Figure 3: Scanning electron microscopy of the middle ear epithelium.

(a–c) Scanning electron microscopy (SEM) of the middle ear from an adult mouse (4 months old) near the orifice of the Eustachian tube, which is located outside the right bottom corner of the image (a). The region consists of mostly multi-ciliated cells (b), and is bordered by non-ciliated cells on the lateral wall of the tympanic or middle ear cavity (c). Scale bars: 20 μm (a), 4 μm (b,c). (d–f) SEM of the posterior dorsal roof regions of the middle ear cavity above the round window. Extensive ciliation was observed in the region (d–f). Scale bars: 167 μm (d), 4 μm (e), 4 μm (f). (g–i) The region lining the promontory of the cochlea, or the bulging of the medial wall of the tympanic cavity produced by the cochlea, which is medial and ventral to the dorsal roof of the middle ear cavity, is not ciliated and shares similarity to the non-ciliated region on the lateral wall of the tympanic cavity. The round window (RW) is posterior to the oval window (OW). The roof region dorsal to the round window is the region shown in (d–f). Scale bars: 333 μm (g), 20 μm (h), 4 μm (i).