Orbit Flashcards
The _____coverint the eyelid is very thin and continuous with the palpebral conjunctiva
skin
sparse, loose conective tissue that rarely contains fat in the eye
subucatneous tissue
ciliary glands are found in what laere of the eyelid
subcutaneous tissue
ciliar glands are
mixed sebaceous and modifies sweat glands
Zeis glands
sebaceous
Moll glands
modified sweat
if the sebaceous and modifies sweat glands of the eyelid become infected, what forms
a sty
Orbicularis occuli has two portions
palpebral potion and lacrimal portion.
palpebral - integrated with levitator palpebrae superiors
lacrimal - extends from posterior lacrimal crest to the tarsal plates of lids and lacrimal sac, increases the amount of lid contact to the suface of the eyeball
levator palpebrae superioris muscle inserts
into palpebral fascia and skin of upper lid
levator palpebrae euperioris innervated by
GVE fibers of oculomotor nerve (III)
destruction of the oculomotor nerve or one of its branches to levitator palpebrae superiorisresults in
paralysis of this muscle and COMPLETE ptosis
This is ocular nerve palsy
Ocular nerve palsy
complete ptosis, external strabismus, pupillary dilation
tarsal muscle of Muller inserts on
tarsal plate of the upper lid
tarsal muscle innervated by
postganglioinc sympathetic fibers
tarsal muscle affected in what syndrome
horner;s syndrome
cartilagineous plate tied in with the orbital septum
tarsus
Horner’s syndrome involves
paralysis of the tarsal muscle, concomitant SLIGHT ptosis an dmiosis.
enophthalaus and anhidrosis and blushing
the retina is an invagination of
diencephalon
othe ___ formas a firewall between deep and superficial contents of the orbit
orbital septeum
why is the orbital septum important
because the orbit is very closely related to the brain
when we suffer traumatic facial injure what do we care about repairing first
want to line up the teeth and the orbit
Palpebral fascia is composed of
tarsus and orbital septum
What do the tarsal glands secrete, and why is ti important
an oily secretion which helps to resist the overflow of tears at the palpebral margin
tarsus
comprised of two dense fibrous connective tissue plates in the upper and lower margins of the lids.
both are attached to the medial and lateral palpebral ligaments, and are semilunar shaped in order to conform the curvature of the eyeball
what happens if you throw off the margin of the eyelids
like when you mess up your windshield wipers. lids no longer uniformly moving across the surface of the eye
Continuous with periosteum at the superior and inferior orbital margins, attached to tarsal plates,
orbital septum
superior palpebral fascia is pierced by
levator palpebrae superioris m
Conjunctiva
thin membrane that lines the back of the eyelids (palpebral)and front of the eyeball (bulbar)
palpebral conjunctiva
is opaque and highly vascular membrane. covers posterior surface of lids,
bulbar conjunctiva is
transparent membrane loosely attached to the eyeball.
semilunar fold
crescent shaped membranous fold formed by the bulbar conjunctiva t the MEDIAL can thus. forms the lateral border of the triangularly shaped lacrimal lake at the center of which is the lacrimal carunck
why can’t swelling of the lid get from upper lid to lower lid on the medial side
because of the orbital septum at the medial side.
what gland produces tears to keep the surface of the cornea moist
lacrial gland
parasympathetic innervation of lacrimal gland
superior salivatory nucleus–> facial nerve–> freater superficial petrosal nerve and vidian nerve –> sphenopalatine ganglion
post ganglionic parasympathetic fivers course via maxillary, zygomatic and lacrimal nerves
Sumpathetic innervation of the lacrimal gland
post ganglionic sympathetic fibers from superior cervical ganglion, –> internal carotid plexus–> deep petrosal nerve, –> fuses with greater superficial petrosal to form vidian nerve–> through sphenopalatine ganglion and distribute to lacrimal gland via maillary zygomatic lacrimal nerve route.
may even reach it in lacrimal plexus in adventitia of lacrimal artery
lacrimal canaliculi
small L shaped tube located at the palpebral margins of each led at the medial canthus. The two canaliculi straddle the posterio aspect of the medial palpebral ligament
function of lacrimal canaliculi
drain tears from the surface of the eyeball to the superior lateral aspect to the lacrimal sac
lacrimal sac
elongated sac receives the lacrimal canaliculi and is continuous inferiorly with nasolacrimal duct
nasolacrimal duct courses through
nasolacrimal canal. and opens into inferior meatus 1cm posterior to the anterior edge of the inferior concha (drains into the nasal cavity)
Bony orbit comprised of what bones
frontal, zygomatic, maxilla, each are common points of fracture
supraorbital margin of orbit
frontal bone
supra orbital notch
lateral margin of orbit
zygomatic bone, associated with orbital tubercle, the point or attachment of lateral palpebral ligament
infraorbital margin
zygomatic and maxilla bones
infraorbital foramen at midpoint
margins are ____ than walls
thicker
herniation of orbital contents herniate where
maxillary sinus - here we are concerned with infection
fractures of the orbit can compress what structure
the optic nerve
Blow out fractures of the floor of the orit
may be due to trauma to the front of the eyeball or a depressed fracture of the zygomatic bone, which is displaced medially
cause herniation of certain orbital structures into maxillary sinus