Lids, Brows, Orbit, Lacrimal

telecanthus

increased distance between the medial canthi of the eyes

poliosis

whitening of lashes

what lies between skin layer and orbicularis layer

subcutaneous areolar layer of connective tissue

what happens when orbicularis muscle is paralyzed

ectropion of lower lid (due to riolan being paralyzed)

where does the superior palpebral levator muscle originate

lesser wing of sphenoid

what innervates the superior palpebral levator muscle

CN III

function of levator aponeurosis

attaches the superior palpebral levator to the upper lid

why does CN III palsy cause severe ptosis of upper lid

lack of CN III innervation to levator stops it from retracting lids

which glands are in the tarsal plate

M, W
meibomian glands, glands of Wolfring

what is found in epithelial layer of palpebral conj & what is their function

goblet cells (inferonasal fornix, bulbar conj)
produce mucin layer of the tear film

which glands are sebaceous glands

MGs & zeis

which glands are apocrine & what does it mean

moll & goblet cells
shed part of cell to be secreted

what type of motor innervation does muller muscle have

involuntary motor innervation (sympathetic system)

function of orbicularis in eyebrow movement

primary lateral depressor of the eyebrows

location of the lacrimal gland

lacrimal fossa of on the temporal side of the frontal bone (superior temporal lid)

what artery supplies lacrimal gland

lacrimal artery

what surrounds canaliculi and helps with tear drainage

muscle of horner

what lines the lacrimal sac and nasolacrimal duct

double epithelium, microvilli, and goblet cells

location and function of valve of hasner

end of nasolacrimal duct
prevents back flow of nasal fluid into lacrimal drainage system

two compartments of adipose tissue within EOMs

intraclonal: within the muscle cone of the recti
extraclonal: outside the muscle cone between EOMs and orbit

where in the eye do the EOMs attach

sclera

3 characteristics that differentiate EOMs from other skeletal muscles

EOMs have: denser blood supply, denser nerve supply, faster & more fatigue resistant movements

what is the LR anchored to

Whitnall's ligament

what is the MR anchored to

medial orbital septum

where does SO originate

lesser wing of sphenoid bone, and passes through trochlea

LR actions

primary: abduction

MR actions

primary: adduction

SR actions

primary: elevation
secondary: intorsion
tertiary: adduction

because of angle of insertion, SR & IR are responsible for ___________________ when eye is ________________ @ ______ degrees from the midline

pure depression or elevation, abducted, 23

what does the inferior CN III innervate

IR, IO, MR

functions of orbital fascia

provides support to BVs
serves as a point of attachment for muscles, tendons, and ligaments within the orbit

madarosis

loss of lashes

trichiasis

turning in of the lashes

phthiriasis palpebrarum

infection of lashes caused by Phthirus pubis (pubic lice)

what innervates the palpebral orbicularis oculi

CN VII
zygomatic branch of the facial nerve

what action is the orbital orbicularis oculi responsible for

forced closure of lids

what action is the palpebral orbicularis oculi responsible for

spontaneous actions and reflexive blinking

what 2 muscles are in the palpebral orbicularis oculi

muscle of riolan (pars ciliaris) & muscle of horner (pars lacrimalis)

function of muscle of riolan

riolan rotates ; roll, tide, divide
allows lashes to rotate towards eye during closure
keeps lid margin tightly against globe
most anterior portion is gray line, which divides lashes & MGs

ectropion

lower lid droops away from globe

function of muscle of horner

has fibers that encircle canaliculi and help drain tears into lacrimal sac

function of orbital septum

barrier of the orbit
prevents orbital fat from falling into lid
keeps infections localized to anterior lid and away from orbit

what part of the eye does the orbital septum not protect from infection & why

lacrimal sac
orbital septum attaches medially
lacrimal sac is located in front of attachment of septum

what structure separates preseptal cellulitis from orbital cellulitis

orbital septum
preseptal is in front of septum
orbital is behind septum

function of superior palpebral levator muscle

main retractor of eyelid

what ligament allows superior palpebral levator muscle to move and function

Whitnall's ligament

what does the superior palpebral levator become as it extends into the eyelid

levator aponeurosis tendon

what creates the superior & inferior palpebral furrow

superior: where levator aponeurosis attaches to lid
inferior: where inferior rectus muscle attaches to lid

what kind of muscle is muscle of muller

smooth muscle (a2 receptors)

what innervates muscle of muller

sympathetic nervous system

what is the function of the muscle of muller

minor retractor of lids

why does Horner's syndrome cause ptosis & reverse ptosis

lack of sympathetic innervation to Muller's stops it from retracting the upper and lower lids
(lack of retraction = ptosis)

is ptosis worse in Horner's or CN III palsy

CN III palsy
Horner's stops innervation to Muller, which is a minor retractor
CN III palsy stops innervation to levator, which is the main retraction

why does thyroid eye disease result in signature bulging eyes

TED causes increased sympathetic innervation, causing Muller's to retract lids more than it normally does

average interpalpebral fissure

10-12 mm

what nerve causes eye to open vs close

CN III causes eye to open (levator)
CN VII causes eye to close (orbicularis)

what is the tarsal plate composed of

connective tissue and collagen

function of tarsal plate

gives eyelids rigidity

2 layers of palpebral conj

epithelial & stroma (submucosa, substantia propria) layers

2 layers of stromal palpebral conj

superficial lymphoid layer
deep fibrous layer

function of superficial lymphoid layer of stromal palpebral conj

immunologically active layer with IgA, macrophages, mast cells, PMNs, eosinophils (protects conj from disease)

function & contents of deep fibrous layer of stromal palpebral conj

connects conj to underlying structures
houses accessory lacrimal glands of Krause

meibomian gland function & location

produces anterior lipid layer of tear film
tarsal plate

glands of zeis function & location

lubricate eyelashes
located at lash follicles

glands of moll location

near lid margin

glands of krause function and location

accessory lacrimal glands that secrete tears
located at fornices of the conj (fibrous layer of stromal palpebral conj)

glands of wolfring function and location

accessory lacrimal glands (less in # than krause)
located in tarsal conj

which glands are holocrine & what does it mean

MGs & zeis
shed entire cell to be secreted

which glands are merocrine & what does it mean

accessory lacrimal glands
don't shed any part of cell, secrete substances via exocytosis

what type of motor innervation does the orbicularis oculi have

voluntary motor innervation (zygomatic branch of CN VII)

what supplies sensory innervation to the upper and lower lids

CN V (trigeminal nerve)
upper: CN V1 (supraorbital & supratrochlear branches of frontal branch and lacrimal branch of ophthalmic nerve)
lower: CN V2 (infraorbital and zygomaticofacial branches of maxillary nerve)

what does the infratrochlear nerve innervate, and where does it come from

innervates medial aspect of upper and lower lids
comes from the nasociliary nerve that branches off of the ophthalmic nerve (CNV1 > nasociliary nerve > infratrochlear nerve)

path of arterial blood supply to deeper eyelid tissues

internal carotid artery > ophthalmic artery > lateral & medial palpebral arteries > deep eyelid blood supply
(lateral palpebral artery branches off of lacrimal artery)

2 branches of palpebral arcades and what they supply

marginal palpebral arcades: eyelid margin
peripheral palpebral arcades: fornices and posterior conj

what part of the lids do the external carotid branches supply

superficial eyelids

where do the anterior ciliary arteries supply blood

bulbar conj & ciliary body

why does uveitis cause circumlimbal injection and decreased aqueous production

the anterior ciliary arteries supply blood to the bulbar conj and ciliary body (where aqueous production occurs)

where do the eyelid veins drain

palpebral and ophthalmic veins

where are lymphatic vessels of the eyes found

conjunctiva

where do lateral lymphatics of the eye drain

parotid/preauricular lymph nodes (in front of ears)

where do medial lymphatics of the eye drain

submandibular lymph nodes (under jaw)

what ocular diseases can cause swollen preauricular lymph nodes

EKC!
chlamydial & gonococcal conjunctivitis, dacryadenitis

what ocular disease causes swelling of preauricular & submandicular lymph nodes

parinaud's oculoglandular syndrome

eyebrow function

protection & facial expression

what innervates the eyebrow muscles

CN VII

4 forehead muscles that create eyebrow movement

frontalis, corrugator, procerus, orbicularis

function & location of frontalis muscle

main eyebrow elevator
fibers run vertically on the scalp and insert into orbital rim

function & location of corrugator muscle

medial depressor of eyebrows
oblique fibers that pull brows down and in and produce vertical wrinkles on forehead, inserting into skin near medial brows

function & location of procerus muscle

medial depressor of eyebrows
pulls skin between the brows down and originates at nasal bone, giving horizontal wrinkes across bridge of nose

what divides the lacrimal gland into orbital and palpebral portion

tendon of levator aponeurosis

what kind of gland is the lacrimal gland & how does it release its products

tubuloalveolar exocrine gland
releases products via merocrine secretion

what vein drains lacrimal gland

lacrimal vein

where are the only lymphatic vessels in the orbit located

lacrimal gland (drain to preauricular nodes)

what type of innervation does the lacrimal gland receive and what does lacrimal innervation result it

parasympathetic innervation
stimulation causes secretion of the aqueous layer of tears

what innervates the lacrimal gland

lacrimal nerve of the pterygopalatine ganglion of CN VII (facial nerve)

dacryoadenitis

inflammation (due to infection) of the lacrimal gland that can cause swelling in the upper lateral lid

what is the lacrimal papilla and what does it do

ring of connective tissue surrounding the lacrimal puncta that is responsible for keeping the lacrimal puncta open

path of nasolacrimal drainage

sup & inf lacrimal puncta > sup & inf canaliculi > common canaliculus > lacrimal sac > nasolacrimal duct > valve of hasner

what lines the canaliculi

stratified & pseudostratified epithelium

where is the lacrimal sac located

fossa (lacrimal crest) in the medial orbital wall between lacrimal and maxillary bone