How does the ear work? The ear works by receiving sound waves
and sending messages to the brain. The outer ear includes the
part of the ear you can see and the ear canal. The sound waves
go through the ear canal and hit the eardrum and cause it to
vibrate. The vibration of the eardrum causes the tiny bones in
the ear to move. This movement sends the sound waves to the
inner ear. What causes earaches? A tube called the eustachian
(say: "you-stay-shun") tube connects the middle ear with the
back of the nose. Normally this tube lets fluid drain out of the
middle ear. If bacteria or viruses infect the lining of your
child’s eustachian tube, the tube gets swollen and fills with
thick mucus. This keeps fluid in the ear from draining normally.
Bacteria can grow in the fluid, increasing pressure behind the
eardrum and causing pain. The eustachian tubes can become
blocked because of allergies, a cold or other infection. In
other cases, the adenoids (glands near the ear) become enlarged
and block the eustachian tubes.