When people refer to the ear they may think of those structures that protrude off the side of their heads and serve to support eyeglasses and earrings. However, the ear is actually a much more complex structure that is divided into external, middle, and inner components.

 
The outer (or external) ear consists of that portion of the ear that protrudes off the side of the head together with a long tunnel, known as the external ear canal, that leads to the eardrum. The external ear serves to conduct sound to the middle ear. Wax is produced in the ear canal to protect the skin of the canal from infection and water damage.

The middle ear begins at the eardrum, which is a thin sheet like structure that completely seals the middle ear from the external ear. The middle ear must be filled with air to function properly.  The Eustachian tube connects the middle ear to the region of the adenoids at the back of the nose.  This tube maintains an air pocket in the middle ear.

Sound travels through the ear canal to the middle ear where three tiny bones vibrate, transmitting the sound to the inner ear.  These tiny bones called ossicles are shown in the diagram above; the malleus, incus and stapes.  Any interference with the vibration of these ossicles will impair sound transmission, causing a conductive (vibrational) hearing loss.  Some of the common causes of conductive hearing loss are: middle ear infection (otitis media), middle ear fluid (effusion), perforation of the eardrum, separation of the ossicles from chronic infection, and stiffening of the ossicles from scar tissue.  Excessive ear wax may cause a conductive hearing loss.  You may wish to temporarily provide a conductive hearing loss with ear plugs to protect the ears from damagingly loud sounds such as amplified music, machines or shooting.

The inner ear is the critical organ responsible for hearing.  It is the inner ear that converts sound into the electrical nerve impulse that is transmitted to the brain.  Essentially sounds differ by their loudness and pitch.  The complex details of loudness and pitch make up the various sounds in the world around us.  Inner ear damage causes nerve (or sensorineural) hearing loss.  This is more complex than conductive hearing loss as it may involve loss of the ability to discriminate pitch, and distortion of sound.  Sound distortion in the inner ear results in a decreased ability to understand words, even if the words are loud enough.  In this situation, speaking louder or even wearing a hearing aid cannot completely overcome the difficulty understanding speech.

From the inner ear nerve impulses carry the information to the brain along the auditory nerve.