Anatomy Flashcards
Telecanthus
An abnormal large distance between the medical acanthi of the lids
Poliosis
whitening of the eyelashes
Madrosis
Eyelashes falling out
Trichiasis
Turning inward of the lashes
Pthiriasis Palpebrarum
An infection of the lashes caused by pthiriasis pubis
Why is the skin layer of the eyelid unique
It is the thinnest in the body and contains no fat
Which layer is below the skin layer of the eyelid
Subcutaneous areolar layer. Contains the elevator aponeurosis
Orbicularis Layer
CN VII. Closes the eye.
Orbital portion or orbicularis
Attaches to the orbital margins and extends outward. used in force closure
Palpebral portion of orbicularis
Used for spontaneous and reflex blinking. Made up of muscle of riolan and muscles of horners
Muscles of Riolan
Pars ciliaris. Most superficial orbicular oculi. Keeps lid margin tightly applied to the globe. May rotate the eyelash inward with eyelid closure.
Gray line
Most anterior portion of the muscle of Riolan. Between the eyelashes and the meiobomian glands.
Muscle of Horners
Pars lacrimalis. Encircle the canaliculi and help drain tears into the lacrimal sac.
Submuscualar areolar layer
Between the orcicularis and the orbital septum. Contains the elevator aponeuris, palpebral portion of main lacrimal gland, and the peripheral and marginal arcades.
orbital Septum
Dense irregular connective tissue that serves as a barrier to the orbit. Prevents fat from falling down and keeps infections out.
Periorbita
covers the orbital bones. Projects anteriorly to become the orbital septum and posteriorly to fuse the dura of the ON head.
Where does the orbital septum attach
Medially to the posterior lacrimal crest (i.e. behind the lacrimal sac)
What inserts in the superior orbital septum
levator aponeurosis
Posterior muscular system
mullers muscle and Levator.
Superior palpebral levator orgin
lesser wing of the sphenoid
How much does it retract the lid?
15 mm
Whitnall’s ligament
Changes the direction of the Levator and allows it to perform its function.
Levator aponeurosis
A fan of the elevator in the eyelid.
Superior palpebral furrow
Formed by the elevator aponeurosis sending fibers through the tarsal plate to insert in skin.
Lateral horn of elevator aponeurosis
Travels across lacrimal gland and attaches to whitenall’s ligament.
Medical horn of levator aponeurosis
Travels medical to medial palpebral ligament
Inferior palpebral furrow
formed by indirect attachment of the IR into the skin of the lower eyelid.
Muscle of Muller
Innervated by alpha 2 of SNS. Originates from elevator and extends to the tarsal plate.
How much does muscle of muller widen eyelid
1-3 mm (minor)
Inferior tarsal msucle
original from fascial sheath of the IR and extends into the tarsal plate.
Normal interpalpebral distance in adults
10-12 mm
Tarsal Plate
Dense irregular CT that provides rigidity to the eyelids. Surrounds the meiobomian glands.
What do the tarsal plates become?
The medial and lateral palpebral ligaments.
Where does the medial palpebral ligament attach?
maxillary bone
Where does the lateral palpebral ligament attach
Whitnall’s ligament (also where lateral horn of Levator aponeurosis)
Layers of palpebral conjunctiva
Epithelial and stroma layer
Epithelial layer of the palpebral conjunctiva
Extends into the fornices and bulbar conj. Contains the goblet cells that produce the mucin layer of the tears.
where are goblet cells most commonly found
infernasal fornix and on bulbar conj temporally
Layers of Stroma of the palpebral conj.
Made up of superficial lymphoid layer and deep fibrous layer
Superficial lymphoid layer of the palpebral conj
Very immunologically active. Has IGA, macrophages, mast cells, PMNs, eosinophils.
Deep fibrous layer of palpebral conj.
Connects the conjunctiva to to underlying structures. Contains the accessory lacrimal glands, nerves, blood vessels of the eyelids. Becomes continuous with tarsal plate.
How many meiobomian glands are there
25 on top and 20 on lower
What do meiobomian glands produce and what kind are they
The lipid layer of the ear film. Holocene (whole cell shed)
Glands of Zeiss. What kind?
Lubricate the eyelashes. Also help with lipid layer. Holocrine.
Glands of Moll
Empty contents into lashes, glands of zeiss, and lid margin. Also help with lipid layer. Apocrine.
Glands of Krause
Accessory lacrimal glands. Mesocrine. Located in fornices of the conjunctiva (krause in creases).
Glands of Wolfring
Accessory lacrimal glands. Mesocrine. Larger and less numbers. In Tarsal conjunctiva.
Holocrine glands
Meiobomian and Zeiss. Secrete entire cell.
Apocrine
Moll and Goblet. A portion of plasma membrane buds off.
Mesocrine
Accessory lacrimal glands. Secrete by exocytosis.
What branch of CN VII controls the lid
Zygomatic controls orbicularis oculi
Involuntary motor innervation of the lid
Muscle of Muller controlled by SNS
Sensory innervation of the lid
Upper eyelid innervated by frontal and lacrimal branches of V1. Lower eyelid innervated by infraorbital and zygomaticofacial branch of V2.
Which innervation supplies both upper and lower lid senstation
infratrochlear branch of nasociliary from V1.
Branches of V1
Nasociliary, Frontal, Lacrimal
Nasociliary Branches
infratrochlear, anterior ethmoid, posterior ethmoid, long ciliary, short ciliary.
Branches of frontal nerve
Supratrochlear and Supraorbital
Branches of V2
Infraorbital and zygomaticofacial.
What layer are the palpebral arcades located in
Submuscular areolar layer
What forms the palpebral arcades
Medial palpebral artery (from ophthalmic artery or dorsal nasal artery) and lateral palpebral artery (from the lacrimal artery)
Marginal palpebral arcades
near the eyelid margin
Peripheral palpebral arcades
Supply the fornices and the posterior conjunctiva. Connect with anterior ciliary arteries which supplies the anterior conj.
What do Anterior ciliary arteries provide
Provides circulation to the bulbar conj. and the CB. Why a patient with uveitis can have circumlibal injection.
What external artery branch provides the lids
The facial artery
Where do lateral lymphatics drain
Parotid (pre auricular) lymph nodes
Where do medial lymphatics drain
submanidubular lymph nodes
What is the only type of bacterial conjunctivitis that presents with parotid lymphadenopathy swelling?
Gonococcal conjunctivitis
What commonly results in pre auricular lymphadenopathy
viral infections. (viral conjunctivitis, chlamydia conjunctiviies, and dacryoadentitis)
Frontalis
The main elevator of the brows. Originates high on the scalp and inserts near the Superior orbital rim
Corrugator
Concentration or sorrow. Medial depressor of the eyelids. Originates at frontal bone and inserts in skin above medial eyebrows.
Procerus
Agression. Pull the skin between the eyebrows downward. Originates at nasal bone and inserts on the frontal.
What divides the lacrimal gland?
The superior palpebral elevator tendon
How does the lacrimal gland receive parasympathetic innervation
From the lacrimal nerve of the pterygopalantine ganglion of CN VII.
How does the lacrimal gland receive sympathetic innervation
SNS follows the lacrimal artery to innervate the gland.
Acute dacryoadentitis
inflammation of the lacrimal gland. S shaped.
What is responsible for keeping the lacrimal puncta open
Lacrimal papilla
Cannaliculi
10mm long. Connects the punch to the lacrimal sac. Runs 2mm vertical and then 8mm medially to join the common canaliculus that joins into the lacrimal sac.
What does the muscle of Horners do?
During eyelid closure it contracts and assists with tear draining.
What bones form the lacrimal fossa
Lacrimal bone and maxillary bone.
How long is the lacrimal sac
10-12 mm
What tendon straddles the lacrimal sac
Medal palpebral ligament (from the tarsal plates)
Darcyocystitis
Infection of the lacrimal sac.
What sinus does the nasolacrimal duct lay adjacent to
maxillary sinus.
How long is the nasolacrimal duct?
15 mm
Where does the nasolacrimal duct terminate
inferior meatus
Valve of hasner
At the end of the nasolacrimal duct. Stops back flow
Intraconal Adipose Tissue
Within the cone. Separates ON from the EOMs
Extraconal adipose tissue
outside of the cone. Between the EOMs and wall of orbit.
The Sheath of the _____ and _____ are connected
SR and elevator. Allow lids to go up with upward movement.
Spiral of Tillaux
The insertion of the rectus muscles. Medial is closest, then inferior, then lateral, then superior.
MR insertion
5.5 mm
IR inserteion
6.5 mm
LR insertion
6.9 mm
SR insertion
7.7 mm
Where do all recti muscle originate
CTR
SO origin
Lesser wing of sphenoid and CTR.
Physiological origin of SO
trochlea
IO origin
Only muscle to originate anteriorly. Originates from the maxillary bone.
Muscular artery branches
Superior lateral and inferior medial
Superior lateral artery supplies…
SR, SO, LR.
Inferior medal artery supplies
IR, IO, MR.
Superior division of the CN III supplies what…
SR.
Inferior division of the CN III supplies what…
MR, IR, IO.
What creates the orbital septusm
Orbital fascia
What is in lesser wing
Optic canal, elevator starts, So starts
Great wing forms the
Lateral wall
Foramen within greater wing
Formen rotundum (v2), formane ovale (v3), formane spinosum (middle meningeal artery)
Where is the SOF
between the greater and lesser wing.
Annulus of Zinn
Common tendinous ring. Orgin of the Rectus muscles
What goes through the CTR and SOF
Nasociliarty of V1 (along with sympathetic root), oculomotor nerve, Abducens nerve.
What goes through SOF but above the CTR
Superior ophthalmic vein, frontal nerve, lacrimal nerve, trochlear nerve. SOV, FLighT.
What goes through IOF and below CTR
inferior ophthalmic vein and occasionally central retinal vein if it hasn’t joined ophthalmic vein)
what goes through carotid canal
Internal carotid artery and Sympathetic plexus
what goes through Supraorbital formaen
supraorbital n. (V1) and vessels
what goes through Infraorbital formaen
infraorbital n. (v2) and vessels
what goes through sylomastoid formen
facial nerve
mnemonic for bones that make up the orbit
Many Friendly Zebras Enjoy Lazy Summer Picknicks
What makes up the roof of the orbit
Front-less. The lacrimal gland is in a fossa in the frontal bone
What makes up the floor of the orbit
My Pal gets His Z’s on the floor. Maxillary, palatine, Zygomatic.
what makes up the medial wall
SMEL. Body of sphenoid, Maxillary, ethmoid, lacrimal.
Lamina Papyracea
Orbital portion of the ethmoid. Very thin. Infectious of sinus can spread
Lateral wall
Great Z. Great wing of sphenoid and zygomatic.
Which wall does not have sphenoid
inferior
cavernous hemiagnomas
most common benign orbital tumors in adults
capillary hemangionomas
most common being orbital tumors in kids
Important branches of the external carotid artery
Facial artery, superficial temporal artery, and maxillary artery.
Angular artery
Terminal branch of the facial artery that supplies medical canthus with the dorsal nasal artery (from ophthalmic artery)
Maxillary artery
A terminal branch of external carotid artery. Gives of infraorbital artery that supplies IR and IO and exits orbit and supplies the lower eye lid and lacrimal sac before joining with the angular artery and the dorsal nasal artery
Anastomose of the lacrimal sac
infraorbital (ECA), angular (ECA), and dorsal nasal (ICA). DAI.
Superficial temporal artery
Branches Ant temporal, zygomatic, transverse.
Which nerve travels closest to the ICA
CN VI
Where does the ophthalmic a. branch from
Internal carotid
Branches of the ophthalmic artery
CRA, Lacrimal A, Muscular, SPCA, LPCA, Supraorbital, Ethmoid. –>Supratrochlear and Dorsonasal.
Lacrimal artery branches
Travels along the lateral wall and supplies the lr and lacrimal gland. It terminates as the lateral palpebral artery for lacrimal arcades.
Muscular artery
Superior lateral: SO, SR, LR. Inferior Medial: IO, IR, MR
What lawyers are the CRA in
NFL and ONL/OPL
Anterior ciliary artery
formed by branches of the muscular arteries. Combines with LPCA to form MACI
Short Posterior Ciliary Artery
Forms the circle of Zinn to supply optic nerve, posterior choroid, and macula.
Long Posterior Ciliary Artery
Travel between sclera and choroid. Provide the anterior choroid before forming MACI.
What makes up MACI
Anterior ciliary arteries (from muscular branches) and LPCA.
Supraorbital artery
Provides SR, SO, elevator before going through Supraorbital notch to supply the scalp.
Ethmoid artery
Branches supply the sphenoid, frontal, and ethmoid sinuses.
Supratrochlear artery
Terminal branch of ICA. Supplies the forehead, scalp, and muscles of forehead
Dorsal nasal artery
Supplies lacrimal sac and then joins angular (facial-ECA)
Medial palpebral artery
branch of dorsal nasal that form palpebral arcades.
What causes ocular ischemic syndrome?
Occlusion of ICA or ophthalmic artery.
Central Retinal Vein
Drains blood from the inner 6 layers of the retina that are supplied by the CRA. Exits through the optic nerve and then enters the cavernous sinus, either directly or joining with superior ophthalmic veins first.
Anterior Ciliary Veins
Drain the anterior structures. Drain into the superior and inferior ophthalmic veins.
Vortex veins
Drains blood from the choroid. Drain into the superior and inferior ophthalmic veins.
Superior Ophthalmic Veins
Drains the majority of the eye (muscular=MR and SR) Formed by angular artery (formed by supraorbital and facial). Exits through the SOF and then joins the cavernous sinus.
Inferior ophthalmic veins
Drains muscular (MR, LR, IO, IR). Divides into superior and inferior branch
Superior branch of inferior ophthalmic vein
Exits through SOF and then drains directly to cavernous sinus or joins with SOV
Inferior branch of inferior ophthalmic vein
Exits through IOF and then drains into ptyergopoid plexus to communicate with facial veins
Supraorbital vein
Combines with the facial v. to form angular v. –>SOV
Angular vein
Becomes the anterior facial vein. Gets blood from pterygoid venous plexus and superior and inferior palpebral veins. Joins with posterior facial vein to form the common facial vein. Common facial vein drains into internal jugular vin.
Infraorbital vein
drains the lower face and then drains into the pterygoid plexus
Ptergoid venous plexus
The anterior facial vein (from angular), Inferior branch of IOV, and infraorbital all drain into it. Communicates with cavernous sinus with orbital veins and emissary veins of the cranium.
What does the venous plexus form?
The maxillary vein
Superficial temporal vein
Joins the maxillary vein within the parotid gland to form the posterior facial vein (combines with anterior facial to form form common facial).
Middle temporal vein
Drains into the superficial temporal vein. Receives blood from the orbital vein that originates from lateral palpebral venous branches.
Posterior Facial vein
Formed by superficial temporal vein and maxillary vein. Divides into an anterior and posterior branch
Anterior branch of posterior facial vein
Joins with anterior facial vein to form common facial v. then drains into internal jugular vein.
Posterior branch of posterior facial vein
Joins with the posterior auricle vein to form the external jugular vein
Occipital vein
Can drain directly to the internal jugular vein or join the posterior auricle to drain into the external jugular vein
External jugular vein
Formed by union of posterior facial vein (retromandibular vein) and the posterior auricular vein and drains blood from the superficial face.
Internal jugular vein
Continuation of the sigmoid sinus and drains the common facial, occipital, lingual, and superior and medical thyroid veins.
What travels through the Cavernous Sinus
V1, V2, III, IV, VI, ICA, post ganglionic sympathetic fibers that travel around ICA, and parasympathetic fibers around CN III
What does not go through the cancerous sinus
V3, CN VII (and parasympathetic fibers that travel with CN VIII)
Tolosa Hunt Syndrome
Inflammation of SOF or Cavernous sinus. Has painful external othamolpegia and diplopia.
Carotid Cavernous Fistula
Abnormal communication between the arterial and venous blood supplies in the cavernous sinus. Associated with painful red eye, ocular bruit, and pulsatile proptosis.
Superior Petrosal Sinus
Drains the inferior cerebral and some cerebellar veins. Communicates with cavernous sinus and transverse sinus.
Inferior Petrosal sinus
From the posterior inferior cavernous sinus. Exits through the jugular foramen and drains into internal jugular vein
Superior Saggital sinus
Located in the falx cerebra. Drains into the right transverse sinus.
Inferior saggital sinus
in the inferior fall cerebri. Forms the straight sinus.
Straight sinus
Originates at the junction of the falx cerebra and tentorium. Drains into the left transverse sinus.
Occipital sinus
Drains into the left transverse sinus.
Transverse sinus
Form the sigmoid sinuses.
Sigmoid sinus
Exits and becomes the internal jugular vein.
Confluence of the Sinuses
Metting point of Superior sagittal, straight, occipital, and transverse sinus. Located on the internal occipital protuberance. SS TOS.
Average axial length
24 mm
Why is the cornea able to refract so well?
The large difference in n values between the air and tears.
Where is the cornea thicker?
The periphery.
Central radius of curvature for the front of the cornea
7.8 mm
Central radius of curvature for the back of the cornea
6.5 mm (steeper)
Diameter of anterior
Horizontal=11.7 Vertical=10.6
Diameter of posterior
11.7 horizontal and vertical
What has type 4 collagen in the cornea?
BM and descemts.
What forms the epithelium
surface ectoderm.
Surface layer of the corneal epithelium
2 layers of non-keratizinzed squamous cells. Plasma membrane secretes a glycocalyx and contains micropillae and microvillae.
What is the only layer in the cornea to have ZO
epithelium surface layer
Wing cells
2-3 layers going by desmosomes
Basal layer of epithelium
Only mitotic layer in corneal epithelium. Made up of 1 layer of columnar cells. Basal layer secretes basement membrane. Attaches to basal layer by hemidesmosomes.
Increased chances of RCE
- poor hemidesomes attachment 2. EMD 3. age related thickening of cornea
Palisades of Vogt
Where all stem cells of epithelium are. 1 mm band at the layer of the basal.
Is bowman’s layer a BM?
NO
What type of collagen is Bowman’s made up of
Type 1. Bones and sclera too.
What makes bowman’s layer
Prenatally by anterior stroma.
What function may bowman play
Maintaining the curvature of the cornea
Band Keratopathy
Calcium deposits within bowman’s layer (swiss cheese)
Crocodile Shagreen
Gray-white polygonal stroll opacities that may involve bowman’s layer
Keratocytes of the stroma
Fibroblasts the produce collagen fibrils and the extracellular matrix
Collagen fibrils of the stroma
Uniformly spaced lamellae.
The anterior 1/3 of the storm has a ______ incidence of cross linking
Greater
The posterior 2/3 of the storma is _______ organized and has less uniformly lamellae and ____ cross linking
more, more
The less cross linking with the posterior stroma results in
higher incidence of corneal edema
What is the GAG in the cornea?
Keratin Sulfate
What produces Decesments?
The corneal endothelium.
What type of collagen is descements?
Type 4
Schwalbe’s line
The ending of descents at the limbus
Hydrops
Occurs in keratoconus as a results of rupture of descements
Haab’s striae
Folds in descements with congenital glaucoma
Hassal-Henle bodies
small ares of thickened descent’s in the corneal periphery. Increase in number with age and have no visual significance.
Endothelium of the cornea
Squamous cells with NA/K ATP pumps that maintain corneal hydration and transparency.
Where does cornea obtain nutrients?
Aqueous humor, Limbal conj and episcleral capillary networks, and palpebral conj. vessels.
Main source of O2 in the open eye
tear film
Main source of O2 in the closed eye
Palpebral conjunctival blood vessels.
What is corneal innervation responsible for
wound healing and pain sensation
Where do LPCN’s enter cornea?
The midstroma. After traveling 2-4 mm inside stroma, the corneal nerves lose their myelin sheath as they penetrate bowman and are now nocireceptors.
Where are there no nerves in the cornea
Endo, descemets, posterior stroma.
Stratified non-keratizined layer of conjunctiva?
Made of cuboidal/columnar cells in palpebral and squamous in the bulbar conj. Superficial cells have melamine granules, microvilli, and goblet cells.