10-20 Orbit I Flashcards
A: Describe the 3 RIM BONES of the Orbit
B: Now describe the 4 bones INSIDE the Orbit
A:
1. Frontal = Superior / ROOF
2. Zygomatic = lateral
3. Maxilla = Medial, Inferior / FLOOR
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B: “PELS” inside the orbit
ºPalatine= part of medial floor posteriorly
ºEthmoid= extremely thin (lamina papyracea) / medial
ºLacrimal= creates fossa for lacrimal sac / medial
ºSphenoid= Special bone tht optic canal runs thru medially
Describe Sphenoid bone positioning INSIDE the Orbit [5]
- posterior & lateral
- greater & lesser wings form SUP orbital fissure
- inferior orbital fissure is between Grtr wing & Maxilla
- fissures meet medially
- Optic canal runs thru Sphenoid body medially
Describe the 6 BOUNDARIES of the ___shaped Orbit
- Base
- Apex
- Superior wall
- Medial Wall
- Inferior wall
- Lateral wall
Orbit = PYRAMID SHAPED ºBase= Orbit Rim
ºApex= points posteromedially to optic canal and has center axis which points to sella turcica @ 22.5º
ºSuperior Wall= frontal bone (small portion of sphenoid lesser wing)
ºMedial Wall = parallel to opposing orbit–>composed of ethmoid and lacrimal [frontal,maxilla,sphenoid]
ºInferior Wall=Maxilla & small part of zygomatic,palatine
ºLateral wall= THICKEST orbit wall set at 90º to opposing orbit’s lateral wall–> Zygomatic & Sphenoid
A: List AND DESCRIBE the 7 layers of the Palpebrae (AKA ______) from superficial to DEEP
B: What is its function
A: Palpebrae = “ Eyelids “
- Skin
- Subcutaneous loose connective tissue=moves skin
- Muscular layer=palpebral part of Orbicularis oculi m.
- Submuscular loose connective tissue=contain Facial CN7 —> innervates Orbicularis oculi m.
- Tarsal Plate
- Tarsal GLANDS
- Palpebral conjunctiva
B: protects & aids in eye lubrication
Describe the Skin Layer of the Palpebrae (AKA _______) [3]
Palpebrae SKIN
- Contains Moll sweat glands & Zinn sebaceous glands
- has specialized hairs [eyelashes] growing from ANT mucocutaneous border
- contain [ciliary stye glands]= eyelash sebaceous glands
Describe the TARSAL Plate Layer of the Palpebrae (AKA _______) [3]
Palpebrae = “Eyelids”
ºgives eyelid stiffness
º associates with [levator palpebrae superioris m.] superiorly= raises eyelid
º levator superioris m. also contains tarsal Muller’s m.= INC tone
Describe the TARSAL GLAND Layer of the Palpebrae (AKA _______) [3]
Palpebrae = “Eyelids”
- long glands underneath TARSAL plate
- lubricates mucocutaneous junction preventing sticking
- forms tight seal when eyelids closed
Describe the Palpebral conjunctiva Layer of the Palpebrae (AKA _______) [4]
Palpebrae = “Eyelids”
- DEEPEST layer of eyelids
- mucous membrane on inner eyelid that moistens eyelid
- continuous w/bulbar conjunctiva @ superior/inferior fornix
- superior fornix receives lacrimal gland secretions
A: What 4 things can you see from the ANTERIOR view of the eye?
B: Describe each ANT eye component
A: Palpebral fissure =space between upper & lower palpebrae
C: Lacrimal CARruncle= fleshy elevation inside Lacrimal lake that houses sweat/sebasceous glands, cilia & produces yellowish sandman secretions during sleep
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D: Plica semilunaris= connective tissue band lateral to CARuncle that’s homologous with nictitating membrane “3rd eyelid”
1- What does the [Lacrimal Apparatus] do?
2-Name the 5 structures it’s composed of
1- Provides lubrication to ANT eye surface
2- A: Lacrimal Glands B: Puncta lacrimali C: Lacrimal canaliculus D: Lacrimal sac E: Nasolacrimal duct
A: Describe the 3 major features of the Lacrimal Gland
B: Where is this gland found?
C: Where do tears secreted collect?
A: 1. has small palpebral part on inner surface of eyelid
—>can see with reflected eyelid
2: has LARGE Orbital part containing interlobular ducts tht form multiple excretory ducts
B: Found In [Lacrimal Apparatus]
C: Secreted tears collect in upper lid SUP fornix & pass over eye surface with blinking
1) How do Secreted Tears reach the eye surface
2) Tears are secreted by which Gland and by which Cranial Nerve?
1) Secreted Tears collect in upper lid’s SUP fornix and pass over the eye surface with the aid of blinking
2) Tears = Lacrimal Gland = [Facial CN7^greater petrosal n.] [GVE component]
Briefly describe these structures of the [Lacrimal Apparatus] and where they’re located….
1: Puncta Lacrimali
2: Lacrimal Canaliculus
3: Lacrimal sac
4: Nasolacrimal duct
1: PL=openings in medial aspect of upper/lower eyelids that tears drain into. Found on top of [lacrimal papillae] elevations
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2: Lc=canal duct tht connects [Puncta lacrimali] with [lacrimal sac]. Found on upper/lower Palpebrae
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3: LS= oblong “sac” that rest inside lacrimal bone fossa. Connects to [Puncta lacrimal] via
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4: NLD= Drains fluid into nasal cavities. Found inferior to [Lacrimal sac] and ANTERIOR to [inferior nasal meatus]
Describe the SYMPATHETIC pathway to the Lacrimal Gland [4]
1st: preganglionic fibers originate from upper thoracic cord
–> travel in sympathetic chain to SYNAPSE in Superior Cervical ganglion
——> the now POSTganglionic fibers follow carotid plexus to form [DEEP PETROSAL n.] which joins w/[greater petrosal n.] = n. of pterygoid canal/vidian n.
LAST: sympathetic fibers ONLY PASS thru [pterygopalatine ganglion] & follow same course as PARAsympathetic fibers to lacrimal gland
1) [Parasympathetic GVE] preganglionic secretomotor fibers traveling to [Lacrimal Gland] originate from which nucleus?
2) What main nerve does these fibers travel as?
1) Superior Salivatory Nucleus
2) [greater petrosal n. ] daughter of Facial CN7
A: Name the 7 Orbit Muscles and describe their function
B: MOST of these muscles are innervated by the _____ CN except 2. What are they and name their innervation
C: Which of these muscles originate from the [common annulus tendinous ring]
- Levator Palpebrae superioris=raises eyeLID
- Superior rectus=elevates & ADDucts
- Medial rectus= ADDucts eye
- Inferior rectus= depresses&ADDucts
- Inferior Oblique = elevates&ABducts
- Lateral rectus= ABducts eye
- ## Superior Oblique= depresses&ABductsB: 1-5= [Occulomotor CN3]
C: All 4 RECTUS MUSCLES
[Superior Oblique Orbit Muscle]
- Origin
- Passage
- Nerve innervation
- Function
[Superior Oblique Orbit Muscle]
- originates from sphenoid body above optic canal & medial to SUP rectus m.
- passes thru [Trochlea] anteromedially, inserts onto SUP eye behind eyes midplane and is deep to SUP rectus
- [Trochlear/ CN4]
- depresses&ABducts “Down and Out”
What is the Order of the Orbit muscles from an Anterolateral view
TOP: ºSUP oblique
ºLevator palpebrae superioris
ºSUP rectus
ºmedial rectus
ºINF rectus
ºINF oblique
BOTTOM: ºLateral rectus
[Trigeminal/CN5-B1^Opthalmic] has 3 daughters of its own = NFL
Describe the {Lacrimal n.} daughter [2]
- supplies lacrimal gland, lateral eye & lateral upper/lower palpebrae
- Receives fibers from [B2>zygomatic ] (which joins up with it)..then Carries POSTgnglionic PARAsympathetic AND Sympathetic fibers to distal end lacrimal gland
[Trigeminal/CN5-B1^Opthalmic] has 3 daughters of its own = NFL
Describe the {Frontal n.} daughter and its 2 daughters
[Frontal n.]
A: Travels on top Orbits roof and divides into Supraorbital & SupraTROchlear granddaughter nerves
1. Supraorbital=continues thru & supplies upper eyelid and scalp skin over eye 2. SupraTROchlear= continues medially & innervates [medial canthus] and part of eye scalp near nose's bridge
[Trigeminal/CN5-B1^Opthalmic] has 3 daughters of its own = NFL
A: Describe the 5 {Nasociliary n.} daughter nerve branches
B: How does the {Nasociliary n.} enter the orbit
{Nasociliary} daughter nerve BRANCHES
- [Ciliary ganglion Communicating branch]=sensory fibers to cornea that exit ganglia without synpasing via short ciliary n.
- Long ciliary nerves= innervate cornea & sclera by running directly to back of eyeball
- Posterior ethmoidal=supplies POST & mid ethmoid air cells
- ANTerior ethmoidal= supplies ANT & mid ethmoid air cells
- Infratrochlear =
ºTERMINAL nasociliary branch found beneath trochlea, that innervates [medial canthus] & lower eyelid
ºalso creates [external nasal n.] which supplies bridge & SUP part of nose
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B: [Nasociliary n.] enters orbit LATERALLY, then crosses above optic nerve to create it daughter nerve branches
[Trigeminal/CN5-B2^Maxillary]
1. What does this n. innervate? [3]
- Describe its passage route [2]
[Trigeminal/CN5-B2^Maxillary]
1. innervates SENSORY to orbit floor, orbit lateral & ANT face below orbit to the level of upper lip
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2.
ºruns in floor via infraorbital groove–>births [zygomatic branch] daughter then continues to enter infraorbital canal
ºFinally terminates anteriorly by exiting infraorbital foramen as [infraorbital n. branch]
1) How does the Preganglionic PARsympathetic fibers reach the ciliary ganglion
2) Where is the ciliary ganglion found?
A: What does Ciliary muscle do?
B: What does the Sphincter pupillae m. do?
1) Pregang fibers originate in [Edinger-Westphal nucleus] and travel in inferior division of [Oculomotor CN3] (specifically inf oblique m. branch) –>to reach ciliary ganglion
2) CG found lateral & inferior to the optic nerve, just proximal to where it enters eye
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3) POSTgang enter eye via [SHORT ciliary n.] which run a circle around eye in uveal layer
- —>ciliary m. and sphincter pupillae m.
A: ciliary m.= changes shape of lens causing it to thicken (INC curvature) & focus on near objects
B: Sphincter pupillae m.= constricts pupil
1) How does the Preganglionic Sympathetic fibers reach the superior cervical ganglion
2) Describe passage of POSTganglionic Sympathetic fibers
3) There are 2 ways these fibers enter the eye. What are they?
4) What does the Sympathetic fibers do in the eye
1) Pregang fibers originate in [IML lateral horns] of upper thoracic spinal cord–>exit ventral root–>ascend to SUP cervical ganglion of the neck
2) POSTgang fibers follow carotid artery into skull, eventually traveling in cavernous sinus to join [CN5-B1].
- –>BOTH then enter orbit via Superior orbital fissure
3) A: travel thru ciliary gang (NO SYNAPSING) and into eye via short ciliary n.
B: DIRECTLY into eye via long ciliary n.
4) INNERVATES [Dilator pupillae m.]=Dilates pupil
[ Opthalmic Artery ]
1) What does it supply?
2) What is its Parent artery?
3) How does it enter the eye?
- supplies ALL orbit structures including lacrimal gland, eyeball and muscles
- Direct branch off [Internal Carotid a.]
- Enters eye via optic canal ( with but lateral to optic n.)
A: Opthalmic artery enters the eye ______ to the optic nerve and follows a course similar to what nerve?
B: Name the 7 branches this artery gives way once it enters and what they perfuse
A: Opthalmic artery enters eye LATERAL to optic n. and follows course similar to [nasociliary n. ]
B:
- [Short & Long POST ciliary a.]= perfuses eyeball
- Lacrimal a. = lacrimal gland & lateral palpebrae
- Muscular branches = extraocular m.
- POST ethmoidal a. =POST & mid air cells
- Supraorbital a. = follows supraorbital n. to supraorbital foramen–> exits orbit to perfuse forehead & scalp
- ANT ethmoidal a. = ANT & mid ethmoid air cells
- Supratrochlear a. = follows Supratrochlear n. to medial canthus = medial forehead
- Dorsal nasal a. = lacrimal sac & lateral nose
1) The Lacrimal artery runs ____ to supply the ___gland and _____ _____.
2) Name the other 2 daughter branches this artery creates?
3) What is the Lacrimal artery PARENT ARTERY?
1) Lacrimal a. runs LATERALLY to supply lacrimal gland and lateral palpebrae
2) A: recurrent eyeball branch-ANT ciliary a.
B: branches to lateral wall of orbit
3) OPTHALMIC ARTERY[from Internal carotid a.]
A: Orbit Venous drainage occurs through which veins? [2]
B: These veins exit thru the ____ ___ ___ and drain into the _____ ____
C: Which vein also drains inferiorly to the [pterygoid plexus]
D: Veins from the eye are called ______ _____
A: Orbit venous drainage=SUP and inf Opthalmic veins
B: These exit thru Superior Oribtial fissure and then drain into the [CAVERNOUS SINUS]
C: inf Opthalmic vein also drains inferiorly into [pterygoid plexus]
D: Eye veins = VORTICOSE VEINS
1) Retina venous drainage occurs via the _______, which normally drains DIRECTLY to the ____ ____
2) Opthalmic Veins also receive blood from Facial Veins. Which Facial veins? [4] Why is this a possible problem?
1) Retina venous drainage occurs via [central vein of retina], which normally drains DIRECTLY into [CAVERNOUS SINUS]
2) Facial VEINS: Supraorbital/ Supratrochlear / Angular / Facial all 4 drain into Opthalmic Veins —–>possibly bad becuz may serve as route for infection
CHALAZION
Inflammation & Red Lump formation 2º to blocked [meibomian gland]
