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The Outer Ear

The Outer Ear. SPA 4302 Summer 2007. 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:

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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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