Anatomy

There are three distinct areas in the ear: the outer ear (pinna and external auditory meatus closed by the eardrum), the middle ear (eardrum case) and the inner ear (cochlea), from which the auditory nerve runs to the brain (figure 1 ).

The hammer, the first ossicle, is inserted into the eardrum. It is followed by the anvil and stirrup, whose base (platinum) is inserted into the oval window.

The cochlea (or snail) is a 30 mm-long bony tube that winds around an axis (columella). Its diameter varies from 10 mm at the base to 1 mm at the tip (apex). A bony blade (spiral) partially separates the tube into two ramps. Two membranes, the...