Stratum corneum morphology in the human tympanic membrane and external auditory meatus

This report documents the spatial architecture of corneocytes in the human tympanic membrane and external auditory meatus. Using specimens of tympanic membrane and meatal skin dissected from fresh cadaveric temporal bones, the structure of the stratum corneum was investigated by the techniques of scanning electron microscopy and silver staining of epidermal sheets. An ordered vertical architecture was demonstrated in the skin obtained from both bony and cartilaginous portions of the auditory meatus, whereas the corneocytes of the tympanic membrane were randomly distributed. This orderly cellular configuration is a feature of the non-migratory skin of lower mammals, and some areas of human skin, but has not been previously reported to occur in the human external auditory meatus. The implication of these findings in terms of lateral epithelial migration is that in the external auditory meatus in order to maintain a vertically aligned structure the stratum corneum must move as one layer, being passively transported above the deeper epidermal layers in which migration occurs. In the tympanic membrane, however, net epithelial dispersion occurs by random insertion of new cells into a pavement-like layer of corneocytes.