||The epithelium covering the surface of the tympanic membrane and external auditory canal possesses a unique self‑cleansing mechanism.
The outer, most superficial layers of corneocytes of the skin in this area desquamate by migrating radially off the surface of the tympanic membrane and then laterally along the bony canal to the outer cartilaginous canal where the superficial keratin is shed into the ceruminous material.
This mechanism accounts for the normal self‑cleansing action of the ear and can be observed by following, over a period of weeks, the path of the scab produced by a myringotomy incision.
One of the risks of using a cotton bud to clean the ear is that it just pushes wax and debris back into the ear.
The external ear is innervated by branches of several cranial nerves; the trigeminal (V), the facial (VII), the glossopharyngeal (IX) and the vagus (X), together with branches of the second and third cervical sensory roots.
With this diverse nerve supply, it is not surprising that many conditions affecting the upper food and air passages can present as pain referred to the ear.