Lecture Notes

Assessing the Ears

purposes
1. to determine changes in the internal environment of the body
2. to yield valuable information on general health status
3. to provide information needed to identify specific systemic diseases
4. to determine the health status of the special sense organ for hearing and balance
stucture and function
1. function
  1. special sense organ for hearing and balance
2. structure
  1. external ear
    1. funnels sound waves into the external auditory canal
    2. composed of the auricle or pinna and external auditory canal
      1. auricle or pinna
        
        composed of elastic cartilage and skin
        composed of the following parts:
        
        helix
        antihelix
        external auditory meatus
        tragus
        antitragus
        lobule
      2. external auditory canal
        
        shape
        
        straight in infants and young children
        slight S-curve in the adult
        
        outer third is composed of cartilage
        
        within the cartilaginous portion are the following:
        
        hair follicles
        pilosebaceous glands
        ceruminous, or wax-producing, glands
        
        inner two thirds are composed of bone
  2. middle ear
    1. tiny, air-filled cavity inside the temporal bone which has three functions:
      1. conducts vibrations from the outer ear to the central hearing apparatus in the inner ear
      2. protects the inner ear by reducing the amplitude of loud sounds
      3. equalizes air pressure on each side of the tympanic membrane (TM) so that the TM does not rupture
    2. composed of the TM, ossicles, and eustachian tube
      1. TM
        
        pearly gray, translucent membrane that separates the external and middle ear and is tilted obliquely in the external auditory ear canal
        composed of the pars flaccidia, pars tensa, short process of the malleus, handle of the malleus, umbo, and cone of light
        
        pars flaccidia
        
        upper, smaller portion of the TM
        
        pars tensa
        
        the remaining portion of the TM
        
        short process of the malleus
        
        upper end of the malleus which appears as a tiny knob
        directly attached to the TM
        
        handle of the malleus (manubrium)
        
        middle of the malleus, which extends downward from the short process to the umbo, or tip
        divides the pars tensa into the anterior and posterior folds
        
        umbo
        
        lower end of the malleus
        
        cone of light
        
        reflection of the otoscope light
      2. ossicles
        
        malleus
        incus
        stapes
      3. oval window
      4. round window
      5. eustachian tube
        
        connects the nasopharynx with the middle ear
        provides an air passage from the nasopharynx to the ear to equalize pressure on both sides of the tympanic membrane
        is normally closed, but opens during swallowing and yawning
  3. inner ear
    1. end-organ for hearing and balance
    2. situated in the petrous portion of the temporal bone of the skull
    3. composed of the semicircular canals, vestibule, and cochlea
      1. semicircular canals
        
        end-organ of balance
        the three semicircular canals are directed posteriorly, superiorly, and horizontally
        ampulla
        
        dilated end of each semicircular canal
      2. vestibule
        
        entraceway to the inner ear
      3. cochlea
        
        end-organ of hearing
        snail-shaped structure composed of 2 3/4 turns
        contains fluids called endolymph and perilymph
        contains the organ or Corti and transmits stimuli to the cochlear branch of the CN VIII (Auditory)
3. pathways of hearing
  1. air conduction
    1. describes the typical pathway of hearing
    2. the most efficient method of hearing
    3. involves the:
      1. external, middle, and inner ear
      2. conductive and sensorineural phases of hearing
      3. occurs in the following manner:
        
        sound waves enter the external auditory canal and strike the TM, causing it to vibrate
        vibrations of the TM are transmitted to the auditory ossicles of the middle ear, causing them to vibrate
        vibrations of the ossicles of the middle ear cause an inward motion of the footplate of the stapes, which deforms the oval window
        deforming of the oval window cause waves in the perilymphatic fluid of the inner ear
        waves in the perilymphatic fluid of the inner ear are transmitted to the endolymphatic fluid of the inner ear, causing waves in the endolymphatic fluid of the inner ear
        waves in the enodymphatic fluid of the inner ear causes distortion of the hairs cells of the organ of Corti
        distortion of the hair cells of the organ of Corti causes them to convert the mechanical force into an electrochemical signal that is propagated down the acoustic nerve to the temporal cortex of the brain where the appreciation of the sound occurs
    4. loss of the ability to hear through air conduction is is indicative of a conductive hearing loss
    5. sypmtoms of conductive hearing loss:
      1. distortion of sounds that impairs the understanding of words
        
        relatively minor
      2. effects of a noisy environment
        
        hearing may seem to improve
      3. patient's own voice
        
        tends to be soft
      4. usual age of onset
        
        most often in childhood and young adulthood, up to age 40
      5. ear canal and tympanic membrane
        
        there is a visible abnormality, except in otosclerosis
      6. causes
        
        obstruction of the external auditory canal
        otitis media
        perforated or relatively immobilized tympanic membrane
        otosclerosis (fixation of the ossicles by bony overgrowth)
  2. bone conduction
    1. describes an alternative pathway of hearing
    2. the least efficient method of hearing; used for testing purposes
    3. involves the:
      1. inner ear only, bypassing the middle and inner ear
      2. sensorineural phase of hearing only, bypassing the conductive phase of hearing
    4. loss of the ability to hear through bone conduction is indicative of a sensorineural hearing loss
    5. symptoms of sensorineural hearing loss
      1. distortion of sounds that impairs the understanding of words
        
        often present as the upper tones of words are disproportionately lost
      2. effects of a noisy environment
        
        hearing may seem to worsen
      3. patient's own voice
        
        tends to be loud
      4. usual age of onset
        
        most often in the middle or later years
      5. ear canal and tympanic membrane
        
        the problem is not visible
      6. causes
        
        sustained exposure to loud noises
        drugs
        infections of the inner ear
        trauma
        tumors
        congenital and hereditary disorders
        aging process (presbycusis)
  3. two types
    1. sounds waves
pertinent history
1. adults
  1. earache
  2. ear infections
  3. discharge
  4. hearing loss
  5. environmental noise
  6. tinnitus
  7. vertigo
  8. self-care behaviors
  9. usual state of health
2. additional history for infants and children
  1. ear infections
  2. ability of the child to hear
3. additional history for the aging adult
  1. if neck pain is a problem, the effect on daily activities
preparation of the patient and environment
1. patient
  1. greet the patient and establish rapport
  2. explain the procedure to the patient in simple terms what will be done, what he/she should expect, and how he/she can cooperate during the examination
  3. assist the patient in assuming a position of sitting up straight with his/her head at eye level
  4. encourage the patient to ask questions and mention any discomfort he/she feels during the examination
2. environment
  1. private
  2. adequately lit
  3. warm
  4. quiet
techniques of examination
1. inspect the auricles
  1. observe the patient's auricles from all angles. by:
    1. standing at the right side of the patient
    2. observing the patient's right auricle from all angles
    3. standing at the left side of the patient
    4. observing the patient's left auricle from all angles
  2. normal findings:
    1. top of the auricle positioned level with the outer corner of the eye
    2. 4 - 10 centimeters in length
    3. slanted 10 degrees of vertical toward the occiput
    4. skin intact, consistent with genetic background, smooth, and uniform
  3. deviations from normal findings:
    1. top of the auricle positioned below the outer corner of the eye
      1. e.g., mental retardation
    2. less than 4 centimeters in length
      1. e.g., microtia
    3. greater than 10 centimeters in length
      1. e.g., macrotia
    4. slanted greater than 10 degrees toward the occiput
      1. e.g., mental retardation
    5. redness
    6. lesions
    7. edema
    8. lumps
    9. nodules
    10. crusts
    11. scaliness
2. palpate the helix, tragus, and mastoid process of the auricles
  1. palpate the helix, tragus, and mastoid process of the auricles, by:
    1. standing at the right side of the patient
    2. grasping the helix of the patient's right auricle with the thumb and index finger of your left hand and moving it up and down while asking the patient if the maneuver elicts any tenderness
    3. pressing firmly on the tragus of the patient's right auricle with the index finger of your left hand whilte asking the patient if the maneuver elicits any tenderness
    4. pressing firmly on the mastoid process behind the patient's right auricle with the index finger of your left hand while asking the patient if the maneuver elicits any tenderness
    5. standing at the left side of the patient
    6. grasping the helix of the patient's left auricle with the thumb and index finger of your right hand and moving it up and down while asking the patient if the maneuver elicts any tenderness
    7. pressing firmly on the tragus of the patient's left auricle with the index finger of your right hand whilte asking the patient if the maneuver elicits any tenderness
    8. pressing firmly on the mastoid process behind the patient's left auricle with the index finger of your right hand while asking the patient if the maneuver elicits any tenderness
  2. normal findings:
    1. absence of tenderness upon movement of the helix up and down
    2. absence of tenderness upon palpation of the tragus and mastoid process
  3. deviations from normal findings:
    1. presence of tenderness upon movement of the helix up and down
      1. e.g., otitis externa, furnucle
    2. presence of tenderness upon palpation of the tragus
      1. e.g., otitis externa, furnucle
    3. presence of tenderness upon palpation of the mastoid process
      1. e.g., mastoiditis, lymphadenopathy of the posterior auricular lymph nodes
3. inspect the external auditory meatus of the patient's auricles
  1. observe the external auditory meatus of the patient's auricles from all angles, by:
    1. standing at the right side of the patient
    2. observing the patient's right external auditory meatus from all angles
    3. standing at the left side of the patient
    4. observing the patient's left external auditory meatus from all angles
  2. normal findings:
    1. pink, smooth, and uniform
    2. absence of obstruction
    3. absence of discharge
    4. absence of foreign body(s)
  3. deviations from normal findings:
    1. redness
    2. lesions
    3. edema
    4. lumps
    5. nodules
    6. crusts
    7. scaliness
    8. presence of obstruction
    9. presence of discharge
    10. presence of foreign body(s)
4. inspect the external auditory canal
  1. inspect the external auditory canal, by:
    1. gathering an otoscope
    2. attaching and securing the head of the otoscope to its handle
    3. attaching the largest size speculum to the head of the otoscope that fits comfortably into the patient's external auditory canals
    4. switching on the otoscope
    5. standing at the right side of the patient
    6. holding the otoscope between the thumb and index finger of the right hand with the handle of the otoscope facing up
    7. asking the patient to tilt his/her head toward his/her left shoulder
    8. grasping the helix of the patient's right auricle firmly with the thumb and index finger of the left hand and gently pulling it up and back
    9. bracing the dorsal (back) surface of the right hand against the right side of the patient's face to stabilize the otosocpe as it is inserted into the external auditory canal of his/her right auricle
    10. inserting the speculum gently and slightly downward and forward into the external audtiory canal of the patient's right auricle
    11. standing at the left side of the patient
    12. holding the otoscope between the thumb and index finger of the left hand with the handle of the otoscope facing up
    13. asking the patient to tilt his/her head toward his/her right shoulder
    14. grasping the helix of the patient's left auricle firmly with the thumb and index finger of the left hand and gently pulling it up and back
    15. bracing the dorsal (back) surface of the left hand against the left side of the patient's face to stabilize the otoscope as it is inserted into the external auditory canal of his/her left auricle
    16. inserting the speculum gently and slightly downward and forward into the external auditory canal of the patient's left auricle
  2. normal findings:
    1. pink, smooth, and uniform
    2. absence of obstruction
    3. absence of discharge
    4. presence of honey-colored, dark brown, or black and moist cerumen in Caucasians and African-Americans
    5. presence of gray and dry cerumen in Asians and Native-Americans
    6. absence of foreign body(s)
  3. deviations from normal findings:
    1. redness, edema
      1. e.g., otits externa
    2. lesions
    3. lumps
    4. nodules
    5. crusts
    6. scaliness
    7. presence of obstruction
    8. presence of bloody or clear, watery discharge that is oily feeling and glucose postive after trauma
      1. e.g., basilar skull fracture
    9. presence of purulent discharge
      1. e.g., otitis media if the tympanic membrane has ruptured
    10. impacated cerumen
    11. presence of foreign body(s)
5. inspect the tympanic membrane
  1. inspect the tympanic membrane, by:
    1. gathering an otoscope
    2. attaching and securing the head of the otoscope to its handle
    3. attaching the largest size speculum to the head of the otoscope that fits comfortably into the patient's external auditory canals
    4. switching on the otoscope
    5. standing at the right side of the patient
    6. holding the otoscope between the thumb and index finger of the right hand with the handle of the otoscope facing up
    7. asking the patient to tilt his/her head toward his/her left shoulder
    8. grasping the helix of the patient's right auricle firmly with the thumb and index finger of the left hand and gently pulling it up and back
    9. bracing the dorsal (back) surface of the right hand against the right side of the patient's face to stabilize the otoscope as it is inserted into the external auditory canal of his/her right auricle
    10. inserting the speculum gently and slightly downward and forward into the external audtiory canal of the patient's right auricle
    11. standing at the left side of the patient
    12. holding the otoscope between the thumb and index finger of the left hand with the handle of the otoscope facing up
    13. asking the patient to tilt his/her head toward his/her right shoulder
    14. grasping the helix of the patient's left auricle firmly with the thumb and index finger of the left hand and gently pulling it up and back
    15. bracing the dorsal (back) surface of the left hand against the left side of the patient's face to stabilize the otoscope as it is inserted into the external auditory canal of his/her left auricle
    16. inserting the speculum gently and slightly downward and forward into the external auditory canal of the patient's left auricle
  2. normal findings:
    1. pearly gray
    2. shiny
    3. translucent
    4. intact
    5. cone of light prominent in the anteroinferior quadrant
      1. at 5:00 in the right ear
      2. at 7:00 in the left ear
    6. umbo, handle of the malleus, and short process of the malleus clearly visible
    7. bulges slightly when the patient holds his/her nose and swallows
  3. deviations from normal findings:
    1. dull
    2. blue or dark red
      1. e.g., indicates blood behind the tympanic membrane (hemotympanium) and possible trauma or skull fracture
    3. bright red
      1. e.g., indicates infection in the middle ear and possible acute purulent otitis media
    4. yellow/amber
      1. e.g., indicates serous fluid behind the tympanic membrane and possible serous otitis media
    5. air/fluid level
      1. e.g., indicates serous fluid behind the tympanic membrane and possible serous otitis media
    6. absent or distorted light reflex
      1. e.g., indicates bulging of the eardrum and possible acute otitis media
    7. dark, oval areas
      1. e.g., indicates perforation and possible rupture of the tympanic membrane
    8. white, dense areas
      1. e.g., indicates scarring and the sequelae of infections
    9. accentuated landmarks
      1. e.g., indicates retraction of the tympanic membrane and possible negative pressure in the middle ear from an obstructed eustachian tube
    10. diminished or absent landmarks
      1. e.g., indicates thickening of the tympanic membrane from and possible chronic otitis media
    11. does not bulge slightly when the patient holds his/her nose and swallows
6. test hearing in the ears
  1. test hearing in the ears, by:
    1. standing 1 to 2 feet lateral to the right side of the patient
    2. occluding the patient's left ear with one finger of your right hand
    3. covering your mouth with your left hand
    4. softly whispering a word with two equally accented syllables
    5. asking the patient to repeat the word
    6. standing 1 to 2 feet lateral to the left side of the patient
    7. occluding the patient's left ear with one finger of your left hand
    8. covering your mouth with your right hand
    9. softly whispering a word with two equally accented syllables
    10. asking the patient to repeat the word
  2. normal findings:
    1. ability to correctly repeat the whispered word
  3. deviations from normal findings:
    1. inability to correctly repeat the whispered word
7. test for lateralization of hearing (Weber test)
  1. test for lateralization of hearing (Weber test), by:
    1. gathering a high-pitched (512 Hz) tuning fork
    2. standing directly in front of the patient
    3. holding the high-pitched (512 Hz) tuning fork in your right hand
    4. starting the high-pitched (512 Hz) tuning fork vibrating by tapping it on the heel of your left hand
    5. placing the base of the vibrating, high-pitched (512 Hz) tuning fork firmly on the top (vertex) of the patient's head or his/her forehead
    6. asking the patient where he/she heard the sound (in the right ear, left ear, or in the middle of the forehead)
  2. normal findings:
    1. vibrating sound is heard equally well in both ears
    2. no lateralization
  3. deviations from normal findings:
    1. conductive hearing loss
      1. vibrating sound lateralizes to the affected (bad) ear
        
        the affected (bad) ear is not distracted by room noise, so it can detect the vibrations of the tuning fork better than the unaffected (good) ear
        this advantage disappears in an absolutely quiet room
    2. sensorineural hearing loss
      1. vibrating sound lateralizes to the unaffected unaffected (good) ear
        
        the affected (bad) inner ear or chochlear nerve is less able to transmit impulses no matter how the sound reaches the cochlea
        the sound is, therefore, heard in the unaffected (good) ear
8. test air conduction (AC) and bone conduction (BC) (Rinne test)
  1. test air conduction (AC) and bone conduction (BC) (Rinne test), by:
    1. gathering a high-pitched (512 Hz) tuning fork
    2. standing directly in front of the patient
    3. holding the high-pitched (512 Hz) tuning fork in your left hand
    4. starting the high-pitched (512 Hz) tuning fork vibrating by tapping it on the heel of your right hand
    5. placing the base of the vibrating, high-pitched (512 Hz) tuning fork firmly on the mastoid process behind the patient's right auricle level with his/her external auditory canal
    6. asking the patient to say "now" when he/she can no longer hear the vibrating sound
    7. quickly placing the vibrating, high-pitched (512 Hz) tuning fork close to the external auditory canal of the patient's right ear
    8. asking the patient to say "now" when he/she can no longer hear the vibrating sound
    9. holding the high-pitched (512 Hz) tuning fork in your right hand
    10. starting the high-pitched (512 Hz) tuning fork vibrating by tapping it on the heel of your left hand
    11. placing the base of the vibrating, high-pitched (512 Hz) tuning fork firmly on the mastoid process behind the patient's left auricle level with his/her external auditory canal
    12. asking the patient to say "now" when he/she can no longer hear the vibrating sound
    13. quickly placing the vibrating, high-pitched (512 Hz) tuning fork close to the external auditory canal of the patient's left ear
    14. asking the patient to say "now" when he/she can no longer hear the vibrating sound
  2. normal findings:
    1. AC of the vibrating sound is heard twice as long as BC of the vibrating sound
  3. deviations from normal findings:
    1. conductive hearing loss
      1. BC of the vibrating sound heard longer or equal to AC of the vibrating sound in the affected (bad) ear
      2. BC is heard longer than or is equal to AC in affected (bad) ear
      3. formula is the following: BC is greater than AC or BC = AC
      4. while air conduction through the external or middle ear is impaired, vibrations through bone bypass the problem to reach the cochlea
    2. sensorineural hearing loss
      1. AC of the vibrating sound heard longer (but not twice as longer) than BC of the vibrating sound in the affected (bad) ear
      2. AC is heard longer (but not twice as longer) than BC in affected (bad) ear
      3. formula is the following: AC is greater than BC
      4. the inner ear or cochlear nerve is less able to transmit impulses regardless of how the vibrations reach the inner ear or cochlear nerve so the normal patterns prevails

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This page was last modified on 1/1/02