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The Outer Ear

Learn about the fascinating development of the outer ear and its important functions. Explore the anatomy, disorders, and potential malformations related to the outer ear structure. Enhance your understanding of otoscopy, external auditory canal features, and preventive measures for common ear issues.

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The Outer Ear

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  1. The Outer Ear SPA 4302 Summer 2007

  2. Development of the Outer Ear • About __________ after conception the pharyngeal arches develop (bulges on the area of the embryo that will later develop into the head and neck) • As many as ____ all separated by grooves and clefts • First three: • __________ arch • __________ arch • ____________________ arch

  3. Development of the Outer Ear • Each of the arches has three layers • _______________ (outer layer) • _______________ (middle layer) • _______________ (inner layer) • Each arch contains four components: • An artery, muscle and cartilage (from mesoderm) • Nerve (from _______________) • Aurical develops from the first 2 pharyngeal arches • EAC develops from the first pharyngeal groove • TM develops from ______________: inner layer from endoderm, middle layer from mesoderm, and outer layer from ectoderm

  4. External Auditory Canal • lateral portion-__________ • medial portion-_________ • lined with epidermal (skin) tissue • hairs grow in lateral part • cerumen (ear wax) secreted in lateral part. • Usually curved.

  5. Outer Ear Functions 1 • Amplification / Filtering -- 1500 to 7000 Hz increased by ________________ -- produced by resonance of Concha (_______ kHz) & E.A.Canal (_____________ Hz)

  6. Outer Ear Functions 2 • Protection -- medial displacement of ___________ -- curvature of canal -- _____________ -- cerumen -- _____________

  7. Outer Ear Functions 3 Localization -- The ability to _____________________ of a sound source

  8. Otoscopy • Viewing outer ear and TM Looking for: • _____________, • Evidence of infection • Other __________

  9. Lateral Process (Malleus) = Annulus Malleus Manubrium Umbo Cone of Light

  10. Epidermal migration produces “wrinkles”

  11. Disorders of the Pinna: • Microtia- ___________________________ • Anotia- ____________________________ • Congenital malformation associated with syndromes and disorders • _____________- surgery performed to correct a pinna that either protrudes markedly from head or is pinned to closely

  12. Disorders: • Blockage: with earwax, foreign bodies, pus. • Otitis Externa: ________________. • Fungal or Bacterial in origin. • More frequent in ears with small canal • openings that cannot dry out as easily. • This is also sometimes a problem for people wearing _____________-.

  13. Otitis Externa

  14. Cerumen

  15. A Cerumen Tunnel

  16. Car Accident Victim Who just didn’t “feel right” afterward…

  17. Another Foreign Object

  18. Exostoses: Benign bony growths in the outer ear canal • Contrast with Osteomas

  19. A False Tympanic Membrane • A layer of dead skin cells builds up in persons who use earplugs or some hearing aids frequently

  20. Injuries to Ear Canal

  21. AQ-tip Victim

  22. Squamous Cell Cancer

  23. Malformations: congenital, traumatic or surgical. • ______________: external ear is small, malformed • ______________: ear canal is closed off. • Post-cancer surgery.

  24. Congenital Malformation

  25. Microtia

  26. Anotia: Pre- and Post-Op

  27. Mastoiditis

  28. Hearing Loss accompanying these disorders: • Blockage or atresia: • moderate ________________ hearing losses. • usually medically or surgically treatable. • additional HL if _______________--associated problems w/ cochlea • Surgical or traumatic: • ___________- frequency conductive. • prosthetics available, expensive.

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