By InnaKorda, MD, Institute of Nursing, TSMU Ears By InnaKorda, MD, Institute of Nursing, TSMU

Ear Anatomy

Ear Physiology External Ear Middle ear Inner 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 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 Sensorineural 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 Otosclerosis – decrease in mobility of oscicle

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) Infections? 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? Ringing in ears? (tinnitus) Medications? 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? Stand 4 feet away from the client to ensure that the client can hear at this distance Quietly whisper a statement and ask the client to repeat it Whisper a statement with the examiner’s back facing the client 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? 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? 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? “She has been crying all night, but she feels better this morning.” “She has some bloody, yellow-looking stuff coming out of her ear.” “My child does not seem to hear very well.” “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? Presence of pus Fluid accumulation Scar tissue Normal finding