Anatomy of the Ear and Auditory Tube Flashcards Preview

Hannah's Neuro > Anatomy of the Ear and Auditory Tube > Flashcards

Flashcards in Anatomy of the Ear and Auditory Tube Deck (24):
1

What anatomical landmarks distinguish the borders of the outer, middle and inner ear respectively?

Outer: from auricle to tympanic membrane
Middle: from tympanic membrane to round and oval windows
Inner: cavity extending into the petrous part of the temporal bone from the round and oval windows

2

What is the role of the auricle?

Cartilaginous structure which helps to collect sound

3

Describe the nervous supply of the external acoustic meatus

Vagus supplies the posteroinferior walls
Auriculotemporal (from CNV3) supplies anterosuperior walls and external surface of tympanic membrane

4

What is the significance of the nerve supply of the tympanic membrane?

Pain can be referred to or from other branches of CNV3 (e.g. lower teeth)

5

What lines the external acoustic meatus and why?

Hairy skin and cerumen glands to prevent maceration of the skin with water

6

Describe the structure of the external acoustic meatus

Lateral 1/3 is cartilaginous
Medial 2/3 is bony (temporal bone)

7

What is the role of tympanic membrane?

Vibrates with the frequency and amplitude of the incoming sound to transfer this sound through to the inner ear via the ossicles

8

What is the significance of the "cone of light" seen through an oroscope when examining the tympanic membrane?

Should be located in the anteroinferior quadrant; light reflecting elsewhere may indicate a pressure build-up behind the tympanic membrane

9

What is the epitympanic recess?

An opening above the tympanic membrane that communicates posteriorly with the mastoid air cells

10

What is the role of the auditory tube?

Projects anteroinferiorly to the nasopharynx allowing for equalization of pressure to the middle ear and drainage of inflammatory exudate

11

What is the difference between the auditory tube in childhood and adulthood and how is this clinically relevant?

More horizontally orientated in childhood, meaning drainage is more difficult and children are therefore more prone to infections of the middle ear
These infections can affect hearing as the mucus stifles the movement of the ossicles

12

What is the name of the main cavity in the middle ear?

Tympanic cavity proper

13

What are the 3 ossicles of the middle ear, in order of most lateral to most medial?

Malleus, incus, stapes

14

What is the name of the process projecting from the malleus that communicates with the tympanic membrane?

Handle

15

What is the name of the process projecting from the body of the incus to articulate with the head of the stapes?

Lenticular process

16

What is the role of the stapedius and tensor tympani muscles?

To dampen the amplitude of vibration when the volume of sound is excessive

17

Which nerve innervates stapedius?

CNVII

18

Which nerve innervates tensor tympani?

Trigeminal

19

Where does stapedius attach?

To stapes

20

Where does tensor tympani attach?

To malleus

21

Which ossicle overlies the oval window?

Stapes

22

Describe the course of the internal carotid artery

Runs straight underneath the middle ear through the carotid canal, and makes an S-shaped bend at foramen lacerum

23

Describe the structure of the inner ear

A bony labyrinth filled with perilymph, containing a membranous labyrinth filled with endolymph

24

List the 4 different components of the membranous labyrinth

Vestibule containing utricle and saccule
Cochlea with cochlear duct
Anterior, horizontal and posterior semicircular canals
Ampullas