1/13/2024 0 Comments Labeling parts of the ear practice![]() The membrane situated in this cochlear window provides pressure compensation for mechanical waves traveling through the cochlea, and is the terminus of the scala tympani. Directly below the promontory is another small dark area which is the round window niche. It has eroded along with the incus.īelow and to the right of the promontory is another large depression leading to the opening of the Eustachian tube. In a normal ear, the stapes sits in the oval window, although the Stapes is not visible in this photograph. To the left of the promontory is a depression leading to the oval window. The wall bulging out in the center area is called the promontory, and is created by the basal turn of the cochlea. This surface, called the medial boundary or labyrinthine wall of the middle ear, is clearly seen in Figures 1 and 2. Figure 1:Ī normal eardrum (arrow is pointing to the pars flaccida).įigure 2 shows the view through the perforation, looking at the inner wall of the middle ear. The main portion of the eardrum almost seems separate from the pars flaccida. The bone around the pars flaccida has been eroded due to a long history of chronic infections and surgeries. ( Figure 1.) This is an attic retraction pocket with a possible cholesteatoma. ( Figure 3.) This zone is near the top and seen as a small white circle with red blood marking the center. Study the upper area of the eardrum-a normal eardrum-and note the arrow pointing to the pars flaccida. The pars tensa is the most familiar part of the drum to most practitioners. In a normal ear, the eardrum can be divided into the major portion, called pars tensa, which has an almost perfect round shape, and the uppermost portion of the eardrum called pars flaccida, which is a small, half-moon-shaped extension of the eardrum. The edges attach the tympanic annulus, and the center (the top of the cone) is formed at the end of the manubrium in the middle of the drum. A healthy, normal eardrum is cone-shaped. The third landmark, the umbo, is the point where the bottom end of the manubrium forms the center of the eardrum. Image of a perforated tympanic membrane that is not healed.
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