According to the University of Wisconsin, the external auditory canal serves as a passageway for sound to reach the tympanic membrane, or eardrum; however, the external auditory canal also serves non-acoustic functions as well. The canal protects the eardrum from damage and maintains a clear passageway to the tympanic membrane through a self-cleaning process.
It is important for the ear canal to remain unobstructed so that sound waves can reach the eardrum easily. The University of Wisconsin explains that keeping the canal free of obstructions requires a process called epithelial migration. In most other skin-covered locations, incidental contact helps to remove dead skin cells; however, this does not work in the ear canal. Instead, the skin cells migrate laterally from the eardrum to the external opening. This is an important function as impacted material can compromise the efficacy of the ear.
Many of the protective functions of the ear canal arise from the anatomical structure of the ear. The University of Wisconsin states that the depth of the canal and the rigid walls that comprise it confer significant protection to the delicate eardrum at the canal’s terminus. Additionally, the ear produces wax and has an abundance of small hairs, which both help to protect the eardrum from injury.