The Outer Ear

Question 1

11 Parts of the Pinna

Answer 1

• Helix
• Crus
• Lobe
• Triangular Fossa
• Intertragal Notch
• Scaphoid Fossa
• Concha Bowl
• Aperture
• Tragus
• Antitragus
• Antihelix

Question 2

What does the outer portion of the canal (ear canal) contain?

Answer 2

Cilia (tiny Hairs), Ceruminous glands (wax) and sebaceous (oil) Glands

Question 3

Adult Ear Canal Length

Answer 3

Varies from 1” to 1 3/8” and 1/4” in diameter

Question 4

Where the canal becomes narrow as it enters the temporal bone

Answer 4

Isthmus

Question 5

Average resonant frequency of an ear canal

Answer 5

Aprox. 2700Hz

Question 6

Where is the vagus nerve (X Cranial Nerve)

Answer 6

Lies along the bottom of the canal, between the outer opening and isthmus

Question 7

The Size of the eardrum is

Answer 7

Aprox. 1/4” high and 3/8” wide

Question 8

The three layers of the ED

Answer 8

Skin of the Ear canal, which also likes the outer surface of ED
Fibrous Layer- Outermost fibers are like spokes on a wheel, inner fibers are concentric, all together they support the membrane
Mucous Membrane- Lines the middle ear cavity

Question 9

What holds the eardrum in place and forming an air/water tight seal between external/middle ear

Answer 9

Annulus or annular ring

Question 10

Vibrations of sound enhanced by pinna and ear canal resonance and causes ED to move back and forth

Answer 10

Acoustic Energy

Question 11

What is attached to the ED and is suspended to a point of 2/3 of the way down the drum

Answer 11

Malleus

Question 12

Point of greatest retraction on ED

Answer 12

Umbo

Question 13

Atresia

Answer 13

closure of the external Auditory Canal

Question 14

An inflammation of the walls of the External Auditory Canal that usually do not cause a loss unless the swelling blocks the canal

Answer 14

Otitis Externa

Question 15

Masses of tissue that grow outward from a surface

Answer 15

Polyps

Question 16

Look like a hole but reflect light, they were once holes that healed

Answer 16

Monomeric Spots

Question 17

Occurring in the middle ear and sometimes perforates the upper portion of the ED invading canal, constant odorous discharge

Answer 17

Cholesteatoma

Question 18

White chalky calcium deposits caused by a degeneration of the tissue on ED

Answer 18

Tympanosclerosis

Question 19

Bony growths that occur in the ear canal vary in size and location, usually harmless but can pose issues when conducting a HT or during impressions

Answer 19

Exostosis

Question 20

The Adult Ear canal:

Answer 20

Rises upward and forward then descends to the drum

Question 21

The isthmus is:

Answer 21

Where the canal narrows to enter the temporal bone

Question 22

The pinna and the external canal together:

Answer 22

Gather to reinforce acoustical signal
With irregular shape of the auricle, cause increase and decrease at different frequencies as the sound arrives at the ear
Forms a resonating tube

Question 23

The dividing line between the external ear and middle ear is the:

Answer 23

Tympanic Membrane

Question 24

Which is not apart of the tympanic membrane

• Pars tensa
• crus
• pars flaccida
• umbo

Answer 24

Crus

Question 25

Perforations of the ED can be caused by:

Answer 25

An infection
Nearby explosion
Fracture of the temporal bone

Question 26

What surgical technique repairs the tympanic membrane

Answer 26

Myringoplasty

Question 27

A cholesteatoma can be described as:

Answer 27

A pouch of skin filled with epithelial debris

Question 28

A swollen ear may be caused by

Answer 28

Eczema
Otitis externa
Dermatitis

Question 29

A tympanic membrane perforation may cause a :

Answer 29

Conductive loss