Ocular Anatomy: eyebrow + eyelashes

Where is the frontal

Where is the nasal

where is the lacrimal

where is the maximal

where is the zygomatic

What are the different fascia

Orbital, periorbita, orbital periosteum

What is fascia

lining of tissue

fascia attachment mechanism

attaches better on corner, more loose on surfaces of the skull.

Frontalis:

origin, insertion and innervation

origin: scalp

insertion: superior orbital rim

Innervates CN 7 Temporal Branch

Procerus:

origin, insertion and innervation

origin: nasal bone

insertion: medial side of frontalis

Innervates CN 7 Temporal Branch

Depressor supercilii

origin, insertion and innervation

origin: superior maxilla bone

insertion: dermis under medial brow

Innervates CN 7 Temporal Branch

corrugated supercilii

origin, insertion and innervation

origin: frontal bone

insertion: skin superior to medial eyebrow

Innervates CN 7 Temporal Branch

orbicularis occuli

origin, innervation

origin: medial bony orbit

Innervates CN 7 Temporal, zygomatic Branch

What is plapebrae

Eyelids

Function of plapebrae

movement of tears, protection, produce tears.

What is lagopahthalmos

non-functioning/ closing eyelids

results in improper tear drainage and corneal ulceration and inflammation

Tarsal portion

thin delicate part of eyelids that cover the orbit. sticks onto eyes

Orbit portion

Thicker fatty part of eyelids that is loosely attached to the eye. more protective

Palpebral sulcus

furrow/ depression that separates orbit and tarsal.

palpebral fissure

empty space where eyes go.

canthus

medial and lateral canthus. located on the corners of palpebral fissure.

plica semilunari

folds of conjunctiva that allow for temporal movement of eyes

caruncle

gland further in the corner of medial canthus.

lacrimal papilla

Elevation on both superior and inferior eyelid. Contains the puncta

puncta

drainage found on the papilla. divides the lid margins into lateral ciliary and nasal lacrimal.

Epicanthic

asian monolid.

covers the caruncle and plica semilunaris. Present in young children but goes away as nose develops.

what is cilia

eyelashes.

more cilia on upper lid, supplied with nerves and plays a role in sensory reflex.

What is madarosis

loss of eyelashes

what is poliosis

general name of white hairs due to lack of melanin. can be marker of potential disease.

what is trichiasis

misdirected growth of eyelashes.

What is meibomian gland

found in ciliary portion (more in superior)

what is the grey line

insertion of the obicularis oculi, between cilia and meibomian gland. Weak spot of the tissue (often entry for surgery)

what are the layers of the skin

epidermis, dermis, subcutaneous areolar.

Subcutaneous areolar

loose connective tissue containing fat and blood.

orbicularis oculi

cranial nerve 7 (temporal, zygomatic), surrounds palpebral fissure

What is blepharospasm

spasm of the orbicularis. response to pain not from lack of sleep and caffine.

orbital portion of orbicularis oculi

Origin, action, opposing muscle

origin: medial bony orbit

action: tightly closing eyes

Opposing muscle: frontalis

multiple insertion around the orbicularis oculi.

Palpebral portion of orbicularis oculi

origin: medial palpebral ligament

insertion: lateral palpebral ligament

action: closure of eye gently; involuntary blinking

Horner’s muscle (pars lacrimalis)

muscle that arises from the lacrimal fossa (hole in the skull). Section of the palpebral obicularis oculi

located medially to the palpebral portion

Canaliculi

tubes that receive tears from puncta.

Surperior and inferior meet to form the common canaliculus

Lacrimal sac

Receives tears. lives in the lacrimal fossa.

What is the function of the horner’s muscle

encircles canaliculi, and contraction helps move tears down the drainage system.

Riolan’s muscle (pars ciliaris)

located near lid margin posterior to cliia on both sides of meibomian pores. aka grey line

insertion: lateral palpebral ligament(blinking) & grey line (tone).

Function of Riolan’s muscle

insertion of obicularis oculi to the eyelid skin. holds lid margin close contact with the globe.

squeezes on meibomian gland and secretes gland secretion.

loss of muscle tone leads to sag.

Entropion

inversion of lid margin.

differs to trichiasis.

ectropion

eversion of lid margin. caused by loss of tone.

epiphora

overflow of tears

levator palpebrae

Origin

superior palpebral levator.

striated muscle

Origin: lesser wing of sphenoid bone. above and anterior to optic foramen.

levator sheath attaches to what?

sheath of the superior rectus muscle. Fascia sheath touch each other (focal adhesion).

coordinates movement between eyes and eyelids.

levator palpebrae

insertion, action

insertion: skin of superior eyelids and tarsal plate. has to pass between orbicularis oculi

action: elevates eyelid

levator palpebrae innervation

cranial nerve 3 (superior branch)

levator aponeurosis

tendinous fanning out of levator.

potential space

areas of subcutaneous areolar between muscles.

Eg. space between obicularis that levator aponuerosis enter through

pretarsal space

potential space inbetween tarsal plate and obicularis oculi where levator aponeurosis attaches anteriorly to the tarsal plate and goes through the obicularis oculi.

What bones make up the lacrimal fossa?

Anterior lacrimal crest (maxillary bone) and posterior lacrimal crest (lacrimal bone)

lacrimal gland

lacrimal gland surround superior palpebral levator aponeurosis. divided into tow lobes

Orbital and palpebral.

medial horns attachment

attaches near fronto lacrimal suture and medial palpebral ligament.

Lateral horn attachment.

attaches to zygomatic bone and palpebral ligament

Function of medial and lateral horn

firm attachment for smoother movement of eyelid.

What is ptosis

issue with the levator nerves causing drooping of eyelid

Degree of ptosis

Big droop indicated by bigger levator muscle

small droop indicated by smaller muller’s muscle

Muller’s muscle (superior tarsal muscle)

smooth muscle that originates from the levator and attaches to the superior tarsal plate.

contributes to involuntary lid elevation.

inferior tarsal muscle

origin and insertion

Origin: inferior extraocular muscle sheath

insertion: lower conjunctiva and inferior border of lower tarsal plate.

inferior tarsal muscle innervation

sympathetic

inferior aponeurosis

origin and insertion

similar to superior but inferior

Tarsal plate

dense connective tissue of uniform collagen fibrils

Function of tarsal plate

adds rigidity

Palpebral conjunctiva

lines inner surface of the eyelid

stroma tightly adherent to tarsal plate

contains goblet cells

mucocutaneous junction

epithelial transition between skin and conjunctiva.

from keratinized skin to unkeratinized epithelium.

meibomian gland

embedded in tarsal plate

duct that opens at eyelid margin

long branching acini (grape cluster)

Function of meibomian gland

produce sebum called meibum

type of holocrine gland

What is holocrine secretion

When the whole cell becomes what is secreted

meibum secretion

acinar cells are compressed by myoepithelial cells.

holocrine cells fill the cell, and are filled with sebaceous granules (gives a fuzzy appearance)

as cells exit the acinar cell they degenerate and decompose.

Chalazion

non-infection meibomian gland clogging

meibomian dysfunction

reduction in secretion due to thickened lipid secrition or keratinized ducts.

usually due to shift in hormones - older women are more susceptible

Zeis gland

histologically the same as meibomian glands (holocrine)

function as lubricating eyelashes and protection of eyes.

positioned little inferior, posterior of the cillia.

Glands of Moll

serous glands (aqueous secretion filled with proteins)

large lumen with cuboidal secretory cells and myoepithelium

what type of gland is gland of moll

apocrine gland

where are Glands of moll found?

ducts open anywhere along the ciliary margin.

External hordeolum

stye

infected zeis or moll gland

internal hordeolum

stye infection of meibomian gland

accessory lacrimal glands

gland of krause

• superior to the conjunctiva fornix

gland of wolfring

• anterior to palperbral conjunvtiva

orbital septum

thin but dense connective tissue associated with the eyelids

starts at the orbital margin

Protective function of the orbital septum

lays anterior to the lacrimal gland to protect it from external environment

lays posterior to the lacrimal duct to separate old tears from the eyes

attachement of orbital septum

lateral

• attaches to the bony orbital margin at the zygomatic bone

medial

• attaches to medial bony margin

orbital seuptum attachment

fuses at the tarsal plate.

interrupted by levator aponeurosis. fuses to create tight barrier

orbital septum with age

loss of integrity and elasticity.

fluid accumulation and loose tissue.

orbital septum ASIAN PEOPLE

orbital septum fuses further anterior causing natural droop

Function of Tear film

refractive index

nutrition

mechanical

antibacterial

immune response

structure of tear film

3 layers:

outer- lipis

middle- aqueous

inner- mucin

lipid layer of tear film

prevents evaporation of tears

produced by meibomian glands and zeis glands

aqueous layer tear film

produced by lacrimal gland and krause and wolfring accessory glands

function: transport tear components and moisture

inner layer: mucin tear film

produced by goblet cells and ocular surface cells

• soluble and transmembrane mucins

Function

• hydrophilic coating for cornea to reguate surface tension

lid wiper theory

thin band of palpebral conjunctiva makes contact with ocular surface

accessory lacrimal glands

wolfring and krause

secretes aquesous layer for basal secretion

merocrine glands

ducts also have secretions

lacrimal gland

secretes aqueous fluid for basal and reflex secretion

secretions from lacrimal glands

Merocrine

what does lacrimal gland consist of

central lumen

secretory cells

myoepithelium

Duct structure of lacrimal gland

many tubules connect into 12 main ducts

Tear film pathway

down by gravity

medial by capillary action