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UHCO Eyelids

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Eyelids first appear as 2 circular folds around
2 months into fetal development
Folds fuse together
2 1/2 months into fetal development
Keratinization of surface epithelial cells initiates what when?
seperation of lids at 5 months
complete seperation of lids occurs when?
by the eighth month of gestation
do the lids of snakes seperate
no they remain clear as embryonic tissue
the hairless area between the two eyebrows is known as
the glabella
?Muscles of the eyebrow for Bergmanson
2 1/2 month gestation
Function of Frontalis muscle
Raises the brow in expression of surprise
Orientation of frontalis
radially over the forehead
3 portions of Orbicularis oculi
orbital, palpebral, ciliary(muscle of Riolan)
muscle fibers of Orb. ocul. are organized how?
concentrically
function of Orb. ocul.
close the eyelids by a sphincter action, spreading tears and flushing away waste
function of Corrugator supercilii
pulls eyebrows together (frown)
function of Pyramidalis (procerus)
creates transverse furrows above your nose (a bad smell expression)
4 functions of eyelids
protection, tear production, spread of tears across cornea, drainage of tears
is there a horizontal motion during blinking?
yes, it sweeps the tears towards the puncta
6 structures of the eyelids
1.skin 2. subcutaneous layer 3. muscles 4. submuscular areolar layer 5. fibrous layer 6. palpebral conjunctiva
describe the cutaneous portion of your eyelid
very thin, elastic and fat free
what is the skin composed of (3)
epidermis, dermis and subcutaneous tissue
the outermost layer is composed of
keratinized epithelial layer and many non-keratinized layers of epithelial cells
6 cell types in the epidermis
epithelial cells, keratinocytes, melanocytes, Langerhans & merkel cells, and neurons
Which cell type is most numerous
keratinocytes
location of dermis in relation to epidermis
internal and adjacent
dermis is composed of
dense irregular collagenous tissue
subcutaneous layer is found _____ to the dermis
deep
name 3 appendages on the surface of the eyelid
fine hairs, sweat glands and pigment cells
the appendages on the surface originate from
epithelial downgrowths
how many rows of lashes and glands along lid margin
2
where the skin meets the conjunctiva (along tarsal glands)
mucocutaneous junction
Keratinization of surface epithelium does or does not include epithelial lining of tarsal gland orifice
Does
malignant tumors are 4x more likely in which lid
lower
what type of cancer is related to UV radiation exposure
Basal cell carcinoma
What's the most common form of cancer in the Southern states?
Skin cancer
Are benign growths more prominant in one lid vs the other
no, they are evenly distributed
striated, voluntary muscle of eyelid
Orbicularis oculi or Levator palpebrae superiorus
Most prominent muscle of the lid
Orbicularis oculi
Palpebral portion of Orb. ocul. arises from
the medial palpebral ligament
at the lateral angle the fibers of Orbicularis oculi meet at the ____ _____ ___
Lateral palpebral raphe
function of ciliary portion
helpful in keeping the lid margin tight to the globe
Innervates Orbicularis Oculi
CN VII
Paralysis of CN VII leads to this
Lag ophthalmus, a dry eye condition due to inability to close the eyelids
origination of Levator palpebrae superioris
it originates from the inferior surface of the lesser wing of the sphenoid bone
levator palp. sup. origination location in relation to optic canal
above and anterior to the optic canal
which muscle is only found in the upper lid
Levator Palpebrae superiorus
Function of Levator Palpebrae superiorus
raising the eyelid
When the Levator palp. sup. becomes tendinous it is called
apaneurosis of the levator.
Where does the Levator become tendinous
as it enters the lid
Where is the aponeurosis of the levator found
between the bundles of the orbicularis oculi.
Innervation of Levator
CN III
Paralysis of levator causes
Ptosis
Smooth muscle in the lid
Tarsal muscles
Has primary sympathetic innervation and is found in upper and lower lids
Tarsal muscles
it lines the levator internally
SuperiorTarsal muscle
Function of Tarsal muscle
aids in laction of the levator
which muscle is important for the wide eyed expression of fear
Tarsal muscles
Damage to Sympathetic innervation of sup. tarsal muscle causes
droopy lid
Loose connective tissue btwn muscular tissue and the tarsal plate
Submuscular areolar tissue
What type of tissue makes of the fibrous layer
it consists of dense fibrous tissue
function of Fibrous layer
gives firmness and shape to the eyelids
AKA Tarsal plate
Fibrous layer of eyelid
what allows the upper lid to be everted
well developed tarsal plate collagen (not as much in the lower lid)
Where are the tarsal glands located
within the tarsal plate
A sero-mucous membrane containing goblet cells
Palpebral conjunctiva
Goblet cells
Mucin (MUC 5AC) producing, unicellular holocrine glands that make up the inner layer of the tears.
when do tarsal glands develope
2 1/2 months gestation
it has little saccules leading to a central canal, which opens at the lid margin
Tarsal gland(s)
Modified sebaceous gland
Tarsal gland
Function of sebum
forms the surface of the tears and slows their evaporation
organized in a single row running vertically throught eyelid
Tarsal glands
How many tarsal glands in the upper and lower lids
30-40 in upper and 20-30 in lower
rich innervation of tarsal gland
majority parasympathetic with sympathetic and sensory sources contributing to a lesser extent
Derived from pterygopalatine ganglion
CN VII Parasympathetic fibers
Infection of the tarsal gland
internal hordeolum
sterile lesion caused by chronic inflammation of tarsal gland
Chalazion (sometimes independent of chronic inflammation= de novo)
Glands associated with cilia
Ciliary glands(Moll) & Seabaceous glands (Zeis)
Ciliary and sebaceous glands are located ____to the tarsal plate
anterior
primitive sweat glands observed around the eyelash follicle
Ciliary glands
look like circles on histological slides but are actually spirals
ciliary glands
infection of ciliary gland
external hordeolum (Sty)
Which hordeolum is painful as a general rule
external hordeolums
they are self-limiting and easily treatable
External hordeoulums
chalazions can occur in _____ ______ as well as tarsal glands
sebaceous glands
mucin combines with water to form
mucous
function of mucous from goblet cells
acts as a wetting agent and helps spread tears across the cornea.
where is palpebral accessory lacrimal gland found
in the peripheral aspect of the tarsal plate
structurally and functionally similar to the lacrimal gland
palpebral accessory lacrimal gland
produces a serous secretion
palpebral accessory lacrimal gland
complex ductal system
connects palpebral accessory lacrimal gland to the palpebral conjunctival surface
palpebral accessory lacrimal gland ducts are lined by
secretory cells
how many openings are there on the middle portion of the lid
more than 100 openings per mm^2
reported in older literature to occur along the palpebral surface
Crypts of Henle
May have been mistaken for openings of the palpebral accessory lacrimal gland
Crypts of Henle
possibly artificial wrinklings of the tissue resulting from fixation induced shrinkage of the specimen
Crypts of Henle
2 transverse arcades in eyelid
marginal and peripheral arterial arcades
which arcade is found near the lid margin
marginal arterial arcade
the peripheral arcades are ____in location to the marginal
superior
name 2 arterial supply systems of eyelid
Facial and orbital
arteries of Facial system
Facial, superficial temporal, and infraorbital Arteries
Arteries of Orbital system
Dorsal nasal, frontal, supraorbital, lacrimal
Facial system branches off of
external carotid artery
Orbital system branches of of
internal carotid artery
name 2 venous drainage systems of eyelid
superficial (pre-tarsal) and deep (post-tarsal)
name veins of superficial system and where they drain
Anterior facial V drains to internal jugular V and Superficial temporal V drains to external jugular V
Name Veins of Deep system and where they drain
Ophthalmic V drains to cavernous sinus and Deep facial V to pterygoid plexus then cavernous sinus.
Eye itself has no lymph but eyelid has 2 systems name them
Superficial (pre-tarsal) and Deep (post-tarsal)
Superficial lymph. system drains
skin and orbicularis
Deep Lymph system drains
regions of the tarsal plate and the conjunctiva
which way does lymp flow
inward towards the conjunctiva (opposite blood flow)
lymphatic vessels drain into ____ ____ laterally
Parotid nodes
Lymphatic vessels drain into the ____ ____ medially
Submandibular nodes
Motor innervation of Eyelids
CN VII (voluntary) and CN III
CN VII innervates
all striated facial muscles except for levator
superior division of CN III innervates
levator
provides excitatory innervation of smooth tarsal muscles and gland
Sympathetic NS
Pre-ganglionic fibers of symp. NS are found
Lateral horn, Spine
Post-ganglionic fibers of symp. NS are found
superior cervical ganglion
provides inhibitory innervation to tarsal muscles and primary innervation to tarsal gland
Parasympathetic NS
Location of parasym. preganglionic neurons
superior salivatory nucleus of CN VII motor nucleus
location of parasymp. postganglionic neurons
pterygopalatine ganglion
Sensory innervation of lid is from
CN V
V1 innervates
upper lid (supraorbital N)
V2 innervates
lower lid (Infraorbital N)