The Middle Ear

Question 1

The tympanic bulla of the temporal bone is a bony shell situated caudal and medial to the (2)

Answer 1

zygomatic and temporomandibular joint (TMJ)

Question 2

What is the middle ear lined with?

Answer 2

respiratory epithelium

Question 3

What is the middle ear continuous with?

Answer 3

Nasopharynx

Question 4

The tympanic bulla in the dog is divided into (2) and what by?

Answer 4

dorsal and ventral compartment

• an incomplete bony shelf.

Question 5

Tympanic bulla in cats; what is the division and how do they communicate?

Answer 5

Almost completely separated by a bony septum, communicating only by a small slit like medial opening which become a foramen more caudally

Question 6

The dorsal epitympanic recess contains the auditory ossicles and communicates with the inner ear through (2)

Answer 6

round and oval windows.

Question 7

What connects the middle ear to the nasopharynx and opens in the middle of the medial wall of the bulla?

Answer 7

Eustachian tube

Question 8

What nerve passes through the periosteum of the medial bulla?

Answer 8

sympathetic

Question 9

What separates the external acoustic meatus of the ear canal from the middle ear?

Answer 9

Tympanic membrane

Question 10

The majority of the tympanic membrane is the ?

Answer 10

pars tensa

Question 11

pars tensa:
A) What does this look like?
B) What is embedded here?

Answer 11

A) grey-white, translucent, taut membrane
B) malleus

Question 11

Which “fleshier” part of the TM sits dorsally?

Answer 11

pars flaccida

Question 12

What allows repair of the TM?

Answer 12

There is a constant centrifugal movement of cells that clear debris from the surface of the membrane

Question 13

If the TM isn’t present; how can we gauge where it should be?

Answer 13

There are a few hairs that sit at the ventral insertion of the tympanic membrane

Question 14

The tympanic cavity in cats is almost completely divided into:
A) a large ventral cavity called?
B) and a smaller rostrolateral component (2) )
C) What is it separated by?

Answer 14

A) Hypotympanum
B) Epitympanum and mesotympanum
C) a bony septum.

Question 15

What are the ossicles of the middle ear role?

Answer 15

concentrate sound waves striking the tympanic membrane, focussing them at the smaller vestibular (oval) window.

Question 16

What are the ossicles of the middle ear connected by?

Answer 16

A series of ligaments and muscles.

Question 17

A) Where is the malleus embedded?
B) What does the head articulate with?

Answer 17

A) TM
B) Incus

Question 18

Incus:
A) What is it within?
B) What does it articulate with?

Answer 18

A) epitympanum
B) Stapes

Question 19

What is attached to a cartilaginous ring around the vestibular window – the separation between the tympanic cavity and the perilymphatic space of the inner ear.

Answer 19

Stapes

Question 20

The A) nerve enters the internal auditory meatus alongside the B) nerve.

It travels in the facial canal of the petrous temporal bone before exiting the bulla at the C) foramen. It is exposed within the dorsal D) cavity near the vestibular window.

Answer 20

A) facial
B) vestibulocochlear
C) Stylomastoid
D) Tympanic

Question 21

The tympanic plexus is formed from the tympanic branches of what nerves (2)

Answer 21

glossopharyngeal nerve

caroticotympanic nerve.

Question 22

The tympanic plexus spreads along the bony promontory and gives rise to parasympathetic fibres to the A) Which 2 salivary glands, and sensory fibres to B)

Answer 22

A) parotid and zygomatic
B) the middle ear cavity.

Question 23

What supplies the middle ear, in conjunction with the meningeal and pharyngeal arteries?

Answer 23

The tympanic artery

Question 24

What is The tympanic artery a branch of?

Answer 24

Maxillary a.

Question 25

Physiology of hearing sound?

Answer 25

The middle ear conducts sound from the external auditory meatus across the tympanic membrane, through the air-filled tympanic cavity into the fluid-filled inner ear and receptor cells of the cochlear. The ossicles focus sound that strikes the tympanic membrane to the vestibular window.

Question 26

Which of these arteries is not involved in the vascular supply to middle ear? Tympanic Maxillary Meningeal Pharyngeal

Answer 26

Maxillary

Question 27

In dogs, the most common cause of otitis media is?

Answer 27

Infection spreading from the external ear canal across the tympanic membrane.

Question 28

What are the most common organisms isolated from the canine ear canal (3)

Answer 28

Staphylococcus intermedius (pseudintermedius), Pseudomonas Malassezia

Question 29

In cats, middle ear infections most commonly arise from?

Answer 29

ascending infection through the auditory tube, often associated with episodes of nasopharyngeal viral infection.

Question 30

Middle ear infections are also implicated in the development of?

Answer 30

Middle ear polyps

Question 31

Clinical findings with otitis media? (9)

Answer 31

Pain Otorrhoea Head shaking Purulent discharges at the external meatus; The head being carried lower on the affected side pain on opening of the mouth (in cases with TMJ involvement); Facial nerve palsy/paralysis (10% of the cases); Loss of hearing vestibular signs, if the otitis media spreads to the inner ear

Question 32

What does the normal TM look like? (4)

Answer 32

is shiny translucent visible malleus and vascular structures.

Question 33

What on otoscope suggests middle ear dx? (3)

Answer 33

loss of translucency, a change in colour rupture/perforation

Question 34

If the tympanic membrane is intact but abnormal, what diagnostics should be performed? (4)

Answer 34

myringotomy is performed and samples for: - cytology, - histopathology - bacteriology should be taken.

Question 35

What is the most sensitive for detecting middle and inner ear disease?

Answer 35

MRI

Question 36

Medical management is only effective with otitis media if?

Answer 36

Disease of the external ear canal is adequately controlled.

Question 37

How to medically manage otitis media?

Answer 37

The middle ear is lavaged using warm saline to remove debris and topical and systemic antibiotics (based on culture and sensitivity results) are administered for 4-6 weeks.

Question 38

With otitis media, when i TECA +/- LBO recommended? (3)

Answer 38

If infection is established osseous changes to the tympanic bone stenosis of the external ear canal,

Question 39

Polyps of the middle ear are inflammatory in nature, arising from the epithelium of (2)

Answer 39

the tympanic chamber auditory tube

Question 40

Middle ear polyps is the most common middle ear disease in cats and is often identified in young cats following an episode of?

Answer 40

upper respiratory viral infection

Question 41

How can polyps lead to horners?

Answer 41

pressure on the tympanic plexus.

Question 42

Why may polyps cause vestibular signs?

Answer 42

sustained pressure on the inner ear,

Question 43

Polyps extending into the nasopharynx may cause what signs? (4)

Answer 43

difficulty with swallowing, nasal discharge dysphagia respiratory distress

Question 44

What breathing in cats is often suggestive of the presence of a nasopharyngeal polyp?

Answer 44

Stertorous

Question 45

How to diagnose polyps? (3)

Answer 45

Otoscope Nasopharyngeal exam under GA CT

Question 46

Treatment options of polyps?

Answer 46

Traction removal followed by oral prednisolone A ventral bulla osteotomy

Question 47

When is surgical management of polyps advised? (2)

Answer 47

neurological signs external ear polyps.

Question 48

Which of these clinical signs is suggestive of the presence of a nasopharyngeal polyp in cats? Stertorous breathing Purulent discharge Otorrhoea Head tilt

Answer 48

Stertorous breathing

Question 49

What type of mass is a Cholesteatomas?

Answer 49

Cystic

Question 50

What do Cholesteatomas arise from?

Answer 50

the squamous epithelium of the middle ear that expand over time

Question 51

What do Cholesteatoma have the potential to cause? (2)

Answer 51

local destruction of the bone of the bulla secondary inflammation

Question 52

What do most Cholesteatoma arise 2ry to?

Answer 52

Otitis media

Question 53

What signalment increases the chance of a Cholesteatoma? (2)

Answer 53

Male Brachycephalic

Question 54

Clinical signs of Cholesteatoma?

Answer 54

Similar to otitis media/externa

Question 55

Why might Cholesteatoma not be visible on otoscope when chronic? (3)

Answer 55

stenosis exudate, chronic changes

Question 56

Cholesteatoma; What is the mass seen as and where does it protrude from?

Answer 56

mass is frequently pearly white in colour and protrudes from the middle ear to the external ear canal

Question 57

Cholesteatoma; how is the TM seen?

Answer 57

Not intact

Question 58

Cholesteatoma; what is used to assess middle ear changes (3)

Answer 58

CT MRI Radiographs if above not available

Question 59

What is seen in the bulla with Cholesteatoma? (4)

Answer 59

Lysis Sclerosis Proliferation May expand and be filled with soft tissue

Question 60

With a suspected Cholesteatoma what samples should be submitted? (3)

Answer 60

Cytology Histology Culture

Question 61

What is the aim with surgery for a Cholesteatoma?

Answer 61

remove the entire epidermoid cystic structure and to strip the epithelium from the margins including the bulla wall.

Question 62

What surgical approach for a Cholesteatoma? (2)

Answer 62

Ventral osteotomy TECA - LBO

Question 63

Cholesteatoma; A) Recurrence rate? B) Surgical is curative how often?

Answer 63

A) High B) 50%

Question 64

What symptoms prior to removal have a higher chance of recurrence with a Cholesteatoma?

Answer 64

Neurological sign

Question 65

What medical management may be needed for ongoing tx of Cholesteatoma? (2)

Answer 65

Secondary infections Corticosteroids

Question 66

What neoplasia of the ear have been reported? (3)

Answer 66

Ceruminous gland adenocarcinoma, squamous cell carcinoma lymphoma

Question 67

Patients that have reduced drainage through the auditory tube have reduced hearing and may also develop ?

Answer 67

otorrhoea

Question 68

What is Secretory otitis media?

Answer 68

an accumulation of mucinous material in the tympanic cavity

Question 69

Which breed is Secretory otitis media common in?

Answer 69

CKCS

Question 70

Why might Secretory otitis media develop congenitally?

Answer 70

congenital dysfunction of auditory tube drainage

Question 71

Which breeds commonly have evidence of middle ear secretions identified on advanced imaging?

Answer 71

Brachycephalic

Question 72

Dogs that have what (2) of the soft palate are also reported to be at risk of middle ear disease, hypoplastic bullae and impaired hearing.

Answer 72

congenital hypoplasia malformations

Question 73

What is Primary ciliary dyskinesia?

Answer 73

rare congenital condition where there is a failure of middle ear drainage, leading to a build-up of mucous and cellular debris and the development of a secondary sterile otitis media.

Question 74

In patients with reduced drainage, what may provide temporary relief?

Answer 74

myringotomy

Question 75

In patients with reduced drainage, what may provide longer-term relief of sign (2)

Answer 75

Tympanostomy tubes grommets placed in the pars tensa of the tympanic membrane

Question 76

Alternative surgical tx in patients with reduced drainage?

Answer 76

TECA

Question 77

The aims of the surgical procedures of the middle ear (3)

Answer 77

eliminate the primary cause to remove debris Remove diseased tissue

Question 78

Indications for surgery for middle ear? (2)

Answer 78

Septic otitis media/interna where medical management has failed; Treatment of patients where neurologic signs are identified that may be relieved by tympanic decompression.

Question 79

The surgical approach to the middle ear is determined by the of the problem. For example, in chronic otitis externa with associated otitis media, a lateral approach with A) is ideal. In patients with otitis media and no external ear canal disease, B) is adequate e.g. cats with inflammatory polyps.

Answer 79

A) TECA - LBO B) VBO

Question 80

How is a cat positioned for a VBO?

Answer 80

dorsal recumbency. (Placement of a cervical support helps extend the neck to allow easier access to the bulla.)

Question 81

How to palpate the right area for VBO?

Answer 81

The ventral aspect of the bulla is palpated – this will lie in the triangle formed by the caudal aspect of the mandible, the mandibular symphysis and the caudal border of the larynx.

Question 82

VBO: Where is the incision?

Answer 82

The incision is centred over the bulla and a dissection down through the muscles is performed.

Question 83

VBO: Which structures need to be retracted from the site? (5)

Answer 83

mandibular salivary gland bifurcation of the linguofacial and maxillary veins hyoglossus and styloglossus muscles

Question 84

Which structure is avoided in a VBO?

Answer 84

Linguofacial vein

Question 85

VBO: The ventral aspect of the bulla is identified via palpation and a periosteal elevator is used to ?

Answer 85

strip the periosteum away from it.

Question 86

VBO: How to perform the osteotomy? (2)

Answer 86

drill increasing gauges of Steinmann pins.

Question 87

VBO: CARE! If the bony wall of the bulla has been affected by the disease process Why?

Answer 87

bone is likely to be soft and there is potential to damage the underlying bony promontory.

Question 88

VBO: What is used to remove any mucous secretions from within the hypotympanic chamber.

Answer 88

Suction

Question 89

VBO: The septum between the laterally situated hypotympanic cavity and the true middle ear is opened carefully, sticking as ?as possible to avoid damage to the promontory and the overlying nerves.

Answer 89

lateral

Question 90

VBO: 8 If present, polypoid material is removed from the A) chamber, and occasionally the B)

Answer 90

A) mesotympanic B) external acoustic meatus.

Question 91

VBO: Following removal of material. What is then performed? How is it closed?

Answer 91

Lavage and suction of the bulla is performed. Closure of the muscles over the bulla, the subcutaneous tissues and the skin is then performed.

Question 92

Complications of VBO in cats (2)

Answer 92

Horner’s syndrome Vestibular signs

Question 93

Horners syndrome in cats; usually transient, if it lasts how long it is permanent?

Answer 93

6 weeks

Question 94

Why might vestibular signs occur post VBO? (2)

Answer 94

iatrogenic during bulla curettage present pre-operatively if the polypoid material has been causing pressure on the labyrinth.

Question 95

The prognosis for recovery from inflammatory polyps following VBO is?

Answer 95

excellent.

Question 96

When is VBO indicated in dogs? (2)

Answer 96

Failed LBO (lateral bulla osteotomy) neoplastic conditions of the middle ear.

Question 97

How to position a patient for a VBO?

Answer 97

Dorsal recumbency with the neck extended and a cervical support placed

Question 98

What is the difference to the ventral aspect of the bulla in dogs compared to cats? (2)

Answer 98

- Much less obvious - situated a lot deeper within the soft tissues

Question 99

In dogs: Whatsits midway between the wing of the atlas and the angle of the mandible?

Answer 99

Bulla

Question 100

VBA in dogs: The jugular process of the skull can often be palpated, and the bulla usually lies approximately?rostral and medial to this bony prominence

Answer 100

5-10 mm

Question 101

VBO in dogs; what must be retracted medially or laterally to gain access to the bulla?

Answer 101

The digastricus muscle