Ears

• Ear


  The serve organ of hearing and equilibrium
• Ear


  • Consists of three distinct parts: External ear, middle ear and inner ear
• Tympanic membrane


  Separates the external ear from the middle ear
• External ear


  • Composed of the auricle, or pinna and the external auditory canal
• Middle ear


  • A small, air-filled chamber in the temporal bone
• Distinct landmarks of the tympanic membrane


  • Handle and short process of the malleus
  • Umbo
  • Cone of light
  • Pars flaccida
  • Pars tensa
• Middle ear


  • Contains three auditory ossicles: malleus, incus and stapes
• Auditory ossicles


  Responsible for transmitting sound waves from the eardrum to the inner ear through the oval window
• Eustachian tube


  Connects the middle ear to the nasopharynx, equalizing air pressure on both sides of the tympanic membrane
• Inner ear


  • Fluid-filled and made up of the bony labyrinth and an inner membranous labyrinth
• Parts of the bony labyrinth

  • Cochlea
  • Vestibule
  • Semicircular canals
• Cochlear duct


  Contains the spiral organ of Corti, the sensory organ for hearing
• Vestibule and semicircular canals

  • Contain sensory receptors that detect position and head movement to help maintain equilibrium
• Hearing


  1. Sound vibrations traveling through air are collected and funneled through the external ear, causing the eardrum to vibrate

  2. Vibrations of the eardrum cause the malleus, incus, and stapes to vibrate

  3. Transmission of sound waves through the external and middle ear is referred to as conductive hearing

  4. Transmission of sound waves in the inner ear is referred to as perceptive or sensorineural hearing
• Conductive hearing loss


  Related to dysfunction of the external or middle ear
• Sensorineural hearing loss


  Related to dysfunction of the inner ear
• The bones of the skull also conduct sound waves
• A sudden decrease in ability to hear in one ear may be associated with otitis media, earwax (cerumen) impaction, or foreign body obstruction
• Sudden sensorineural hearing loss (SSHL) or sudden deafness can also occur
• Cochlear duct


  Contains the spiral organ of corti, which is the sensory organ for hearing
• Ear


  Sense organ for hearing and equilibrium, consisting of external, middle, and inner ear
• Hearing


  1. Sound vibrations traveling through air are collected by the ear, causing the eardrum to vibrate

  2. Sound waves are transmitted through the auditory ossicles (malleus, incus, stapes) to the inner ear

  3. Vibrations are converted into nerve impulses that travel to the brain for interpretation
• Conductive hearing


  Sound waves are transmitted through the external and middle ear
• Sensorineural hearing


  Nerve impulses are transmitted from the inner ear to the brain
• Conductive hearing loss


  Occurs when something blocks or impairs the passage of vibrations to the inner ear
• Sensorineural hearing loss


  Occurs when there is damage to the inner ear or nerve pathways to the brain
• Presbycusis


  • Gradual sensorineural hearing loss due to degeneration of the cochlea or vestibulocochlear nerve, common in older adults
  • Difficulty hearing consonants and whispered words, increases over time
• Otosclerosis


  Fusion of the auditory ossicles in the middle ear over time, obstructing the transmission of sound waves
• Otitis externa


  Fungal ear infection that can occur when water stays in the ear canal for long periods, causing pain
• Cerumen (earwax) buildup and fluid in the middle ear are the most common barriers to sound transmission</b>
• Conductive hearing impairment is more common in older clients due to greater incidence of cerumen buildup and/or atrophy or sclerosis of the tympanic membrane
• Abnormal findings of the external ear and ear canal include infections and abnormal growths, such as polyps and cholesteatomas
• Abnormalities of the tympanic membrane include retraction, bulging, scarring, perforation, and the presence of tympanostomy tubes
• Hearing tests are performed to assess the type and degree of hearing loss, and to identify potential problems with equilibrium