Orbit, Eyes, and Lacrimal System Flashcards Preview

Neuro 3 (mine) > Orbit, Eyes, and Lacrimal System > Flashcards

Flashcards in Orbit, Eyes, and Lacrimal System Deck (26)
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1
Q

Orbit floor

A

PaM-Z: palatine, maxillary, zygomatic

  • Clinically WEAKEST
  • hypoethesia due to infraoribtal nerve trauma
2
Q

Medial wall of orbit

A

-SMEL
sphenoid (lesser wing), maxillary, ethmoid, lacrimal
-thinnest
-lacrimal sac fossa
-optic foramen
-inferior oblique muscle arising from lacrimal crest

3
Q

Orbital roof:

A

frontal, lesser wing of sphenoid

4
Q

Lateral wall

A

Great-Z: greater wing of sphenoid, zygomatic

-THICKEST wall

5
Q

Extraocular muscles

A

4 rectus muscles, 2 oblique muscles

inferior oblique is the only one that doesn’t arise from back portion of the globe

6
Q

Neurovasculature

A
cranial nerves (oculomotor does most; lateral rectus from abducents, superior oblique from trochlear)
optic nerve, ophthalmic artery and vein
7
Q

Sensory innervation

A
CN V (trigeminal)
Ophthalmic division (V1): nasociliary, frontal (supraorbital, supratrochlear), lacrimal nerves

Maxially division (V2): infraorbital (cheek numbness w/ damage), zygomatic

8
Q

Oculocardiac reflex

A

Increased pressure on eye, pulling on eye muscles–>bradycardia, asystole, arrhythmia

afferent: CN V1 (ciliary ganglion to trigeminal)
efferent: CN X

Treatment:

  • release globe/muscle
  • atropine
  • glycopyrrolate
  • preventative (or provoking): retrobulbar/peribulbar block
9
Q

Orbital fractures

A

-floor and medial wall most commonly affected -Most often occurs medial to infraorbital canal–>leads to hypesthesia in cheek and upper lip (V2)

Repair in w/in 2-4 weeks if:

  • enophthalmos (eye sunken in because of volume in orbit decreased)
  • incarcerated muscle/orbital tissue
  • > 50% of wall fractured
10
Q

Orbital cellulitis

A
  • presents with pain, erythematous lid swelling, TTP
  • EOM restriction, proptosis
  • Later: vision loss, RAPD, decreased color vision, increased IOP
  • Mgmt: broad spectrum antibiotics, CT orbits with contrast, abscess I/D
11
Q

Layers of eyelid below lid crease

A

Skin
orbicularis muscle
tarsus (Meibomian glands inside)
conjunctiva

12
Q

Layers of upper eyelid above crease

A
skin
orbicularis muscle
septum
fat
levator aponeurosis
Muller's muscle 
conjunctiva
13
Q

cavernous sinus thrombosis

A
  • sequelae of uncontrolled orbital cellulitis/facial cellulitis
  • Orbital veins are valveless: retrograde spread of infections to cavernous sinus
  • CN III, IV, V1, V2, VI palsies, proptosis, chemosis, altered mental status
  • may have permanent neuropathies; death from sepsis
14
Q

Layers of lower eyelid below crease

A
skin
orbicularis
septum
fat
LL retractors (CPF)
Muller's muscle
conjunctiva
15
Q

Arterial supply

A

superior/inferior marginal arcades (2mm from margin)

Superior peripheral arcade (between levator and Muller’s)

16
Q

Preseptal cellulitis

A
  • In front of septum
  • Can open/move eye
  • No involvement of orbit
  • Oral Abx, drain pus
17
Q

Chalazion

A
  • plugged Meibomian glands within tarsus cause inspissation of meibum (oil)
  • treatment: warm compress
18
Q

Eyelid trauma

A

if fat protruding through, septum has been violated

-Posterior to that is levator aponeurosis, if damaged could lead to ptosis

19
Q

avulsion

A

-torn eyelid, need to repair levator

20
Q

Principles of eyelid repair

A
  • anterior vs posterior lamella
  • fat visible: check levator
  • eyelid margin involvement
  • Canalicular involvement (tear drainage system)
21
Q

Repair algorithm for eye damage

A

Reconnect levator aponeurosis to tarsus
-reappose tarsus
-reappose eyelid margins
reappose skin and orbicularis

22
Q

Where is lacrimal sac?

A

below median canthal tendon

23
Q

tear production

A

lacrimal and accessory glands

Lacrimal gland:
two lobes
ducts from both lobes pass thru palpebral lobe to enter conjunctiva
-symp, parasymp, sensory nerves innervate orbital lobe
-bg to func at 6 weeks

Accessory glands:
-Krause
-Moll
-Zeis
?wolfring, meibomian?

No lacrimal gland? dry eye but accessory glands help with tearing.

24
Q

tear drainage

A

lacrimal punta, canaliculi, lacrimal sac, duct

25
Q

Dacryocystitis

A

Infection of lacrimal sac due to nasolacrimal duct obstruction

  • treat w/ abx
  • when infection resolved, treat with surgical bypass (dacryocystorhinostomy)
26
Q

Adenoid Cystic carcinoma

A
  • MC malignant LG tumor
  • perinueral invasion (pain), bone destruction, rapid spread (months)
  • death from intracranial extension/mets (80% mort at ten years)
  • Treatment: rad, chemo, exenteration, targeted chemo with exent/XRT

Also take out orbit with lacrimal gland so can’t spread.