Scanning electron microscopic study on the distribution of epithelial cells in the Eustachian tube.

Canine Eustachian tube epithelium was examined by means of the scanning electron microscope. The part of the tube at the bone-cartilage junction was found to be the most active. It is here that goblet cells and large numbers of ciliated cells were found. Cilia were dense and covered by a mucus blanket. Near the tympanic end of the Eustachian tube, goblet cells were more numerous and ciliated cells less so. Near the pharyngeal end, goblet cells were numerous, while cilia were scanty and not uniform in length. Our findings support the concept that middle ear clearance is carried out by an active mucociliary mechanism as in other parts of the upper respiratory system.