Session 6 - Ear anatomy Flashcards Preview

Semester 4 - Head and Neck > Session 6 - Ear anatomy > Flashcards

Flashcards in Session 6 - Ear anatomy Deck (37)
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1
Q

What are the three main parts of the ear?

A

The external, middle and internal ear.

2
Q

What is the main, visible part of the external ear?

A

The auricle

3
Q

What are the three main features of the external ear?

A

The helix
The tragus
The lobule

4
Q

What is the blood supply to the external ear?

A

The posterior aurcular and superficial temporal arteries, which are both branches of the external carotid artery

5
Q

What is the sensory innervation anterior to the external acoustic meatus?

A

Auriculotemporal nerve, a branch of the mandibular nerve

6
Q

What is the sensory innervation of auricle behind the EAM

A

Great auricular nerve

7
Q

Outline the structure of the EAM canal

A

Cartaliginous tube for the lateral 1/3rd, bony canal for the medial 2/3rds

8
Q

Where does EAM lie?

A

In the temporal bone

9
Q

What is the gooey stuff in ears?

A

Cerumen, which mixes with dead skin cells to form wax

10
Q

What is the best way to view the EAM in adults?

A

Pull the ear upwards and backwards

11
Q

What is the best way to view the EAM in children?

A

Auricle is pulled downwards and backwards

12
Q

What can be visualised through the tympanic membrane?

A

The malleus

13
Q

What is the external surface of the tympanic membrane innervated by?

A

Auriculotemporal nerve branch of CN V3

Auricular branch of the vagus nerve CN X

14
Q

What is the internal surface of the tympanic membrane supplies by?

A

The glossopharyngeal nerve

15
Q

What is Arnold’s cough reflex?

A

Stimulation of the auricular branch of the vagus nerve, by touching the tympanic membrane with a cotton bud, can cause cough/vomiting

16
Q

What is wrong with the tympanic membrane if you can see dense white plaques?

A

Tympanosclerosis

17
Q

What does bulging of the tympanic membrane mean?

A

Pus or fluid in middle ear (otitis media)

18
Q

What would a retracted tympanic membrane demonstrate?

A

Infratympanic cavity pressures reduced due to obstruction of eustachian tube

19
Q

What is found in the middle ear?

A
Auditory ossicles 
- Malleus 
- Incus
- Stapes
Stapedius and tensor tympani msucles
Chorda tympani nerve 
Tympanic plexus of nerves
20
Q

What are the two parts of the cavity of the middle ear?

A

Tympanic cavity proper

Epitympanic recess

21
Q

What is found in the tympanic cavity proper?

A

Connected anteromedially with the nasopharynx by the eustachian tube
Connected posterolaterally with the mastoid air cells through the mastoid antrum

22
Q

What is the tympanic cavity lined by and what is it continius with?

A

Mucous membrane, continous with lining of the pharyngotympanic tube, mastoid air cells and mastorid antrum

23
Q

When is the mastoid antrum open?

A

During swallowing, thanks to the action of the palate muscles

24
Q

What is the porpoise of the ossicles?

A

Relay the vibrations encountered by the tympanic membrane to the internal ear, amplifying and concentrating sound energy to the oval window

25
Q

What are the two parts of the malleus?

A

Handle is attached to the tympanic membrane

Body articulates with the body of the incus

26
Q

What does the incus articulate with?

A

The stapes

27
Q

What does the stapes articulate with?

A

THE BONY LABYRINTH OF THE INNER EAR AT THE OVAL WINDOW

No need to shout :(

28
Q

Outline the location and role of the tensor tympani

A

o Inserts into the handle of the malleus
 Pulls handle medially
 Tenses the tympanic membrane, reducing the amplitude of its oscillations
o Prevents damage to the inner ear when exposed to loud sounds

29
Q

Outline the location and role of the stapedius

A

o Pulls the stapes posteriorly and tilts its base in the oval window
 Tightens the anular ligament and reduces the oscillatory range
o Prevents excessive movement of the stapes
o Nerve to Stapedius arises from the Facial Nerve (CN VII)

30
Q

What is the most important anatomical relationhsip of the middle ear?

A

The facial nerve, which lies in the facial canal separated from the tympanic cavity by a very thin bony partition

31
Q

Where is the inner ear found?

A

In the petrous temporal bone. This bone forms bony labyrinth, surrounding the membranous labyrinth

32
Q

What five structures does the inner ear contain?

A
Vestibule 
Semi-circular ducts and canals
Choclea
Cochlear duct
Organ of corti
33
Q

What is the vestibule of the inner ear?

A

 Small bony chamber, containing the Utricle and Saccule, which are sensitive to rotational acceleration and the static pull of gravity

34
Q

What is the semi-circular ducts and canals?

A

 Communicate with the vestibule

 Contain receptors that respond to Rotational Acceleration in three different planes

35
Q

What is the cochlea?

A

 Shell shaped portion of the bony labyrinth containing the Cochlear Duct

36
Q

What is the cochlear duct?

A

 Accommodates the spiral Organ of Corti

37
Q

What is the organ of corti?

A

 Contains the receptors of the auditory apparatus