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Ears
By Orest Kornetsky
Ear Anatomy
Ear Physiology
• External Ear
– External auditory meatus funnels sound waves, which reflect off the
tympanic membrane to produce vibrations
– Cerumen (ear wax) protects the tympanic membrane from foreign
substances
• Middle ear
– Malleus, incus, and stapes and eustachian tube
– Function to:
• Conduct sound vibrations from tympanic membrane (outer ear) to cochlea
(inner ear)
• Protect the cochlea by reducing the amplitude of sounds
• Eustachian tube allows equalization of air pressure
• Inner ear
– Vestibule and semicircular canals
• Allow brain to sense body position and relation of angle of head to gravity
– Cochlea
• Transfers vibrations from stapes into nerve impulses
• The outer ear catches the waves of sound and funnels
them down the ear canal (about an inch long) and flush
up against the ear drum. The ear drum (tympanic
membrane) is the boundary between the outer ear and
the middle ear.
• In the middle ear, the malleus picks up the vibrations
from the eardrum, passes them to the incus which then
passes them to the stapes. The stapes terminates in a
tiny footplate that fits precisely into the contact point or
window of the inner ear.
• The window of the inner ear is the contact point of the
cochlea. The vibrations set up rolling waves in the
cochlear fluid which stimulate different areas of the
membrane, which rubs against specialized cells called
hair cells. This friction creates electrical impulses
transmitted by the cochlear nerve.
• CN VIII is responsible for signal transduction from
vestibule and cochlea to the brainstem. From brainstem,
a signal is sent to the cerebral cortex to interpret the
sound.
Hearing Loss
• Conductive
– Mechanical dysfunction of external or middle ear
– Partial hearing loss
– May be caused by impacted cerumen, foreign bodies,
perforated tympanic membrane, pus or serum in
middle ear, or otosclerosis (hardening of stapes)
– May be fixed
• Sensorineural
– Dysfunction of inner ear, CN VIII, or cerebral cortex
– Cannot be fixed
Developmental Considerations
•
•
Infants
– Greater risk for otitis media (middle ear infections) due to shorter
eustachian tube
Aging
– Cilia lining ear canal become coarse and stiff, impeding sound waves
– Cerumen more common
• Dry cerumen – gray and flaky. More common in Asians and Native
Americans
• Wet cerumen – brown and moist. More common in whites and
blacks
– Presbycusis - degenerative sensorineural hearing loss
– Auditory reaction time increases
Obtaining History
• Earaches? (otalgia)
– Location, character, intensity, associative and alleviating factors
– May be directly due to ear disease or maybe referred pain from a
problem in teeth or oropharynx
• A viral or bacterial upper respiratory infection may migrate up the
eustachian tube and involve the middle ear
• Infections?
– Frequency? Occurred in childhood?
• Discharge? (otorrhea)
– May suggest infection or perforated eardrum
– Typically with perforation, ear pain  drainage
• Otitis externa – purulent, sanguineous, or watery
• Acute otitis media with perforation – purulent discharge
More History
• Trouble hearing?
– Gradual our sudden?
• Presbycusis – gradual sensorineural hearing impairment in the
elderly
• Hearing loss due to trauma is often sudden
• Ringing in ears? (tinnitus)
– May be a result of medication
• Medications?
– Some are ototoxic
• Vertigo? (spinning)
– Subjective – person feels like he or she spins
– Objective – person feels like room spins
• Environmental noise
– Noise-induced hearing loss
Lesions of External Ear
Otitis Externa
Gouty Tophi
Assessing External Ear
• Size and Shape
– normal is 4-10cm tall
• Skin conditions
– Note edema, inflammation, lesions
• Tenderness
– Location?
• Pain in pinna indicates otitis externa
• Pain at mastoid process indicates mastoiditis or lymphadenitis
• External Auditory Meatus
–
–
–
–
Atresia – absence or closure of ear canal
Otitis externa may cause purulent discharge
Otitis media may cause rupture of tympanic membrane
If drainage present following trauma, possible basal skull
fracture. Perform glucose test (CSF (+) for glucose).
Inspecting Using Otoscope
• Pull the pinna up and
back in adult, straight
down in children under 3
years
• Hold otoscope upside
down and place dorsal
side of hand along
person’s cheek
• Insert speculum slowly
and avoid touching the
inner section of canal
wall, which is sensitive
and may cause pain.
Inspecting the External Canal
• Note any redness or
swelling, lesions, or
foreign bodies
• If discharge present,
note color and odor
Otitis
Externa
Inspecting the Tympanic Membrane
• Normal is shiny and
translucent
• Flat, slightly pulled in
at the center
– Valsalva maneuver
causes tympanic
membrane to flutter,
used to assess drum
mobility
Which tympanic membrane
is perforated?
Testing Hearing Acuity
• Voice test
– Whisper two syllable words
into one of the person’s
ears, while covering the
other one. Ask person to
repeat what you’ve said.
• Tuning fork tests
– Measure hearing by air
conduction or bone
conduction
– Weber test
– Rinne test
Weber Test
• Tuning fork is struck and
placed on head or
forehead, equal distance
from both ears
• Used to determine if
hearing loss is more
extensive in one ear than
the other
• This test cannot confirm
normal hearing, because
hearing defects affecting
both ears equally will
produce an apparently
normal test result
Rinne Test
• Compares air conduction and
bone conduction
• Place stem of vibrating fork on
mastoid process and ask when
sound goes away
• Quickly invert the fork so the
vibrating end is near the ear
canal. The person should still
hear a sound
• Normally the sound is heard
longer by air conduction rather
than bone conduction
– In conductive hearing loss,
sound heard longer by bone
conduction
Normal Hearing
Conductive Hearing Loss
Sensorineural Hearing Loss
Infants and Children
• Save otoscopic examination until the end
• May help to show otoscope to child and let
him or her play with it
• Stabilize (or ask a parent for help) the
child’s head in order to prevent movement
• Pull pinna straight down
• In infants, the tympanic membrane may
look thick and opaque after first few days
or after crying
• Tympanostomy tubes may be in place if
drainage occurs as a result of otitis media
Abnormalities in the Ear Canal
Acute Otitis
Media
Otitis Externa
Excessive Cerumen
Question 1
•
A nurse is performing a voice test to assess
hearing. Which of the following describes the
accurate procedure for performing this test?
1. Stand 4 feet away from the client to ensure that the
client can hear at this distance
2. Quietly whisper a statement and ask the client to
repeat it
3. Whisper a statement with the examiner’s back facing
the client
4. Whisper a statement while the client blocks both
ears
Question 2
•
A nurse is caring for a client who is
hearing impaired. Which of the following
approaches will facilitate
communication?
1.
2.
3.
4.
Speak frequently
Speak loudly
Speak directly into the impaired ear
Speak in a normal tone
Question 3
•
A client is diagnosed with a disorder
involving the inner ear. Which of the
following is the most common client
complaint associated with a disorder
involving this part of the ear?
1.
2.
3.
4.
Hearing loss
Pruritus
Tinnitus
Burning in the ear
Question 4
•
Which of the following statements made
by a parent should make the nurse
suspicious that the tympanic membrane
of a young child has ruptured?
1. “She has been crying all night, but she feels
better this morning.”
2. “She has some bloody, yellow-looking stuff
coming out of her ear.”
3. “My child does not seem to hear very well.”
4. “My child’s earwax is dark brown.”
Question 5
•
While examining the internal ear, the
nurse observes the light reflex on the
tympanic membrane. What does this
finding indicate?
1.
2.
3.
4.
Presence of pus
Fluid accumulation
Scar tissue
Normal finding