1. The Outer Ear
SPA 4302
Summer 2004

2. External Auditory Canal
lateral portion-cartilage
medial portion-osseous
lined with epidermal (skin) tissue
hairs grow in lateral part
cerumen (ear wax) secreted in lateral part.
Usually curved.

3. Outer Ear Functions 1 Amplification / Filtering
-- increases sounds between 1500 and 7000 Hz by 10 to 15 dB
-- produced by resonance of
Concha Hz
E.A.Canal Hz

4. Outer Ear Functions 2 Protection -- medial displacement of ear drum
-- curvature of canal
-- hairs
-- cerumen
-- skin migration

5. Outer Ear Functions 3 Localization
-- The ability to identify the location of a sound source

6. Otoscopy Viewing outer ear and TM Looking for: Landmarks,
Evidence of infection
Other Anomalies

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

8. Epidermal migration produces “wrinkles”

9. Disorders: Blockage: with earwax, foreign bodies, pus.
Otitis Externa: swimmer's ear.
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 hearing aids.

10. Otitis Externa

11. Cerumen

12. A Cerumen Tunnel

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

15. Another Foreign Object

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

17. exostosis

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

19. Injuries to Ear Canal

20. A Q-tip Victim

21. Squamous Cell Cancer

23. Malformations: congenital, traumatic or surgical.
Microtia: external ear is small, malformed
Atresia: 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 flat conductive hearing losses.
usually medically or surgically treatable.
additional HL if congenital --associated problems w/ cochlea
Surgical or traumatic:
mid to high frequency conductive.
prosthetics available, expensive.