How the inner ear works may seem like a complicated process. While it is not the easiest process to understand without thorough knowledge of anatomy of the ear, here is a basic description of how hearing works.

Vibrations from sound against the eardrum travel through the middle ear to the inner ear. The middle ear delivers sound vibrations through a round window that leads to the inner ear. The part of the middle ear that sends the sound vibrations to the inner ear is called the stapes. The inner ear is filled with fluid. The vibrations from the stapes cause movement of this fluid.

The outside structure of the inner ear is called the bony labyrinth. The inner layer of the bony labyrinth is called the membranous labyrinth. The fluid-filled area just inside the inner ear is called the vestibule. The parts of the inner ear are connected to the vestibule. On one side of the vestibule is the semicircular canals. One the other side of the vestibule is the cochlea.

Sounds are translated into nerve messages in the cochlea. The cochlea is described as snail shell-shaped. Inside the membrane of the cochlea is the fluid-filled scala media. The receptor organ, called the Organ of Corti, is in the scala media. The auditory nerve, named the eighth nerve, connects to the base of the cochlea.

The Organ of Corti contains tiny hair cells. The outer hair cells have a supportive function and help regulate the tuning of the cochlea. The sensitive hair-like projections of the inner hair cells are called stereocilia. The movements of the stereocilia of inner hair cells reflect the vibrations of the sound. This movement is translated into nerve messages and passed to the auditory nerve.

The auditory nerve carries these signals to the brain where they are deciphered and comprehended by the individual. Proper hearing relies on how the inner ear works and the functioning of the auditory nerve. A malfunction of the inner ear or auditory nerve can cause sensorineural hearing loss. Sensorineural hearing loss is permanent hearing loss in that it cannot be medically repaired.