Dayton Ear, Nose
& Throat Surgeons, Inc.

John H. Boyles, M.D.         James J. Howard, M.D.         William E. Rogers, M.D.

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The Ear

Anatomy and Physiology of Hearing-The Ear and How it Works

The ear can be divided into three basic parts:

These three areas differ in structure as well as in how they individually function in order to work together to bring sound through our hearing mechanism.

Outer Ear

The Outer Ear consists of the external ear, the ear canal, and the first layer of the ear drum. The external ear (Pinna-Latin for “wing”) is the portion that is easily visible. It is flap like and funnel shaped. It acts to gather and direct sound waves into the ear canal. The ear canal (external auditory meatus) is open at the outer end which is surrounded by the external ear (pinna). It is “S” shaped and is sealed off at the inner end by the eardrum (tympanic membrane). The ear canal is like a pipe organ. The outer ear ends at the first layer of the eardrum.

Middle Ear

The middle ear begins at the second layer of the eardrum. The eardrum is concave, translucent and pinkish or pearl-grey in color. The eardrum absorbs the incoming sounds and passes the vibrations to the middle ear bones. There are three middle ear bones. Together they are called the ossicles. The middle ear bones, the hammer, anvil & stirrup (malleus, incus, stapes) are the smallest bones in the body. The middle ear transmits the vibrations from the eardrum to the cochlea of the inner ear.

Inner Ear

The cochlea is snail shaped and is set in the hardest bone of our bodies. It is no bigger than the tip of you little finger. The cochlea is fluid filled. It takes the vibrations from the middle ear bones and changes them to signals that can be passed on to our auditory nerve by hair cells that line the cochlea. The auditory nerve then takes those signals to our brain for processing. The cochlea can be compared to a piano with high frequencies at one end of the scale and low frequencies at the other end.