Cell shape in the migratory epidermis of the external auditory canal

The shapes adopted by cells migrating within tissues and in cell cultures are related to both the direction and mechanism of migration. The skin on the tympanic membrane and deep external auditory canal is unique in its ability to migrate from the tympanic membrane to the junction between the deep and superficial parts of the ear canal, where it desquamates. Observations on 24 surface preparations of skin, obtained from 17 human temporal bones, revealed that the basal cells of the epidermis were spindle-shaped, and their long axes were aligned in the direction of migration. This cellular asymmetry and orientation did not persist in the more superficial layers of the epidermis. These findings are important in the consideration of the mechanism of migration, and the level within the epidermis at which it occurs.