Anatomy & Physiology of the Auditory System

Question 1

Anatomical Directions: Superior vs. Inferior

Answer 1

• Superior - upper

* Inferior - lower

Question 2

Anatomical Directions:

Medial vs. Lateral

Answer 2

• Medial - towards the midline (e.g., looking into the ear)

* Lateral - away from the midline (e.g., looking out of the ear)

Question 3

Anatomical Directions:

Anterior vs. Posterior

Answer 3

• Anterior - towards the front

* Posterior - towards the back

Question 4

Anatomical Direction:

Ventral vs. Dorsal

Answer 4

• Ventral - front surface (on animals ventral refers to the belly)
• Dorsal - back surface (on animals dorsal refers to the back)

Question 5

Anatomical Sections: Saggital

Answer 5

• aka median

* left & right

Question 6

Anatomical Sections: Transverse

Answer 6

• aka horizontal

* top & bottom

Question 7

Anatomical Sections: Coronal

Answer 7

• aka frontal

* front & back

Question 8

Peripheral vs. Central Auditory System

Answer 8

Peripheral System
• Outer Ear
• Middle Ear
• Inner Ear
• 8th/Auditory Nerve (Proximal/Cochlear end)

Central System
• 8th/Auditory Nerve (Distal/Brainstem end)
•Auditory Brainstem nuclei
• Auditory Cortex

Question 9

8th Cranial Nerve aka…

Answer 9

• Vestibulocochlear Nerve
• Auditory or Cochlear Nerve (auditory branch)
• Vestibular Nerve (vestibular branch)

Question 10

Audiologists assess the function of the peripheral & central auditory system to…

Answer 10

…diagnose hearing loss, & if present, aid in determining site of lesion & pathology

Question 11

Temporal Bone

Answer 11

• The bulk of the peripheral auditory system is housed within the temporal bone
• 5 sections
  - Squamous
  - Mastoid 
  - Tympanic Part (portion)
  - Styloid process 
  - Petrous (pyramid)

Question 12

Temporal Bone: Squamous

Answer 12

• very thin flat plate

* anterior to the ear

Question 13

Temporal Bone: Mastoid

Answer 13

• contains the mastoid process 
• forms portion of EAC 
• used in BC testing 
• honeycombed (NOT solid bone)
   - Prone to infection
   - Mastoiditis: fluid that got 
     into mastoid bone

Question 14

Temporal Bone: Tympanic Part (portion)

Answer 14

• bony part of the ear canal

Question 15

Temporal Bone: Styloid process

Answer 15

• Does not contribute to the auditory system

* attachment point for tongue & larynx muscles

Question 16

Temporal Bone: Petrous (pyramid)

Answer 16

• very hard

* contains the inner ear & internal auditory meatus through which the 8th CN travels

Question 17

The Outer Ear consists of the:

Answer 17

• Pinna (aka Auricle)
• External Auditory Meatud (aka Ear Canal)
• Tympanic Membrane (eardrum)?
   -much debate on whether 
    the TM is part of the outer 
    or middle ear

Question 18

Construction of the Pinna

Answer 18

• Externally visible aspect of the ear 
• Primarily constructed from elastic cartilage
   -also contains some muscle 
    tissues (most are non 
    functioning)
• Fat pad in the lobule

Question 19

Pinna Landmarks

Answer 19

• Helix
• Tragus
• Inter-Tragal Notch
• Anti-Tragus
• Concha
• Anti-Helix
• Triangular Fossa
• Scaphoid Fossa
• Crus of the Helix

Question 20

Pinna Landmark: Helix

Answer 20

• ridged rim along most of the perimeter of the pinna

Question 21

Pinna Landmark: Tragus

Answer 21

• posterior directed projection or ridge

Question 22

Pinna Landmark: Inter-Tragal Notch

Answer 22

• space b/w the tragus & anti-tragus

Question 23

Pinna Landmark: Anti-Tragus

Answer 23

• upward-pointing mound that is located posteroinferior to the tragus & superior to the earlobe

Question 24

Pinna Landmark: Concha

Answer 24

• cup-shaped depression

* entrance to the EAC

Question 25

Pinna Landmark: Anti-Helix

Answer 25

• Ridge anterior to the scaphoid fossa

Question 26

Pinna Landmark: Triangular Fossa

Answer 26

• triangle-shaped depression

Question 27

Pinna Landmark: Scaphoid Fossa

Answer 27

• furrow just anterior to the helix

Question 28

Pinna Landmark: Crus of the Helix

Answer 28

• ridges that connect helix to anti-helix