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External Ear
- 1. External Auditory Canal - opening of external ear
- 2. Tympanic Membrane (ear drum) - separates the external and middle ear. Translucent membrane with a pearly gray color
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Middle Ear
- tiny air filled cavity inside the temporal bone
- 1. Malleus - tiny ear bones or auditory ossicles
- 2. Incus - tiny ear bones or auditory ossicles
- 3. Stapes - tiny ear bones or auditory ossicles, opens to TM
- 4. Eustachian Tube - connects middle ear with the nasopharynx and allows passage of air. The tube is normally closed, but it opens with swallowing or yawning
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Middle Ear Function
- a. Conducts sound vibrations from the outer ear to the central hearing apparatus in the inner ear
- b. Protects the inner ear by reducing the amplitude of loud sounds
- c. Eustachian Tube - allows equalization of air pressure on each side of the TM so that the membrane does not rupture
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Inner Ear
- 1. Bony Labyrinth - holds sensory organs for equilibrium and hearing
- a. Vestibule - compose the vestibular apparatus
- b. Semicircular Canals - compose the vestibular apparatus
- 2. Cochlea - contains the central hearing apparatus
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Hearing
- A. Peripheral - ear transmits sound and converts its vibrations into electrical impulses which can be analyzed by the brain
- B. Brain Stem - binaural interaction, permits locating the direction of a sound in space as well as identifying the sound
- C. Cerebral Cortex - Interpret the meaning of the sound and begin the appropriate response
- D. Pathway of Hearing - normal pathway of hearing is air conduction; alternate route of hearing is by bone conduction (bones of the skull vibrate - vibrations are transmitted directly to inner ear and to cranial nerve VIII)
- E. Hearing Loss - Anything that obstructs the transmission of sound impairs hearing
- 1. Conductive Hearing Loss - involves a mechanical dysfunction of the external or middle ear
- 2. Sensorineural (or Perceptive) Hearing Loss - pathology of inner ear, cranial nerve VIII or the auditory areas of the cerebral cortex
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Equilibrium
- labyrinth (inner ear) constantly feeds information to your brain about your body’s position in space
- A. Vertigo - strong, spinning, whirling sensation
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Transcultural Considerations
- A. Otitis Media - increased incidence and severity in Native American, Alaskan, Canadians and Hispanics. Otitis media also increased incidence in premature
- infants, Down Syndrome and bottle fed infants.
- B. Cerumen - Asians and Native Americans usually have a dry flaky cerumen; Caucasian and African Americans/Blacks usually have wet/moist cerumen
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History (Subjective)
- A. Ear aches, ear pain, hx of ear infections - adult, childhood, frequency, tx.
- B. Ear d/c or difficulty hearing.
- C. Any trouble/difficulty hearing
- D. Loud noise exposures, environmental noise - home or work exposures
- E. Hx Tinnitus
- F. Hx Vertigo
- G. Self Care - how are ears cleaned, last time hearing evaluated
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Physical Exam/Assessment of Ears (Objective)
- A. Inspect and palpate the size and shape of the external ear
- B. Observe for tenderness with external palpation
- C. Otoscopic Examination
- 1. External Canal - note any redness, swelling, lesions foreign bodies or d/c
- 2. Tympanic Membrane - color & characteristic, LR, landmarks, position
- D. Hearing Acuity - audiometry or crude test with conversation
- E. Voice Test - whisper 2 syllable word at 2 feet distance - cover lips/mouth
- F. Tuning Fork Test -
- 1. Weber - vibrating tuning fork in the middle of the persons skull and ask if the tone sounds the same in both ears or better in one
- 2. Rinne Test - compares air conduction and bone conduction sound (place the stem of the vibrating tuning fork on the mastoid process and ask them
- when the sound goes away. Quickly invert fork so vibrating end is near the ear canal. Normal - sound is heard 2X as long by air conduction as by bone conduction AC>BC
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Ear Abnormalities
- A. Otitis Externa
- B. Otitis Media
- C. Serous Otitis Media
- D. Sebaceous Cyst
- E. Perforation
- F. Darwin’s Tubercle
- G. Tophi
- H. Cerumenosis
- I. Foreign Body
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