Dz and Sz of orbit (Whitley) Flashcards
1
Q
Orbit
A
- Cavity that holds the eye
- pyramid shaped cavity
- apex towards back of head
- contains
- globe
- related muscles
- blood supply
- nerve supply
- fat
- Carnivores: incomplete orbit
- lateral ligament
- dorsolateral portion: dense collagenous orbital ligament
- from zygomatic process of frontal bone to
- frontal process of zygomatic bone
- Herbivores/pigs: complete bony orbit
2
Q
Orbital Contents
A
- Bones
- Globe and optic nerve
- EOM in fascial slings
- Periorbita from orbital septum to tarsal plate
- Masticatory and pterygoid muscles
- Salivary and lacrimal glands
- many species with zygomatic salivary gland in orbit
3
Q
Floor of orbit
A
- soft tissue
- susceptible to penetrating trauma through the roof of the mouth
4
Q
Extraocular muscles
A
- Rectus muscles
- lateral
- medial
- dorsal
- ventral
- Oblique muscles
- superior/dorsal oblique
- ventral oblique
- Retractor bulbi
5
Q
DX tests for orbital dz
A
- Symmetry, d/c
- palpation, retropulsion
- attempt to open mouth
- pain: usually abscess
- exophth w/o pain: more consistent w/ neoplasia/cystic mass
- complete ophthalmic exam
- U/S, rads, CT, MR
- dental rads
- FNA
- BX (U/S guided)
- surgical explore
6
Q
Posterior indentation of globe seen w/
A
- Indirect ophthalmoscopy (BIO)
- Ocular ultrasound
- Transoral approach to ultrasound of orbit
7
Q
Clinical signs of orbital dz
A
- Globe displacement
- Periorbital swelling
- facial deform
- vis. impairment
- Imp nasal flow
- Ocular/oral pain
- pain when chewing
- Strabismus
- Chemosis
- protrusion of TE
- Blepharoedema
- Exposure keratitis
8
Q
Proptosis
A
- eyelids become entrapped behind the equator of the globe
- cannot blink
- globe usually anteriorly displaced
- secondary to trauma
- some cases will require enucleation
- TX
- lubricate
- assess for other trauma
- clean eye: eye wash, saline and dilute betadine
- lateral canthotomy
- strabismus hook pulls eyelids over globe
- temporary tarsorrhaphy (suture lids closed over globe
- horizontal mattress superficial sutures
- E-Collar
9
Q
Proptosis prognosis
A
- depends on
- condition of globe
- extend of orbital trauma
- PLRs
- size of pupil
- number of ruptured extraocular muscles
- 3 or greater not great prog
- duration
10
Q
Proptosis
Complications
A
- Loss of globe
- blindness
- strabismus
- corneal ulcers
- keratitis
- KCS
11
Q
Favorable prognosis for proptosis
A
- Brachycephalic breeds
- Intact PLR normal fundus
- No hyphema
- Only 1 EOM ruptured
12
Q
Poor prognosis for Proptosis
A
- Cats
- Non-brachycephalic breeds
- Hyphema
- No visible pupil
- orbital fractures
- more than 3 EOM torn
- damage to optic nerve
13
Q
Post Proptosis Exoptropia
A
- Lateral strabismus
- medial rectus often the muscle that is torn
14
Q
Proptosis prevention
A
- Medial or lateral canthoplasty
15
Q
Inflammation
A
- Retrobulbar abscess
- tooth root abscess
- Orbital cellulitis
- Immune-mediated myositis
