middle ear). The tympanic membrane is fixed at the end of the ear canal, in the groove of the drum part of the temporal bone. The large lower part of the membrane is a stretched part (pars tensa), and the upper part, approximately 2 mm in width, adjacent to the scaly part of the temporal bone, is called the not straightened part (pars flaccida). In relation to the axis of the external auditory canal, the tympanic membrane is located obliquely and forms with its lower wall an open angle of 45-55 ° to the outside. In the center of the membrane there is a deepening - umbo mebranae tympani, corresponding to the attachment of the end of the hammer handle from its inner side. The tympanic membrane consists of fibrous tissue, whose fibers in the peripheral regions are oriented mainly radially, and in the center - circularly. Outside, the tympanic membrane is covered with the epidermis, which forms the skin layer (stratum cutaneum), and on the side of the tympanic cavity - the mucous membrane - the mucous layer (stratum mucosum). In the not stretched part of the tympanic membrane there is no fibrous layer and the skin layer directly belongs to the mucous layer.
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