1. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 The human auditory system can be
divided into two sub-systems.
They are:
1. The peripheral auditory system
2. The central auditory system

2. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 The peripheral auditory system is further
divided into three segments:
1. The external ear
2. The middle ear
3. The inner ear

3. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 The external ear is comprised of two parts.
They are:
1. The external auditory meatus (ear canal)
2. The auricle (pinna)

4. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
The Auricle or Pinna is the soft tissue forming
a cup to the entrance of the external auditory
meatus (ear canal)

5. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 There are two major contributions to the
auditory system attributable to the external
ear. They are:
1. It facilitates auditory sensitivity by providing
a low-resistance path to the auditory
mechanism.
2. The acoustic properties of the external
auditory meatus serve to increase one
portion of the frequency spectrum.

6. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 Between the sound collection of the Pinna and
the shape of the ear canal, there is a natural
peak acoustic resonance of about 15 decibels
at 2700Hz.
Note: This resonance is variable from ear to ear.

7. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
Perhaps a third contribution to the
auditory system by the external ear is to
provide information regarding the
localization of a sound.
The difference between sound arrival and
collection by the Pinna, offer enhanced
information to assist with sound
localization.

8. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 The characteristic landmarks of the
Pinna are important to remember.
 Let’s review the more important
landmarks.

9. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR

10. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR

11. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR

12. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 Helix
 Scaphoid Fossa
 Antihelix
 Antitragus
 Lobule
 Tragus
 Concha
 Triangular Fossa
 Intertragal Notch

13. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 Theadult external auditory meatus is
about an one and one-half inches long
and generally and S shape.

14. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 The ear canal can be described in two
distinct portions. They are:
1. The cartilaginous portion (closest to the
opening of the ear canal).
2. The bony portion (closest to the typmanic
membrane/eardrum).

15. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 In
the outer third (the cartilaginous
portion), you have two sets of glands
and also hair follicles.

16. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 The sebaceous glands produce oil.
 The ceruminous glands produce wax.
 The hair, oil, and wax all serve to protect
the ear canal and eardrum from foreign
materials.

17. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 Otoscopic viewing of the adult ear canal
requires pulling up and back on the
pinna to straighten the ear canal for
observation of both it and the eardrum.

18. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 The view of the eardrum is broken into
four quadrants. It is important to
remember these four quadrants as you
will use them often in writing
patient/client reports.

19. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
The four quadrants are:
1. Anterior inferior (where you find the cone of light)
2. Anterior superior
3. Posterior superior
4. Posterior inferior

20. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR

21. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR

22. SENSITIVITY & LANDMARKS OF THE EXTERNAL EAR
 Let’s
practice “getting acquainted” with
our otoscopes and ear canal inspection
process.