high-yield facts Flashcards
Which muscle controls eye opening?
Muller’s muscle
- 3rd nerve
Which muscle controls eye closing?
Orbicularis oculi
- 7th nerve
Give features of Horner syndrome
ptosis, myosis, ipsilateral anhydrosis
Where does the orbital septum lie?
posterior to orbicularis oculi muscle
Where is inflammation located in orbital cellulitis?
posterior to septum
Where are tears produced?
lacrimal fossa
Where do tears drain?
lacrimal punctum
Which nerve is required for reflex tear production?
trigeminal
Which nerve tells brain that tears needed ?
5th nerve
Which nerve controls tear production?
7th nerve
Which type of conjunctiva lines
a) the inner surface of the eyelid?
b) eyeball?
a) palpebral
b) bulbar
Which type of conjunctiva is more vascular?
palpebral
What type of secretions are seen in viral conjunctivitis?
thick, watery
What type of secretions are seen in bacterial conjunctivitis?
yellow/green
Which type of conjunctivitis has a very red eye?
bacterial
Give the layers of the cornea
Epithelium Bowman's membrane Stroma Descement's membrane Endothelium
Which layer of the cornea maintains transparency?
endothelium
–> pumps fluid out of stroma
What attaches the lens to the ciliary body?
zonules
- dec in tension allows for near focusing
What makes up the uvea?
the iris, ciliary body and choroid
What is the role of the uvea?
- absorbing reflected light
- nutritional support to eye structures
How is aqueous humour produced?
produced by filtration of blood at the ciliary processes and active secretion
Describe the path of aqueous humour
flows from posterior to anterior chamber and drains into the canal of Schlemm and trabecular meshwork
What are cells in the aqueous and flare signs of?
Uveitis
What are the elements that make up accomodation reflex?
convergence, pupillary constriction and contraction of ciliary muscle
What does contraction of the ciliary muscle cause?
decreases tension on zonule fibres
When do we use accommodation?
looking at something up close
Which ocular muscles does the third nerve NOT control?
lateral rectus
superior oblique
Aneurysm in which vessel leaves the third nerve vulnerable?
posterior communicating artery
Which nerve supplies afferent arm of corneal reflex?
trigeminal
Which nerve supplies motor innervation to lateral rectus?
CNVI (abducens)
When can abducens nerve palsy occur?
Raised ICP
What arises from the common tendinous ring?
the rectus muscles
Why does optic neuritis cause pain on eye movements?
optic nerve sheath is attached to the common tendinous ring
Where are cones found in higher density?
over the fovea
What supplies blood to the outer layers of the retina?
choroid
Describe the venous drainage of the eye
the superior opthalmic vein leaves the eye via the superior orbital fissure and the vein then drains into the cavernous sinus
Which wall of the orbit is most vulnerable to blunt trauma?
inferior wall
Which structures pass through the supraorbital notch?
supraorbital nerve and vessels
