How the Ear Works

Outer Ear and Ear Canal
Sound vibrations travel through the air in waves to reach our ears. Large or small, these sound waves are first collected in the outer visible portion of the ear called the pinna and then funneled down through the ear canal to the eardrum.

Middle Ear

As the eardrum vibrates back and forth in time with the waves coming down the ear canal, it creates tiny corresponding motions that move along the three small bones of the middle ear collectively called the ossicles.

Inner Ear or Cochlea
The third and smallest bone of the ossicles, the stapes, is embedded in a membrane, called the oval window, which separates the middle ear from the inner ear or cochlea. The cochlea is a fluid-filled chamber containing thousands of hair-like nerve cells. The movement of the stapes at the oval window produces corresponding wave-like motions of the fluid in the cochlea. Each corresponding movement of the fluid causes the hair cells to bend, sending electrical impulses to the auditory nerve and on to the communication centers of the brain.

These hair cells are fragile and easily damaged. Once they are damaged, the hair cells will not fully recover, resulting in reduced sensitivity and hearing loss. As more and more hair cells are damaged, the hearing loss becomes more severe. Hearing loss resulting from hair-cell damage is known as sensory or “nerve” loss and is generally permanent.