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Eardrum
Medical expert of the article
Last reviewed: 07.07.2025
The eardrum (membrana tympani) is a thin, translucent, oval plate measuring 11 x 9 mm that separates the external auditory canal from the tympanic cavity (middle ear). The eardrum is attached at the end of the auditory canal, in the groove of the tympanic part of the temporal bone. The large lower part of the membrane is the stretched part (pars tensa), and the upper part, approximately 2 mm wide, adjacent to the squamous part of the temporal bone, is called the relaxed part (pars flaccida). In relation to the axis of the external auditory canal, the eardrum is located at an angle and forms an open angle of 45-55° with its lower wall. In the center of the membrane there is a depression - the navel of the eardrum (umbo mebranae tympani), corresponding to the attachment of the end of the malleus handle on its inner side. The eardrum consists of fibrous tissue, the fibers of which are oriented predominantly radially in the peripheral sections and circularly in the center. The eardrum is covered on the outside by the epidermis, which forms the cutaneous layer (stratum cutaneum), and on the side of the tympanic cavity by the mucous membrane - the mucous layer (stratum mucosum). In the unstretched part of the eardrum there is no fibrous layer and the cutaneous layer is directly adjacent to the mucous.
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