Deep within each ear there is a balanced system called the labyrinth
composed of three semicircular canals. These semicircular canals are also
connected to the cochlea which is the organ that allows for hearing. Each
semicircular canal is responsible for sensing a particular head direction. Each
semicircular canal is filled with fluid and when displacement of this fluid
occurs within the canal, nerve signals are sent to the brain informing which
direction the head just turned. The posterior semicircular canal shown here
detects when the head tilts down towards the shoulder. The superior
semicircular canal detects when the head nods up and down in a yes motion.
The lateral semicircular canal detects when the head shakes side to side in a no
When a person is dizzy, one of the main tests performed to determine whether the
inner ear is the source of the dizziness is the Dix Hallpike maneuver shown here.
The head is turned 45 degrees and the body laid back such that the head is
extended about 20 to 30 degrees. If the right inner ear is causing a person's
dizziness, eye twitching called nystagmus will occur; a condition called BPPV.
Depending on how the eye twitches, specific head maneuvers can be performed
to potentially cure a patient of their dizziness.