The migratory capacity of the external auditory canal epithelium. A critical minireview.

The aim of the present paper was to review in detail and in an objective way, the most prominent data concerning the phenomenon of migration on the eardrum and deep on the bony part of the meatus. I present and discuss data obtained along different lines, in different species: e.g. ink dot migration, autoradiographic tracing, perforation studies, morphological and histological observations, tissue culture experiments, theoretical model studies, fetal and postnatal growth, immunohistochemical studies, probing molecular markers. Although the topic remains controversial, more and more it becomes clear that an active migration may occur deep in the stratified epithelia, and that a passive migration or keratin dispersion occurs additionally on the surface. The precise pattern along which the deep migration occurs, may differ in different species. In humans, the pars tensa more readily displays migration than the pars flaccida and the central area of the drum. Especially the inferior region of the annulus fulfils the criteria of a proliferation center stimulating active migration. The umbo region may represent the center of superficially radial dispersion.