Middle ear mucosa in newborn infants. A topographical and microanatomical study

The serially sectioned material comprised 38 temporal bones from 20 liveborns and stillborns with no signs of clinical otological disease. Columnar ciliated pseudostratified epithelium was found in all ears. It was most conspicuous in the Eustachian tube and around its orifice and throughout the hypotympanum. Besides, two other ciliated pathways were observed on the medial wall and on the roof. Squamous metaplasia was found in one case in both ears. Mucosubstances were scarce and no mucous glands were observed. Lamina propria was thicker and looser around the tubal orifice than elsewhere. Regression of the fetal loose connective tissue was evident towards the end of the gestation period.