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RUSVM SAM 2 > Orbit > Flashcards

Flashcards in Orbit Deck (35):
1

What do you call the supportive structure of the eye that contain the eyeball, extraocular muscles, fat, vessels, nerves, and fascia?

Periorbital cone

2

What sinuses surround the orbit?

Frontal and maxillary

3

Inflammation of what salivary gland can lead to displacement of the globe?

Zygomatic

4

What are the muscles of mastication?

Masseter
Temporalis
Pterygoid

5

What bony structure can compress inflamed orbital soft tissue causing severe pain?

Paramus of the mandible

6

Why do we avoid mouth gags in cats?

Risk of blindness

If mouth is opened to widely Ramus of manbidle compresses maxillary and carotid artery, reducing blood flow

7

What nerves exit the optic canal??

CN2 optic

8

Which nerves exit the orbital fissure?

CN III - oculomoror
CN IV - trochlear
CN V - ophthalmic branch of trigeminal
CN VI- abducens

9

What is cavernous sinus syndrome?

Venous sinus located near the orbital fissure that allows passage of ophthalmic nerves

Infection/inflammation/neoplasia/vascular disorders can disrupt nerve function leading to the following clinical signs..

External ophthalmoplegia
Internal ophthalamoplegia
Ptosis
Reduced corneal and medial canthal sensation
Reduced lateral canthal sensation

10

T/f: both cats and dogs have an orbital ligament that forms the boundary of the orbital rim

True

11

What features of the brachycephalic skull make them very susceptible to trauma related ocular diseases??

Relative to skull size, the orbital ligament spans a greater portion of the orbital rim in brachycephalic

Orbit is much shallower in brachycephalic

12

What species have closed orbital rims?

Cows, horses

13

What do you call abnormal protrusion of the eye from the orbit?

Exopthalamos

14

What are clinical signs associated with exopthalmos?

Third eyelid protrusion
Facial swelling
Soft palate bulging
Pain on opening mouth
Fever

15

What are common causes of exopthalmos?

Orbital volume imbalance

Neoplasia *
Cellulitis/abscess *
Zygomatic salivary gland mucocele
Masticatory muscle myositis
Extraocular myositis
Retrobulbar hemorrhage

16

What do you call an enlargement of the globe? What is the only cause of this>?

Buphthlamos

Glaucoma

17

You have a dog with exophthalamos.. what will your diagnostic approach be?

Complete ophthalmic exam
-test orbital symmetry
-oral exam

CBC and Chem
Chest rads
Advanced imaging

Tissue sampling
-FNA or biopsy

18

You discover your patient has as orbital neoplasia. What two treatment methods are there?

Globe sparing — palliative, radiation, surgical exploration, chemo


Globe removal
-enucleation — removal of the eye
-exenteration — removal of the eye and all orbital contents

19

Your patient has orbital cellulitis/abscess. What two treatments are available ?

Medical
- NSAIDS and antibiotics

Surgical exploration/ drainage

20

What do you call an abnormal recession of the eye within the orbit?

Enophthalamos

21

Common clinical signs of enophthalamos?

Facial muscular loss
Third eyelid protrusion
Entropion

22

What are three common mechanisms of enophthalamos ?

Orbital volume imbalance
Eg dehydration, emaciation, myopathies, space occupying lesion of anterior globe

Active globe retraction
Eg ocular pain — retractor bulbi muscle

Passive glob retraction
Eg horners syndrome — loss of sympathetic tone

23

What do you call a congenitally small globe?

Microphthalamos

Seen in collies

24

What do you call an aquired shrunken globe, usually from severe/chronic inflammation?

Phthisis bulbi

25

What do you call a deviation of one or both eyes, so that both eyes are not directed at same object?

Strabismus

26

Congenital causes of strabismus?

Congenital
- “normal” variation of brachycephalic

- Siamese cats - convergent, abnormal visual processing

- hydrocephalus— ventrolateral divergent, abnormal orbital volume

27

Acquired causes of strabismus?

Mechanical or nervous dysfutnion of any rectus muscle
CN III - dorsal, ventral, medial rectus m and ventral oblique
CN IV - dorsal oblique
CN VI - retractor bulbi and lateral rectus

Imbalance in orbital volume

28

What do you call an anterior displacement of the globe, such that the eyelids are caught behind the equator of the globe ?

What breed is this common in?

Proptosis

Brachycephalic breeds — involves minimal trauma

29

T/F: brachycephalic have a better prognosis after proptosis than dolichocephalic dogs

True

30

What features make a poor prognosis for proptosis?

Cats
Dolichocepalic
> 3 extraocular muscles torn
Ruptured eye
Hyphens orbital fractures

31

T/F: most dogs regain vision in the affected eye after proptosis

False

75-80% will be blind in the affected eye

32

Triage for proptosis?

Lubricate corneal
- triple antibiotic ointment or artificial tear ointment
- e collar
-minimize restraint
-pain managment, sedation or anesthesia

33

How is the eye put back into place after proptosis?

Horizontal mattress sutures in adjacent eyelids—> temporary toarsorrhaphy

Eye is pushed back into eye with dull end of scalpel blade,

Sutures tie lids together

+/-stents
-IV tubing
-red rubber catheters
-rubber bands

34

What maintenance therapy must you do following treatment of proptosis

Oral antibiotics for potential cellulitis/infection

If ulceration, give topical antibiotics and atropine

steroids or NSAID intra-op or post-op to reduce inflammation

Sutures stay in 3 weeks as cellulitis resolves

E collar!!

35

What are complications from treatment of proptosis?

Corneal ulceration — misplaced suture

Loosening of suture

Strabismus — Torn musculature

KCS

Blindness

Recurrence
Need for enucleation