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.
Submucosa of the Conj.
Outer lymphoid layer has IGA, etc.. Deep fibrous layer has collagen fibrils, fibroblasts, blood, vessels, accessory lacrimal glands.
Palpebral marginal conj.
Lines the eyelid margins. Submucosa is thin with only a deep fibrous layer.
Palpebral tarsal conj.
Lines the tarsal plate. Submucosa is thicker. Strongly attached to tarsal plate.
Forniceal conj.
Lines the fornices. The EOM fascia attach to the forniceal conjunctiva that allow conj to move with eyes.
Bulbar conj
Submucosa is losely attached under tenon’s capsule until 3 mm from the cornea where it fuses with tenon’s episclera, and sclera.
What stops at limbus
Bowman’s and descents (continues as Schwalbe’s)
What begins at the limbus
conj stroma, episclera, and tenon’s capsule.
Plica Semilunaris
Made of stratified squamous bulbar conj that folds at the medial cants. Allows eye to move and floor of lacrimal lake.
Caruncle
Conj and skin hybrid with sebaceous glands, sweat glands, and goblet cells. Function is unknown.
What drains the bulbar and palpebral conj
anterior ciliary veins
What supplies blood to palpebral conj?
Palpebral arcades
What supplies blood to bulbar conj?
Posterior supplies to peripheral palpebral arcades and anterior bulbar by anterior ciliary arteries.
Anterior lens radius of curvature
8-14
Posterior lens radius of curvature
5-8
Lens capsule
Transparent basement membrane that surrounds the entire lens and is secreted by the anterior lens epithelium. Zones insert here.
What collagen is lens capsule made of
Type 4
Lens epithelium
Single layer of cuboidal cells adjacent to the lens capsule. Joined to together by macular occludences and gap junctions
Pre-Equatorial region of the lens
Just anterior to the lens equator and known as the germinal zone. Contains mitotic epithelial cells that become secondary lens fibers.
Lens cortex
70% water and 30% protein (highest in body). Most lens proteins are water soluble.
Crystalline in the lens cortex
Have alpha, beta, and gamma. Alpha crystalline are in charge and help the others. When we loose them we get cataracts.
Index of refraction in the cortex
Gradient index highest in the nucleus.
Lens Zonules
BM of NPCE creates lens zonules. Has no true elastic fibers.
Primary lens zonules
Attach directly to the lens zone in the pre and post equatorial regions
Secondary lens zonules
Connect primary lens zonules to one another or the NPCE of the pars plana
Tension zonules
connect the primary lens zonules to the alleys between the ciliary processes of the pars plicate.
Where is the sclera thickest? how thick?
posterior pole at 1 mm
Where is the clear thinnest? how thin?
Under recti tendon insertions. 0.3 mm.
Where is the weakest area of the sclera
lamina cribosa
Is the sclera vascular?
NO. Considered avascular. Receives minimal blood supply from episcleral vessels, choroidal vessels, and branches of LPCAs.
Layers of the sclera
episclera, sclera proper, lamina fusca
Episclera
Loose CT layer that contains a capillary network for Anterior ciliary arteries. Will get injection with CB or iris inflammation.
What is on top of the episclera?
Tenon’s capsule
Sclera Proper
Thick, dense, avascular CT. Irregular collagen bundles that provide strength but no transparency.
What is sclera proper a continuation of?
Corneal stroma
Episclera vs. sclera proper
Episclera is loose CT and highly vascular. Sclera proper is dense CT and is relatively avascular.
Lamina Fusca
The innermost layer of the sclera. Adjacent to choroid and continues elastic fibers and melanocytes.
Tenon’s Capsule
Thin transparent layer that covers the episclera. Pierced by EOMs, vessels, etc.
Layers of the eye from anterior to posterior
conj epi, conj. stroma (submuconsa), Tenon’s capsule, episclera, sclera proper, lamina fasca.
Anterior sclera foramen
Area occupied by the cornea
Posterior sclera formaen
Are occupied by the ON. Lamina cribosa.
Emissaria
Channels in the sclera for things to travel.
Middle emissaria
Vortex veins
Posterior emissaria
LPCAs, SPCA, LPCN, SPCN.
Anterior emissaria
Anything not stated in middle or posterior :)
Internal sclera Sulcus
Located in the eye and has the cornea sclera junction
Becker-Shafter Grade 4
Most posterior structure seen is CB
Becker-Shafter Grade 3
Most posterior structure seen is sclera
Becker-Shafter Grade 2
Most posterior structure seen is 1/2 to 1/3 TM
Becker-Shafter Grade 1
Most posterior structure seen is anterior aspect of TM or schwalbe’s line
Becker shaffer grade 0
no structures seen
Van Herick grade 4
Anterior chamber is >1/2
Van Herick Grade 3
Anterior chamber is 1/2 to 1/4
Van Herick Grade 2
Anterior chamber is =1/4
Van Herick Grade 1
<1/4
Van Herick Grade 0
no structures visible
What attaches to the Scleral Spur
TM and longitudinal muscle fibers of the CB
Which layers of the sclera contain elastin
Lamina fuscha, lamina cribosa, and SS
Which part of the angle typically contains the most pigment
inferior
Uveoscleral meshwork
Innermost 1-5 layers of the TM. Large pores. Does not utilize Schlem’s canal. Aqueous flows between the ciliary muscle fiber bundle, into the suprachoridal space, and then through the sclera or through the anterior ciliary veins, vortex veins, or other routes.
What to prostaglandins due
Decrease resistance in uveoscleral meshwork.
Corneoslceral Meshwork
Outer 8-15 layers. Has smaller pores. IOP must be greater than venous pressure.
Juxtacanalicular Tissue
AKA cribifirm layer. Located closest to schlem’s canal. Much resistance.
Schelmm’s Canal
A major site of aqueous humor filtration. Inner wall has vacuoles to collect for JXT. Has internal collector chambers to increase the SA.
Routes of schelemm’s canal drainage
Short efferents->deep scleral venous plexus–>intrascleral venous plexus–>Episcleral venous plexus OR external collector channels (aqueous veins of Ascher)–>episcleral venous plexus.
Pupil location
Slighting IN.
Schwalbe’s contraction furrows
At the pupillary margins. Represent variation in thickness of the Posterior pupillary iris.
Where is iris thickest?
collarette
Where is iris thinnest
Iris root
Collarette
Attachment for fetal pupillary membrane and has old fetal vasculature. Divides iris into pupillary and ciliary zones
Ciliary zone
Contains iris furrows that allows iris to bunch with dilation. Also has radial streaks which are white in color and represent collagen traveling with iris vessels.
Pupillary zone
Radial streaks are still present but are smaller.
Crypts of Fuchs
Span the collate into ciliary and pupillary zones
Anterior iris stromal leaf
Located in ciliary zone. Contains the ABL and a small portion of the iris stroma.
Posterior iris stromal leaf
Contains most of the iris stroma in the ciliary ABL and all of the iris stroma in the pupillary zone.
What determines iris color
amount of melanin not amount of melanocytes.
Iris crypts
columns in ABL that serve as passageway for aqueous humor.
Cells of the iris stroma
fibroblasts, melanocytes, lymphoctyes, macrophages, mast cells, clump cells.
What is the iris stroma continuous with?
Ciliary body stroma
Nerves of the iris stroma
LPCNs and SPCNs.
What carries sensory and sympathetic signals to iris stroma?
LPCNs and SPCNs
What carries parasympathetic signals to iris stroma
SPCNs.
What is the blood aqueous barrier
minor ACI, endo of scheme’s canal, NPCE.
MACI
Major. Formed by LPCA and ACA. In the CB and extends to the iris root.
Minor ACI
Located in the iris stroma near pupillary margin and inferior to collarette. Formed by branches of MACI.
Radial veins
Veins of the iris and parallel the arteries. Drain into CB veins–>choroidal veins–>vortex–>super/inferior SOV.
Sphincter muscle
Present in the iris stroma.
What innervates the sphincter muscle
SPCN that travel with CN III
Anterior epithelium
Lies closest to iris stroma and becomes the pigmented ciliary epithelium. Contains pigment myoepithelial cells which which contain processes at basal surface that extend into iris stroma and attach to sphincter. This forms the dilator muscle
Dilator muscle
in the anterior epithelium layer. Extends from the iris root and stops at midpoint of sphincter.
Posterior Pigments Epithelium of Iris
Heavy pigmented single layer of columnar cells.
Pupillary ruff
PPE of iris extends around pupil.
What kind of transillumination defects will see with pigment dispersion syndrome
mid peripheral.
Iris cysts
Develop when there is separation between pigmented anterior layer and pigment posterior epithelium layer.
Where is the posterior chamber located
Between the iris and anterior vitreous.
Posterior chamber proper
bound by posterior iris epithelium, Cilliary processes, and the anterior zonules and surface of lens.
Canal of Hannover (aka circumlental space)
Between the anterior and posterior lens zonules. Hannover=pushover=always in the middle.
Canal of petit (aka retrolental space)
located between the most posterior lens zonules, anterior hyaloid membrane, and posterior portion of the CB.
Function of the CB
Aqueous humor production, Accommodation CN III.
How is the CB innervated by parasympathetic
CN III carry SPCN
Pars Plicata
Corona Ciliaris. Wide anterior portion that contains 70-80 Ciliary processes. The NPCE of the pars plicate is responsible for the production and secretion of aqueous humor into the posterior chamber
Par Plana
Orbiularis ciliaris. Flatter, more posterior.
Dentate processes
The teeth.
Oral bays
Part of CB. The ovals.
Enclosed oral bay
neighboring dentate processes joining together
Valley of Kuhnt
Heavily pigmented areas located between ciliary processes.
Where do the lens zonules come from
Mostly the NPCE of the pars plans.
Course of he lens zonule
Produced by the pars plans and then course forward to the valleys of kunt before inserting in the lens capsule.
Supraciliaris
The outermost layer of the ciliary body. Loosely attached to underlying sclera. It is a potential space. It is continuous with the suprachoriod at the ora errata. Blood vessels and nerves travel here.
Where does a ciliary body detachment occur
Fluid in Supraciliaris
Ciliary Muscle Longitudinal fibers
Outermost fibers that are most of the CM fibers. Originate at the SS and TM with legs extending into the chord as stellate shaped terminations (muscle stars)
Radial fibers
Also extend from SS.
Muller’s annular Muscle
Smallest CM fibers. Most medical and located near MACI. originates from SS and has same effect as sphincter
Ciliary Stroma
Contains MACI.
Pigmented Ciliary Epithelium
The outer cuboidal epithelial layer layer that is attached to the ciliary stroma.
NPCE
Responsible for controlling aqueous
What supplies the CB with blood
MACI
What drains CB
Vortex veins
Innervation of the CB
- CN III carry parasympathetic fibers from SPCNs. 2. SNS travels with SPCNs and LPCNs for arteries 3. Sensory nerves from V1 travel with LPCNs.
Where is the choroid thickest
posterior pole 0.2 mm
Where is choroid thinnest
Ora serrata 0.1 mm
Suprachoroid
potential space between the sclera and choroid vessels. Passage of LPCN and SPCN occurs here
Where do you see LPCN in BIO
3 and 9
Who does the suprachorid layer belong to (lamina fuscha)
Both choroid and sclera. If there is a seperation part will stick to choroid and part to sclera.
Choroidal stroma
Have choroidal blood vessels, nerves, and melanin. Innervated by the sympathetic NS which causes construction. The high density of bv and melanocytes gives the chance for nevus to occur.
Haller’s Layer
Posterior layer of choir formed by SPCAs. Composed of large vessels that branch into smaller vessels in settler’s layer.
Sattler’s layer
More anterior and smaller vessels that branch to form a capillary bed.
Choriocapillaries
Composed of large fenestrated capillaries that are most concentrated in the macula. Nourishes the outer layers of the retina.
Pericytes
surround blood vessels and regulate flow.
Bruch’s Membrane
Thin innermost layer of choroid. Represents the fusion of the RPE and Choriocapillaris.
Layers of bruch membrane
BM of choriocapillairis, Outer collagen layer, elastic layer, innercollegent layer, Bm of RPE.
Functions of bruch membrane
allow passage of nutrients from choroid to Retina, Waste products pass to choroid, phosolipids accumulate with age and cause drusen and stop transport.
What conditions have angoid streaks
PEPSI. Psuedoxanthoma elasticum, Ehlers-dahlos, Pagets, Sickle cells, Idiopathic
What conditions cause neovacsularization
CH BALA. Choroid rupture, hitso, Bests, Angoid, Lacquer, ARMD.
Innervation of the choroid
Sympathetic fibers cause vasoconstriction, CN VII parasympathetic from ptergyopalantine cause vasodilation, CN III parasympathetic have unknown function, CN V1 provides sensory information.
Patellar fossa
Anterior depression of the vitreous due to the lens
What type of collagen is the vitreous
Type II
Where do most of the changes in vitreous with age occur?
Central vitreous
Halocytes
The predominate cell type in the vitreous and are only found there. Synthesize HA and have phagocytic properties.
Hyaluronic acid
The gag in the vitreous.
Fibroblasts in the viterous
Predominately in the base and synthesize collagen.
Virtual attachment from strongest–>weakest
Vitreous base, posterior lens, optic disc, macula, BV.
Vitreous cortex
Outer region of the vitreous adjacent to the retina that extends to ora errata. High density of collagen fibrils, cells, proteins, a mucopolysaccharide filler substance.
Anterior Hyaloid
Extends from the vitreous base to attach to the lens.
Hyaloideocapsule ligament of Weiger
Strong circular adhesion between the anterior vitreous, posture zonules, and the posterior capsule of the lens.
Berger’s space
Potential space between anterior hyaloid and the posterior lens capsule that is located in the central non-attachment area of Weiger.
Posterior hyaloid
From vitreous base to ON.
Cloquet’s canal
AKA hyaloid channel or retrolental tract. A normal remnant of primary vitreous in the middle of the vitreous. Low density liquid fluid surrounded by high density. The former sight of the hyaloid artery.
What happens to the hyaloid artery
After birth it regresses to the optic disc where it becomes the CRA.
Area of Martegiani
The posterior end of cloquet’s canal that is in contact with the OD.
Epicapsular star
On anterior lens capsule. It is the embryological remnant of the former connection between the tunica vasculosa lentil and the posterior hyaloid artery.
Mittendorf’s dot
Embryological remnant of the hyaloid artery on the posterior lens capsule
Bergmeister’s papillae
Embryological remnant of the hyaloid artery on the optic disc.
Function of RPE
Phagocytosis of Phot outer segments, Transfer of ions, water, and metabolites, Vitamin A storage, Blood retinal barrier, Absorbs light, produces growth factor.
Inner segment of photoreceptors
Produce photopigments that are transported to outer segment.
Myoid
The inner layer of inner segment. Makes protein.
Ellipsoid
The outer layer of inner segment. Packed with mito for energy.
Cilium
Connects the outer and inner segment.
Outer Segment
Stacks of membrane discs that contain photopigments.
OS of rods vs. cones
Disc membranes are continuous with disc in cones but are not in rods. (free floating)
Where is the rod density greatest
5 mm (20 degrees) from the fovea in an area known as the rod ring.
What wavelength does rhodopsin absorb maximally
507 nm
What do rods terminate in
Sphericals
Cyanolabe (blue)
440
Chlorolabe (green)
535
Erythrolabe (red)
565
Where is the fovea
5 mm temporal and 0.4 mm inferior.
ELM
Not a true membrane. Formed by mueller cels and inner segments of the photoreceptors
ONL
Contains the cell bodies of rods and cones
OPL
Synapses between Photo, horizontal, Bipolar.
Rod Spherule
Can synapse with 1-4 rod bipolar cell dendrites and horizontal
Con pedicule
Can form a synaptic triad (3 horizontal or 2 horizontal and one bipolar).
Who can cone pedicure synapse with
Midget, flat, or diffuse flat bipolar cells.
Henley’s layer
The OPL in the macula
Where does OPL get is blood
booth choroid and retina.
Who does CRA supply
NFL, GCL, IPL, INL, OPL
Where does retinoschisis occur
OPL
Where are hard exudates located
OPL
INL
Cell bodies of bipolar, horizontal, interplexiform, amacrine, mueller cells.
Midget bipolar cells
Connect to only one cone and one ganglion. Resolve fine detail. Found in the fovea.
Flat bipolar cells
Connect with several photoreceptors
Diffuse flat bipolar cells
Connect with numerous cone receptors (more than flat)
Horizontal cells
Carry information laterally within the retina through synapse of photoreceptors, bipolar and other horizontal cells. Give inhibition.
Interplexiform cells
Rely information between the IPL and OPL
Amacrine cells
Connect bipolar, interplexiform, ganglion, and amacrine.
Mueller cells
Found from ILM to ELM. Provide structural and nutritional support.
Which cells in the retina are inhibitory
Horizontal and amacrine
Layers the receive blood from the CRA
NFL and INL
Inner Plexiform Layer
Amacrine cells synapse with self, bipolar, and ganglion.
Bipolar vs. amacrine cells
opposite effects
Ganglion Cell layer
Each ganglion cells has a single axon that travels and terminates in the lgn.
P-cells
Type of ganglion cells. Deal with color and fine detail.
Where in LGN do parvo axons go
3,4,5,6
P1 cells
Midget ganglion cells. Most common. Have only one dendrite that synapses with one midget bipolar cell that synapse with one cone in fovea.
P2 cells
Larger than P1 with multiple dendrites. Less common.
M-Cells
Type of ganglion cell. Sensitive to dim changes in illumination and motion.
What layer in LGN cells project
1,2,
NFL
Composed of the axons that collectively form the ON
Where is the ON thickest?
ISNT.
Papillomacular bundle
NFL fibers that extend from the temporal macula and to the ON.
CWS
(soft exudates) Located in the NFL
Splinter hemorrahges
(dance hemes) are in NFL. Occur with normotensive glaucoma
Flame hemorrhages
Within the NFL. Associated with retinal vascular pathology.
Dot blot hemes
Within the NFL
ILM
Formed by Muller cells.
ILM over disc
Astrocytes take over for muller.
Epiretinal membranes
Occur in the ILM and are commonly located in the macula.
Mueller Cells
Located in ILM to ELM. Provide structural and nutritional support. Aid in glycogen metabolism (store so photoreceptors always have nutrients), act as a buffer, and absorb and recycle metabolic waste products.
Fiber baskets
Although mueller not found within photo layer microvilli of the cells may extend and form a fiber basket
Astrocytes
Help form the ILM at the optic disc. Similar functions as mueller cells
Microglial cells
phagocytic cells that respond to inflammation or injury. Found everywhere.
Role of neuroglia cells in Retinal processing
NONE
Capillary networks in the retina
NFL and INL.
cilioretinal artery
Branch from the SPCAs of the choriocapillaris that supplies the inner layer of the retina. Present in 15-20% of population.
AV crossings
A and V share a common adventitia at crossings. Damage to the arterial wall results in venous wall compression and thrombus formation.
Macula diameter
5.5 mm or 18 degrees
Fovea
1.5 mm diameter (1DD).
How much of fovea is avascular
0.4-0.5 mm.
Foveala
0.35 mm in diameter and 0.13 mm in thickness. Has only photoreceptors.
What photoreceptors are not in the foveala
No blue cones or rods
Parafovea
0.5 mm zone that surround the fovea. Has all retinal layers. Thickest area of the retina.
Clivus
In parafovea. Sloping of the retinal layers.
Perifovea
1.5 mm zone. Occurs when ganglion cell layer becomes 4 cells thick. Boundary between perifovea and periphery occurs when ganglion cell is 1 cell thick.
CN V
Trigeminal. Sensation and mastication.
CN 8
Sensory. Hearing and balance.
CN 9
Glossopharyngeal. Both. Post 1/3 taste, swallowing, salivation, monitors carotid sinus.
CN 7
both. Facial expressions, lacrimation, salivation, ant 2/3 taste.
CN 10
Vagus. Both. Taste, swallowing, palate elevation, talking, thoracoabdominal viscera.
CN 11
Accessory. Motor. Head turn, shoulder shrug
CN 12
Hypoglossal. Motor. Tongue movement.
Where will the tongue devaiate
Towards the lesion
Where will the uvula deviate?
Away
What visual field does the optic tract carry
Information from the same side of the visual field.
What destinations does CN II Have
- LGN 2. pretectcal nucleus (pupils) 3. Supeior colliculus (saccades)
MLF
Connect CN III nucleus to CN IV, VI, and CN VIII.
Which nucleus in CN III are ipsilateral?
MR, IR, IO
Which nucleus in CN III are contralateral?
SR
How many nucleus are there for the elevator?
ONE
Where doe CN III travel close to
Posterior communicating artery
Superior devision of CN III
SR, levator. Sympathetic fibers for mueller also comes.
Inferior division of CN III
Innervates the MR, IR, IO, iris sphincter, and ciliary muscle. Has parasympathetic fibers from the EW
Lesion of CN III
Eye down and out.
A CN III that contains the pupil
Suspicious of aneurysm.
What likely causes a pupil sparing CN III lesion
ischemia of the small blood vessels that nourish the inner fibers of CN III.
Which is the longest and skinniest CN
CN IV.
Where is CN IV located
At the midbrain by the inferior colliculus.
What is unique about CN IV’s Path
ONLY cranial nerve to leave the dorsal side of the brain steam and cross to innervate the contraleral oblique.
SOURS
SO tilt to unaffected side. SR to same side.
Does CN IV go through the annulus of Zinn?
NO. It is superior.
Which are the only two muscles that receive innervation from the contralateral nucleus
SO and SR.
Division of the VI
Nasociliary, Frontal, Lacrimal
Nasociliary division of V1
Includes Infratrochlear, LPCA, SPCA, and ethmoid.
Frontal Nerve
Includes the supraorbital and supratrochlear.
Lacrimal Nerve of V1
Provides sensory feedback to the lacrimal gland.
Parasympathetic innervation to the lacrimal gland
The zygomatic (V2) carries parasympathetic fibers from CN VII from the ptergyopalantine ganglion to the lacrimal nerve of V1.
V2 Maxillary Division
Includes the infraorbital and the zygomatic nerve.
How does V2 enters the skulls
Foramen rotundum.
V3
Mandibular devision. Provides sensory innervation to lower face and motor innervation for mastication.
How does the abducens nerve travel?
Makes a tight bend over the petrous ridge of the temporal bone.
What can cause CN VI palsy
increased ICP or Internal carotid artery anurysm
Who travels closest to the internal carotid artery
CN VI
Course of CN VII
Starts in frontal lobe, travels to the pons, go through the internal auditory canal and through the geniculate ganglion and then branches into the greater petrosal nerve and the chords tympanic nerve and the others go to the face.
Greater petrosal nerve
Caries parasympathetic innervation to the lacrimal grand. Greater petrosal joins deep petrosal to form the vidian nerve that then goes to pterygopalantine ganglion and then join zygomatic branch that then communicates with V1.
Chords tympani n.
Carries taste fibers from the anterior 2/3 of the tongue and para to submandibular and sublingual glands.
Facial expression nerves
Main root of CN VII enters the parotid gland and divides into five branches to supply the muscles of the facial expression
Temporal branch of facial expression
Supplies procures, corrugated, occipital frontal, and orbicularlis oculi
Zygomatic branch of facial expression
Orbicularis occult.
Does CN VII innervate the parotid gland?
No the glossopharyngeal does. It just divides in there
What happens in the parotid gland
CN VII splits and the superficial temporal vein joins with the maxillary vein to form posterior facial vein.
Stroke
supra nuclear. Contralateral impaired innervation to he contralateral muscles of the lower face.
Bell’s palsy
Lower motor neuron. Ipsilateral. Impaired innervation of upper and lower.
Where does parasympathetic innervation come from?
CN III and CN VII
Sympathetic innervation to the eyes?
Travels with ICA. Can branch to CN III for mueller, CN V1 to travel with LPCNs or SPCNs to iris dilator or choroidal and conj blood vessels, or blood vessels of the lacrimal n. by the vidian nerve.
1st order sympathetic fibers
Begin in hypothalamus and decent in C8-T2 to synapse in ciliospinal center of Budge
2nd order sympathetic fibers
leave the ganglion and travel around the clavicle an across the apex of the lungs before entering the superior chain ganglion
Post ganglionic fibers
Come from the superior chain ganglion and travel with ICA through carotid canal.
Where is the CSF?
subarachnoid.
Intraorbital potion of ON
surrounded by pia, arachnoid, and dura.
What surround the intracranial portion of the ON?
Only the pia mater.
Why do we get papilledema?
CSF fluid spreads into the ON.
What provides myelination after the lamina cribosa?
oligodendrocytes
Why is there pain on eye movement with lamina cribosa?
The SR and MR shares an optic sheath with the ON.
Can the optic nerve auto regulate?
Yes!
Where is the ON located
15 degrees from fixation
Is the On larger vertically or horizontally
vertically
What is the ILM for the ON
Astrocytes (not mueller)
How long is the ON
50-60 mm
Pre-laminar ON
Anterior to lamina cribosa. No myelin.
Intermediary tissue of Kuhnt
Separates ON tissue from rest of retina.
Border tissue of Jacoby
Separates the ON from the choid
Border tissue of elsching
Sclera collagen fibers surround glial tissue around the ON.
Intraorbital portion
30 mm. From lamina cribosa to exiting the skull. S-shaped. Myelinated.
Intracanalicular
6-10 mm. Through the optic canal in the cranium.
Intracranial
10-16 mm. Portion of the optic nerve extending from the optic canal to the optic chasm.
Anterior knees of wilbrand
Inferior nasal fibers that loop anterior into the contralateral track. AIC.
Posterior knees of wilbrand
Superior nasal fibers that loop posteriorly into the ipsilateral optic tract before crossing through the optic chasm. PIS.
Optic Track
Superior are medial side, Inferior are lateral. Macular are middle.
LGN layers
At the thalamus. Mango layers 1,2. Parvocellular 3-6. Koniocellular are between.
Uncrossed fibers of the optic synapse in
2,3,5
Crossed fibers of the optic synapse in
1,4,6
The orientation of different fibers
Superior are medial. Inferior are lateral.
Optic radiation inferior
Inferior radiations-fibers travel through the temporal lobe and around the lateral ventricle into the parietal lobe and form meter’s loop
Optic radiation superior
Superior radiation-Course directly through inferior parental lobe and terminate in occipital lobe.
Optic radiation mnemonic
SPIT(M).
Calcimine fissue
Divides occipital lobe into anterior and posterior
Cuneus gyrus
Superior fibers terminate here
Lingual gyrus
Inferior terminate here
SCIL
Superior cuneus, inferior lingual.
Macula in V1
Project to the outer surface of the apex of the occipital lobe. Superior to cuneus and inferior to lingual.
Summary of inferior retinal fibers
lower fibers course laterally in optic tract to form milers loop and end in lingual gyrus.
Layer 4 of V1
Synapses between optic radiations and neurons in cortex. Sent to higher cortical area for processing
Layer 5 of V1
Send to superior colliculus
Layer 6 of V1
Provide feedback to lgn.
Ocular dominance columns
in V1. fibers from only one eye
Blood supply to optic chiasm
Circle of willis and branches of ICA
Blood supply to the optic tracts
Anterior choroidal branch of the middle cerebral artery
LGN blood supply
Suppled by anterior choroidal and posterior cerebral arteries
Optic radiation blood suply
Suppled by anterior choroidal, middle cerebral, and posterior cerebral
V1 blood supply
posterior cerebral artery and middle cerebral artery
Post chasmal lesion
Homonymous visual field defects on the same side.
Most posterior a post chasmal lesion is located the more ______ the defect is
congruous
Temporal lobe defects
Defect for inferior eye–>superior VF defect. Pie in the sky.
Parental lobe defects
Defects of superior eye–>pie on the floor.
Which VF results in asymmetrical OKN response?
Parietal
Is visual acuity affected in post chasmal lesions
No. Unless bilateral lesions are present. Only if both blood supplies to V1 are obstructed and that is rare.
Macular sparing homonymous hemianopsia
most commonly a stroke that affected middle or posterior cerebral but not both.
Macula only homonymous hemianopsia
Most likely a tumor that has compresses both blood supplies to the macula cortex.
Bitemperoal hemianopis
Pituitary gland tumor
Junctional scotoma
Optic chiasm lesion that gets central vision loss in one eye and anterior knee of wilbrand.
Vf defects that respect the horizontal midline
Lesions anterior to the chiasm
What are most homonymous hemianopsia due to ?
Strokes. (except macula only homonomoys hemianopsia)
ON lesions
Asymmetrical. Typically respect the horizontal median.
Retinal lesions
Asymmetrical. Will not respect any midline.
