Optic Flashcards
What bones make up the outer rim of the orbit?
frontal- superior roof
zygomatic- lateral
maxilla- medial and inferior/ largest part of floor
What makes up the inside of the orbit?
lacrimal
ethmoid
sphenoid
palatine
What are the base and apex of the orbit?
base- orbital margin
apex- optic canal
What happens if you get directly hit in the eye?
“blown out fracture”
maxillary sinus/floor can fall in
eye fall in
How do we keep our eyes straight ahead?
eyeball/ axis of orbit angled
What is the space between the upper and lower lids?
palpebral fissue
palpebral margins meet at canthi (angle)
eyes want to close at rest
What opens the eye lid?
aponeurosis of levator palpebrae superioris
no muscle for lower lid
What helps close lid>
orbicularis oculi
straight when contracted
What opens the eyes wide during flight or fight?
tarsal gland
sympathetic response
What are the 7 layers of the eyelid?
external to internal
skin subcutaneous connective tissue (fat) muscular layer submuscular layer tarsal plate tarsal glands palpebral conjuctiva
What protects and lubricates the eye?
superior and inferior palpebrae
What are involved in the eyelid?
musculocutaneous junction- where skin hits palpebral conjuctiva
palpebral conjuctiva- mucus memvrane on inside of eyelid
orbital conjuctiva- becomes continous with PC/ protective covering of eye
What causes Horner’s syndrome?
lesion to the superior cervical sympathetic ganglion
results in paraslysis of tarsal muscle on affected side
ptosis (drooping eye lid)
myosis (small pupil)
anhydrosis (lack of sweating and reddness of skin on affected side)
What are the edge corners of the eye?
medial and lateral canthus
What is the larger medial angle of the eye?
lacrimal lake
What fleshy elevation seen in the medial angle of the eye within the lacrimal lake tht contains sweat glands, sevbaceous glands, and cilia>
lacrimal caruncle
yellow and white secretion found when you wake up in the morning
What is the connective tissue that separates the sclera from the lacrimal lake found lateral to the lacrimal caruncle?
plica semilunaris
What is the third eyelid in other animals>
plica semilunaris
What is thee lacrimal punctum?
drain for the eye
Where does the lacrimal gland ducts drain>
superior palpebral fornix
What does the lacrimal gland secrete?
solution with baceriocidal enzyme lysozyme
provides nutrients and dissolved oxygen to cornea
Where do tears go?
collect in superior fornix of upper lid
pass over the eye surface
aided by blinking
How do tears drain?
puncta lacrimali- drain opening
lacrimal canaliculus- duct
lacrimal sac- collection fluid
nasolacrimal duct- drain to nasal sinus
What kind of nerves innervate the lacrimal gland?
parasympathetic CN VII
greater petrosal nerve branch
How is the lacrimal gland innervated?
greater petrosal nerve joins deep petrosal nerve (sympathetic) and forms nerve of pterygoid canal
runs through pterygoid canal
goes to pterygopalatine fossa to pterygopalatine ganglion
Which fibers synapse at the pterygopalatine ganglion?
parasympathetic fibers ONLY
What happens after parasympathetic fibers synapse?
rejoin with sympathetic fibers to join with maxillary nerve V3 and follow zygomaticotemporal branch anteriorly
join lacrimal branch of V2 to lacrimal gland
How do parasympathetic and sympathetic stimulation affect lacrimal secretion?
parasym- increase secretion/tearing
symp- vasoconstrution and decrease in tear production
What are the muslces of the orbit called?
extraocular muscles (6)
What are the recti muslces of the eye?
superior rectus
inferior rectus
medial rectus
lateral rectus
all originate from anulus tendineus ring around orbital fissure and optic canal
What orbit muscles do not orignate from anulus tendineus?
superior oblique
inferoir oblique
levator plapebrae superioris
What does superior oblique attach to?
facial sling = trochlea
Why is there a medial pull of superior and inferior rectus?
orbit directed in medial to lateral direction
How does the CNS reposition the eye?
The 6 extraocular muscles function at all times
changing tension moves quickly
How do the oblique muscles pull?
IO-UO, SO-DO
inf obl up and out
sup olb down and out
What are the two divisions of the CN III?
superior and inferior
What does the superior diviion of CNIII innervate?
levator palpebrae superior and supieror rectus
What does the inferior division of CNIII innervate?
medial and inferior rectus and inferior obique
carries parasympathetic fibers to ciliary ganglion