Centrifugal migration of the superficial keratinocyte layer of the tympanic membrane has been recognized for over a century.
This phenomenon can be readily demonstrated by painting dots of India ink upon the surface of the tympanic membrane.
There is a small area of the tympanic membrane, the slow zone, located anterior and inferior to the umbo where ink dots usually remain static for several weeks.
Once the ink dot moves from this area it travels peripherally at an increasing rate.
The larger central ink dots fragment into smaller sections as they migrate toward the periphery.
An ink dot applied to the umbo of this tympanic membrane remained stationary in the central slow zone after 1 week.