5-9. DISORDERS OR MALFUNCTIONS OF THE EAR
a. Deafness. Deafness can be divided into two types. One type is caused by
the inability of the middle ear mechanisms to transmit sounds into the cochlea. This is
sometimes called conduction deafness. Another type, usually referred to as nerve
deafness, is caused by the impairment of the auditory nerve or cochlea. As one might
expect, if either the cochlea or auditory nerve is destroyed, the patient is permanently
deaf. However, if the cochlea and auditory nerve are still capable of functioning and
only the ossicular system has been destroyed, the patient can still hear because sound
waves can be conducted into the cochlea by bone conduction.
b. Tinnitus. Tinnitus is ringing in the ears or the sensation of noise in the ears
or head. Persons who take large doses of certain drugs (like aspirin) complain of
c. Meniere's Syndrome. Meniere's Syndrome is a disorder characterized by
intermittent attacks of vertigo (dizziness), nausea, vomiting, and profuse sweating. It is
a disorder of the membranous labyrinth of the inner ear.
Swimmer's Ear. Swimmer's ear is a fungal infection of the outer ear.
Otitis Media. Otitis media is the inflammation of the middle ear or eardrum.
Otitis Externa. Otitis externa is the inflammation of the outer ear.
Section III. ANATOMY AND PHYSIOLOGY OF EQUILIBRIUM (BALANCE)
a. Posture. Posture is the specific alignment of the body parts at any given
time. Humans can assume an infinite variety of postures. However, the truly erect
posture is unique to humans.
b. Equilibrium. Equilibrium is the state of balance of the body. An erect
standing human has a highly unstable equilibrium. Therefore, the human can easily fall.
Through a variety of sensory inputs (visual, and so forth) and postural reflexes, the body
is maintained in its erect posture.
c. Stimulus-Gravitational Forces. A primary sensory input for equilibrium
consists of gravitational forces. This input is received by the membranous labyrinth
within the internal ear. The gravitational forces are of two types: static, when the body
is standing still, and kinetic, when the body is moving in either linear (straight) or angular