Nasal Passages and Paranasal Sinuses in Horses

Question 1

What divides each nostril into dorsal and ventral cavities?

Answer 1

Alar fold

Question 2

Dorsal blind end 10cm into the nare of a horse

Answer 2

Nasal diverticulum

Question 3

What are nares supported by?

Answer 3

Alar cartilages

Question 4

What divides the nasal passages into dorsal, middle, and ventral meatus?

Answer 4

Nasal conchae

Question 5

Thin scrolls of cartilage and bone

Answer 5

Nasal conchae

Question 6

The dorsal and ventral meatus are further divided into what compartments?

Answer 6

Rostral conchal bulla

Caudal conchal sinus

Question 7

Where do most 2* infections d/t dental problems occur and why?

Answer 7

Maxillary sinus d/t molar roots

Question 8

Which molar root projects to the rostral maxillary sinus?

Answer 8

M1

Question 9

What sinuses communicate to form the conchofrontal sinus?

Answer 9

Dorsal conchal sinus and frontal sinus

Question 10

All sinuses indirectly drain through this opening and into the nasal passage

Answer 10

Nasomaxillary opening

Question 11

Communicates w/ventral conchal sinus over IO canal

Answer 11

Rostral maxillary sinus

Question 12

Communicates freely w/concofrontal sinus

Answer 12

Caudal maxillary sinus

Question 13

What is the opening between the caudal maxillary sinus and the concofrontal sinus called?

Answer 13

Fronto-maxillary opening

Question 14

Communicates with the sphenopalatine

Answer 14

Caudal maxillary sinus

Question 15

Hemorrhage in submucosa of endoturbinate

Answer 15

Progressive ethmoid hematoma

Question 16

What age group is an ethmoid hematoma more common in?

Answer 16

~10yo

Question 17

Are males or females more commonly affected by ethmoid hematomas?

Answer 17

Males

Question 18

What is the most common cause of ethmoid hematomas?

Answer 18

Idiopathic

Question 19

Mild, intermittent, unilaeteral epistaxis and facial swelling

Answer 19

Ethmoid hematoma

Question 20

Dx method useful in patients w/extensife PEH, bilateral disease, or suspected sinus involvement

Answer 20

CT

Question 21

What is the recurrence rate of an ethmoid hematoma?

Answer 21

40%

Question 22

How do you treat an ethmoid hematoma?

Answer 22

Intralesional 10% formalin injection q4wk

Question 23

When can you NOT use intralesional formalin to treat an ethmoid hematoma?

Answer 23

If cribiform plate is damaged (can cause brain damage)

Question 24

Treatment for large masses in the sinuses

Answer 24

Sinusotomy (bone flap or trephination)

Question 25

If you surgically remove an ethmoid hematoma (via bone flap), what must you have ready for the horse?

Answer 25

Blood transfusion - will bleed a lot

Question 26

What is the most common sinus disease?

Answer 26

Sinusitis

Question 27

What is 2* sinusitis caused by?

Answer 27

Dental disease, sinus cysts, neoplasia

Question 28

Fluid line on radiographs indicates what disease?

Answer 28

Sinusitis

Question 29

Unilateral, malodorous nasal discharge and inspissated pus

Answer 29

Empyema of conchal bulla

Question 30

How do you treat conchal bulla empyema?

Answer 30

Fenestrate bulla, lavage and drain, Nd:YAG laser

Question 31

Most common expansile mass in the sinuses that leads to distortion of other structures

Answer 31

Paranasal sinus cyst

Question 32

Causes deviation of the nasal septum

Answer 32

Paranasal sinus cyst

Question 33

What are uninfected paranasal sinus cysts filled with?

Answer 33

Yellow viscous fluid (like honey)

Question 34

Are paranasal sinus cysts more common in younger or older adult horses?

Answer 34

Young adults

Question 35

How do you treat a paranasal sinus cyst?

Answer 35

Sx excision + remove cyst lining

Question 36

What approach do you use for removal of a paranasal sinus cyst?

Answer 36

Fronto-nasal bone flap

Question 37

What is the most common neoplasia of the paranasal sinuses? Which sinus is most often affected?

Answer 37

SCC of caudal maxillary sinus

Question 38

Malodorous breath, swelling, and LN enlargement

Answer 38

SCC

Question 39

What will you see on CT of a maxillary sinus SCC?

Answer 39

Widespread bone destruction and a well defined mass

Question 40

What is the prognosis for SCC in the sinuses?

Answer 40

Poor

Question 41

What type of trephine is most often used?

Answer 41

Galt trephine

Question 42

Bone flap with limited access in young horses d/t tooth roots

Answer 42

Maxillary bone flap

Question 43

What are the landmarks for a maxillary bone flap?

Answer 43

Medial canthus of eye along facial crest

Question 44

Better access to the sinuse than a trephination hole

Answer 44

Bone flap

Question 45

Bone flap that is more versatile than the maxillary bone flap and provides direct access to conchofrontal and caudal maxillary sinuses

Answer 45

Frontonasal bone flap

Question 46

How can you gain access to the ventral conchal sinus and rostral maxillary sinus via frontonasal bone flap?

Answer 46

Fenestrate cadodorsal ventral concha

Question 47

How do you tell the difference between an osteotome and an elevator?

Answer 47

Ostotomes are vivalved

Question 48

What do you use to close a bone flap?

Answer 48

Skin staples

Question 49

What is the most important part of paranasal sinus surgery?

Answer 49

Drainage

Question 50

What post-sinus surgery infections are most common and how do you treat them?

Answer 50

Strep spp. tx w/penicillin and TMS

Question 51

What type of paranasal sinus surgery results in less bleeding

Answer 51

Standing