NCM 101 - Ears

• External ear


  Auricle (pinna), external auditory canal
• Auricle

  portion of the ear visible without any tools
• The external auditory canal is S-shaped in the adult
• Cerumen

  A waxy-like substance that keeps the tympanic membrane soft
• Middle or tympanic cavity

  Small, air-filled chamber in the temporal bone

  Separated from the external ear by the tympanic membrane and from the internal ear by the round and oval window
• Tympanic membrane or eardrum

  Translucent, pearly gray appearance

  Concave

  Partition stretched across the inner end of the auditory canal
• Handle and short process of malleus

  Nearest auditory ossicle that can be seen through the translucent membrane
• Umbo

  The base of the malleus, center point landmark
• Pars flaccida

  Top portion of the membrane that appears to be less taut
• Pars tensa

  The bottom part or the membrane that appears to be taut
• The middle ear contains

  Malleus, incus, stapes
• Responsible for transmitting sound waves from eardrum to inner ear through the oval window

  Malleus, incus, stapes
• Eustachian tube

  Air pressure on both sides of the tympanic membrane is equalized
• fluid-filled and made up of the bony labyrinth and inner membranous labyrinth

  the inner ear, or the labyrinth
• bony labyrinth has 3 parts

  cochlea, vestibule, semi circular canal
• sensory organ for hearing

  the inner cochlear duct contains the spinal organ of corti
• sensory receptors

  located in the vestibule and the membranous semicircular canals, sense position and head movements to help mainting both static and dynamic equilibrium
• vestibular nerve

  connects with the cochlear nerve to form cranial nerve VIII
• conductive hearing

  transmission of soundwaves through the external and middle ear
• sensorineural hearing or perceptive

  transmission of sound waves in the inner ear
• conductive hearing loss

  dysfunction of the external ear
• sensorineural hearing loss

  dysfunction of the inner ear
• darwin tubercle

  small prominence on the auricle of the ear
• earwax

  produced by the apocrine glands in the external ear
• European and Africans tend to have wet earwax
• East Asians, Native American, and Eskimos tend to have dry earwax
• Japanese women with wet earwax have been shown to have higher risk of breast cancer than other Japanese women
• 466 million people accross the world have disabling hearing loss, 34 million of whom are children
• earwax is also known as cerumen
• sudden decrease in ability to hear in one ear may be associated with otits media, earwax, or foreign-body obstruction
• presbycusis often begins with a loss of high-frequency sounds followed by the loss of low-frequency sounds
• Drainage (otorrhea) usually indicates infection
• Earache (otorrhea) can occur with ear infections.
• pain caused by a fungal ear infection known as "swimmer's ear" (otitis externa)
• ringing in the ear (tinnitus)

  associated with excessive earwax buildup, high blood pressure, certain ototoxic medications
• people thar have high risk for tinnitus

  person over 60 age, active military personnel, loud environments, musicians, motor sports, and hunt enthusiasts
• Vertigo (true spinning motion)


  may be associated with an inner ear problem
• subjective vertigo

  if the client feels that they are spinning around
• objective vertigo

  if the client feels that the room around is spinning
• Ostroclerosis (fusion of the ossicle in the middle ear over time)


  obstruct the transmission of sound waves from the tympanic membrane to the inner ear, reducing hearing ability