Anatomy of the eye & orbit (Moff-sizzle)

If you're looking at a mountain range, what is occurring in your eye? -Ciliary muscle -Suspensory ligament -Ciliary processes

-Ciliary muscle relaxes, tension on suspensory ligaments of the lens -Ciliary processes pull on the lens and cause it to be stretched and thinned

The ophthalmic nerve, gives off a nasociliary, frontal, and lacrimal branches. The nasociliary nerve off the ophthalmic nerve, provides GSA to which 5 regions around the eye?

-Conjunctiva -Ethmoid sinuses -Nasal mucosa -Skin of nose -Skin of medial upper eyelid

What are the actions of superior oblique? (3)

-Depression -Abduction -Intorsion

What are the actions of inferior rectus? (3)

-Depression -Adduction -Extorsion

Sympathetic Autonomics of Orbit/Eye: -Same information as another card but with a different image

1. Preganglionic sympathetic cell bodies are located in the lateral horn from T1-T2. 2. Preganglionic sympathetic cell fibers travel within sympathetic chain 3. Postganglionic sympathetic cell bodies are located in the SCG. 4. Postganglionic sympathetic cell fibers travel with the internal carotid nerve and branches of V1

Flow of aqueous humor: 1. Where is it produced? 2. Flows from which chamber to what chamber via what? 3. Drains into which system via what sinus?

1. Produced in posterior chamber by ciliary processes 2.Flows from posterior chamber to anterior chamber via the pupil 3.Drains to venous system via the scleral venous sinus •Scleral venous sinus drains to anterior ciliary veins

In a fully abducted eye, what's the only muscle that can depress the eyeball?

Inferior rectus

Oculomotor nerve (CN III): the superior division innervates what 2 muscles?

LPS, superior rectus

What would you see with CN VI palsy?

•Diplopia •Loss of eye abduction

Orbit: Fats, fascias (4)

- Check ligament of medial rectus muscle -check ligament of lateral rectus muscle - Periorbital fat -fascial sheath of eyeball (Tenon's capsule)

What is action of LPS and superior tarsal portion respectively?

- LPS initially opens the eye -superior tarsal portion of LPS keeps the eye open

What are the actions of inferior oblique? (3)

-Elevation -Abduction -Extorsion

The eyeball is composed of 3 tunics, in addition to what else?

-Lens -Chambers •Anterior & Posterior Chambers: contain aqueous humor •Vitreous Chamber

What is abducens nerve palsy? How does the eyeball rest?

-Paralysis of lateral rectus muscle -Eye rests in adducted position

How would you describe presbyopia and cataracts of the lens, respectively?

-Presbyopia - hardening (loss of elasticity); inability to accommodate (focus on near objects) -Cataracts - protein of the lens aggregate and produce opacity

Which nerve provides vision for the eye?

-SSA -Optic nerves (CN II)

What are the autonomic's of the intraocular eye muscles? (2)

-Sphincter pupillae, ciliary muscle - GVE-P -Dilator pupillae and superior tarsal muscle - GVE-S

What are the 7 bones that contribute to the orbit?

1. Frontal bone 2. Ethmoid bone 3. Lacrimal bone 4. Maxillary bone 5. Sphenoid bone 6. Zygomatic bone 7. Palatine bone

The retina contains the optic disc: 1. Where is it located? 2. You can set of entry for which nerve, artery and vein? 3.T/F: photoreceptor cells are found here

1. Located in posterior pole of globe 2. Site of entry of optic nerve (CN II) and central retinal a. & v. 3. False, no photoreceptive cells here

Parasympathetic Autonomics of Orbit/Eye: -Same information as another card but with a different image

1. Preganglionic parasympathetic cell bodies are located in the Edinger-Westphal nucleus. 2. Preganglionic parasympathetic cell fibers travel with CN III. 3. Postganglionic parasympathetic cell bodies located in ciliary ganglion. 4. Postganglionic parasympathetic cell fibers travel with short ciliary nn (V1).

How many chambers does the eyeball have?

2 aqueous and 1 vitreous

What nerve causes pupil constriction?

CN III

What is extorsion vs intorsion?

Extorsion: superior pole of eyeball rotated laterally Intorsion: superior pole of eyeball rotated medially

What is the flow of tears? (7)

Flow of tears: Lacrimal gland to conjunctival sac to surface of eye to lacrimal papillae with puncta to cannaliculae to lacrimal sac to nasolacrimal duct

Parasympathetics to Ciliary muscle: -Function: -Dysfunction:

Function - accommodation (thickening of lens for near vision) Dysfunction - inability to focus on near objects (presbyopia)

Sympathetics to Superior Tarsal muscle:- Function: -Dysfunction:

Function - assists with elevation of upper eyelid. Dysfunction - ptosis

Sympathetics to Dilator Pupillae muscle: -Function: -Dysfunction:

Function - mydriasis (pupillary dilation) Dysfunction - loss of pupillary dilation; constricted pupil

In a fully adducted eye, what's the only muscle that can elevate the eyeball?

Inferior oblique

The levator palpebrae superioris (LPS) and superior tarsal portion of LPS, are innervated by what, respectively?

Levator palpebrae superioris (LPS) (Skeletal muscle - GSE fibers via CN III) superior tarsal portion of LPS (Smooth muscle - sympathetic innervation)

Extraocular Eye Muscles: Testing Integrity

Only 2 not covered so far: Medial rectus: damage leads to loss of adduction Lateral rectus: damage leads to less of abduction

What 2 things make up the external fibrous tunic? How are these different? (3 for each)

Sclera •Tough, opaque, fibrous layer •Covers posterior 5/6 of globe •Structural support, muscle attachment Cornea •Avascular •Covers anterior 1/6 of globe •Numerous pain receptors

In a fully adducted eye, whats the only muscle that can depress the eyeball?

Superior oblique

What are the symptoms of CN IV palsy? (2)

•Diplopia •Eye will be elevated and adducted, loss of depression when eye is fully adducted

The eyeball is composed of 3 tunics. What are they?

•External fibrous tunic •Middle vascular tunic (uvea) •Inner neural tunic (retina)

How are the maxillary sinus, anterior cranial fossa, and ethmoid sinus located in relation to the orbit bones?

•Maxillary sinus - inferior to orbit •Anterior cranial fossa - superior •Ethmoid sinus - medial

Compare the palpebral conjunctiva and bulbar conjuctiva

•Palpebral conjunctiva - epithelium of internal eyelid •Bulbar conjunctiva - outer epithelium of sclera

What is a clinical correlation with damage to the LPS or superior tarsal portion of LPS?

•Ptosis (drooping of upper eyelid) •Involvement of CN III (loss of LPS) •Horner's syndrome (loss of superior tarsal portion of LPS) •Ptosis, miosis, anhidrosis

The retina contains the macula lutea: -what is this is?

Yellow-pigmented zone 2.5mm lateral to optic disc in

Ocular Reflexes: Pupillary Light Reflex

Afferent nerve - CN II Efferent nerve - CN III

Ocular Reflexes: Accommodation -Review

Afferent nerve - CN II Efferent nerve - CN III Looking from a distant object to a near object (CN II) Ciliary muscles contract, cause rounding of lens (accommodation) (CN III) Pupils constrict (CN III) Eyes adduct (CN III) -Bringing the finger close to the pt's nose

What goes through the following foramina: 1. Anterior ethmoidal foramen (3) 2. Posterior ethmoidal foramen (3) 3. Nasolacrimal canal (1) These foramina are found in which bones respectively?

Anterior ethmoidal foramen: anterior ethmoidal a.v.n. Posterior ethmoidal foramen: posterior ethmoidal a.v.n. Nasolacrimal canal: nasolacrimal duct -Anterior and posterior ethmoidal foramen found on frontal bone -Nasolacrimal canal found on lacrimal bone

Orbit: Clinical Correlation: Blow Out Fracture 1. This fracture is most likely to occur where? 2. Usually occur where on the orbital wall?

Blow Out Fracture - a zygomaticomaxillary fracture or direct flow to the front of the orbit 1.Fractures are most likely to occur at the sutures between the bones 2.Usually occurs at the inferior or medial orbital walls

In the orbit, what are the components of the following cranial nerves: II, III, IV, V1, VI, VII

CN II - SSA CN III - GSE; GVE-P CN IV - GSE CN V1 - GSA CN VI - GSE CN VII - SVE to orbicularis oculi

What nerve innervates a superior oblique muscle

CN IV

What innervates the lateral rectus muscle?

CN VI

What 3 things make up the vascular tunic? Can you describe the choroid portion of this tunic? (3)

Choroid •Highly vascularized, loose CT •Deep to sclera •Provides vascular supply & contains melanocytes which absorb photons of light Iris Ciliary Body

Why would increase intracranial pressure be transmitted to the eye, leading to vision impairment?

Since the eye is derived from neural ectoderm, meninges surround the optic nerve. The increased intracranial pressure will directly compress the optic nerve or indirectly compress the central retinal artery. This can lead to both vision impairment and papilledema (swelling due to compression of central retinal vein) To be clear, vision impairment is due to compression of optic nerve or central retinal artery, while papilledema is due to compression of central retinal vein

Parasympathetics to Sphincter Pupillae muscle: -Function: -Dysfunction:

Function -miosis (pupil constriction). Dysfunction - loss of pupillary constriction; pupil will be dilated.

Parasympathetics to Lacrimal Gland: -Function: -Dysfunction:

Function: tear production Dysfunction: loss or decrease of tear production

Sympathetics to Lacrimal Gland -Function:

Function: unclear...

What are the autonomics of the lacrimal gland? (2)

GVE-P GVE-S (**from different source than intraocular eye muscles)

How would you know if the inferior oblique is impaired?

Inferior oblique can elevate and abduct the eye from primary position. Abduction can also be accomplished by lateral rectus; elevation in the abducted eye can also be accomplished by superior rectus. Thus, if the inferior oblique is impaired, these functions will still exist. However, when the eye is fully adducted, the inferior oblique is the only muscle capable of elevating the pupil. In this position, the superior rectus loses its mechanical advantage. Thus, if there is weakness or loss of elevation in the fully adducted eye, inferior oblique is impaired.

If the eye is already adducted, inferior oblique and superior oblique do what?

Inferior oblique elevates and Superior oblique depresses

How would you know if the inferior rectus is impaired?

Inferior rectus can depress and adduct the eye from primary position. Adduction can also be accomplished by medial rectus; depression in the adducted eye can also be accomplished by superior oblique. Thus, if the inferior rectus is impaired, these functions will still exist. However, when the eye is fully abducted, the inferior rectus is the only muscle capable of depressing the pupil. In this position, the superior oblique loses its mechanical advantage. Thus, if there is weakness or loss of depression in the fully abducted eye, inferior rectus is impaired.

Extraocular Eye Muscles

LR6SO4R3 Abducent nerve (CN VI) - lateral rectus Trochlear nerve (CN IV) - superior oblique Oculomotor nerve (CN III) - levator palpebrae superioris, medial, superior, inferior rectus and inferior oblique Make sure to know which nerve innervates which muscles

Macular degeneration involves loss where in the eye? Are most caused by wet or dry causes? How are these 2 different?

Macular Degeneration involves loss of the center of the field of vision Wet: (10%) Blood vessels from choroid leak into the retina Dry: (90%) Extracellular material (drusden) accumulates behind retina

What goes through the following foramina: 1. Optic canal (2) 2. Superior orbital fissure (5) 3. Inferior orbital fissure (5) These foramina are found on which bone?

Optic Canal: optic n. & ophthalmic a. Superior orbital fissure: CN III, IV, V1, VI, superior ophthalmic v. Inferior orbital fissure: inferior ophthalmic v., infraorbital a.v.n, zygomatic nn. -Found on sphenoid bone

If you're looking at your watch, what is occurring in your eye? -Ciliary muscle -Suspensory ligament -Ciliary processes

-Accomodation Near Vision (Accommodation): -Ciliary muscle contracts and pulls the ciliary body medially and anteriorly and reduces tension on the suspensory ligaments -Less tension on suspensory ligaments results in a rounder and thicker lens -Parasympathetic innervation

Where would you find the anterior chamber, posterior chamber, and vitreous chamber?

-Anterior Chamber - between cornea & iris -Posterior Chamber - between iris and lens -Vitreous Chamber - between lens & posterior surface of the eye

What nerve innervates orbicularis oculi? Damage to his nerve will result in which clinical correlation?

-CN VII -CN VII impairment results in an eyelid that cannot close completely •Inferior eyelid tends to droop downward, resulting in dryness & irritation

Orbit: General features What are Orbital Axes? What are Optical Axes?

-Each orbit is shaped like a pyramid -Orbital axes (long axis through the orbit) are oriented at 45 degrees to one another -Optical axes (long axis through the globe) are parallel to the medial walls

What are the actions of superior rectus? (3)

-Elevation -Adduction -Intorsion

Which nerve (division) provides general sensation for the eye and area around the eye?

-GSA -trigeminal nerve, ophthalmic division (CN V1)

The ophthalmic nerve, gives off a nasociliary, frontal, and lacrimal branches. The lacrimal nerve off the ophthalmic nerve, provides GSA to which 2 regions around the eye?

-Lacrimal gland -Skin of upper lateral eyelid

What are 5 symptoms with CN III palsy?

-Ptosis or complete closure of the eye -Diplopia (double vision) -Eye will be down and out -Dilation of pupil and loss of accommodation

The ophthalmic nerve, gives off a nasociliary, frontal, and lacrimal branches. The frontal nerve off the ophthalmic nerve, provides GSA to which 2 regions around the eye?

-Skin of forehead & upper eyelid -Frontal sinus

What are the 2 muscles that control pupillary diameter and what are the innervated by?

-Sphincter pupillae (parasympathetic innervation, CN III) -Dilator Pupillae (sympathetic innervation)

What are the 6 muscles of the eyeball?

-Superior Rectus -Inferior Rectus -Lateral Rectus -Medial Rectus -Superior Oblique -Inferior Oblique

Venous drainage of the eyeball: 1. What drains directly into the cavernous sinus? 2. What drains the choroid, ciliary body, and Iris

1. Central retinal vein - usually drains directly to cavernous sinus 2.Vorticose veins drain the choroid, ciliary body, and iris

The ciliary body is composed of the ciliary processes and the ciliary muscles 1. What do the ciliary processes do? (2) 2. What do the ciliary muscles do, and what ANS division supplies this muscle?

1. Ciliary processes •Secrete aqueous humor into posterior chamber •Suspensory ligaments to lens (zonular fibers) 2. Ciliary muscle -Parasympathetic innervation -Accommodation

Oculomotor nerve (CN III): 1. the inferior division innervates what 3 muscles? 2. T/F: CN III also carries preganglionic sympathetic fibers to ciliary ganglion

1. Medial rectus, inferior rectus, inferior oblique muscles; 2. False, of course not; it carries preganglionic parasympathetic fibers to the ciliary ganglion. Parasympathetics travel from ciliary ganglion through short ciliary nn. to constrictor pupilae & ciliary mm.

The retina contains the fovea centralis on the macula lutea: 1. How would you describe it, and where is it? 2. T/F: this is a site for the greatest visual acuity; if so, why?

1. Oval depression in center of macula 2. Site of greatest visual acuity due to density of cone cells

Which vein exits the orbit via superior orbital fissure, and drains into the cavernous sinus. Which vein exits orbit via the inferior orbital fissure, and drains into the pterygoid plexus?

1. Superior ophthalmic vein 2. Inferior ophthalmic vein

Clinical correlation: Thrombophlebitits of the eye 1. How does it lead to vision loss?

1. Thrombophlebitis of cavernous sinus may send a clot to the central retinal vein, may lead to vision loss

Clinical correlation: glaucoma 1. What is the cause? 2. Often secondary to what 2 possibilities? 3. Results in what, which can lead to blindness?

1.Caused by excess aqueous humor in the anterior & posterior chambers 2. Often secondary to decreased outflow of aqueous humor (blockage) or from increased production 3.Results in increased IOP, and can cause blindness!

What are the 5 branches of the eye that come off the ophthalmic artery, that we should know?

1.Central retinal artery 2.Ciliary arteries -1.Short Posterior -2.Long Posterior -3.Anterior 3.Lacrimal artery 4.Posterior ethmoidal artery 5.Anterior ethmoidal artery

Orbit: Clinical Correlation: Blow Out Fracture 1. How would somebody get diplopia? 2. How was somebody get enopthalmos?

1.Diplopia - involvement of the inferior rectus muscle 2.Enopthalmos - movement of fat into surrounding spaces of mm. entrapment

Lacrimal apparatus rapid fire: 1. Where will you find the lacrimal gland? 2. Where would you find the lacrimal cannaliculi 3. What does the lacrimal sac do? 4. What does a nasolacrimal duct do?

1.Lacrimal gland - in lacrimal fossa in superolateral orbit 2. Lacrimal cannaliculi - in medial angle of eye •Lacrimal punctum is the opening 3.Lacrimal sac - receives fluid from lacrimal canaliculi 4.Nasolacrimal duct - drains fluid to nasal cavity

From superficial to deep what are the 5 layers of the eyelid?

5 Layers of the Eyelid: 1.Skin 2.Loose CT & Adipose Tissue 3.Muscular layer: orbicularis oculi, levator palpebrae superioris 4.Tarsal Plate (dense CT) 5.Palpebral conjunctiva

How would you know if the superior oblique is impaired?

Superior oblique can depress and abduct the eye from primary position. Abduction can also be accomplished by lateral rectus; depression in the abducted eye can also be accomplished by inferior rectus. Thus, if the superior oblique is impaired, these functions will still exist. However, when the eye is fully adducted, the superior oblique is the only muscle capable of depressing the pupil. In this position, the inferior rectus loses its mechanical advantage. Thus, if there is weakness or loss of depression in the fully adducted eye, superior oblique is impaired.

In a fully abducted eye, what's the only muscle that can elevate eyeball?

Superior rectus

How would you know of the superior rectus is impaired?

Superior rectus can elevate and adduct the eye from primary position. Adduction can also be accomplished by medial rectus; elevation in the adducted eye can also be accomplished by inferior oblique. Thus, if the superior rectus is impaired, these functions will still exist. However, when the eye is fully abducted, the superior rectus is the only muscle capable of elevating the pupil. In this position, the inferior oblique loses its mechanical advantage. Thus, if there is weakness or loss of elevation in the fully abducted eye, superior rectus is impaired. https://www.youtube.com/watch?v=3J2UZiLVZKA

If the eye is already abducted, superior rectus and inferior rectus do what?

Superior rectus elevates and Inferior rectus depresses

Ciliary muscles control the thickness of the lens via which ligaments?

Suspensory Ligaments

Sympathetic Autonomics of Orbit/Eye 1. Preganglionic cell bodies are located where? 2. Preganglionic cell fibers travel with which cranial nerve and synapse onto where? 3. Postganglionic cell bodies are located in which ganglionic? 4. Postganglionic cell fibers distribute via which nerve?

Sympathetic Innervation to superior tarsal and dilator pupillae mm 1.Preganglionic cell bodies - T1-T2 lateral horn 2.Preganglionic cell fibers - travel within sympathetic chain 3.Postganglionic cell bodies - superior cervical ganglion. 4.Postganglionic cell fibers distribute via internal carotid nerve.

What structure contains rods and cones (photoreceptors) which sense photons; while also containing ganglion cells that form the optic nerve?

The Retina

How is the sphincter pupillae arranged in comparison to the dilator pupillae?

The sphincter pupillae is arranged circularly, while a dilator pupillae is arranged radially

T/F: all muscle of the eyeball except for the inferior oblique, originate at the common tendinous ring

True

T/F: the Iris control the amount of light entering the pupil

True, the pupil is just a central aperture where there is no Iris

What is action of the lateral rectus?

Abduction of the eye

What is action a medial rectus?

Adduction on the eye

What is the orbital septum? 1. It's a fibrous membrane that connects what? 2. Anteriorly binds what? 3. What does it help limit the spread of?

Orbital septum - part of the tarsal plate 1.Fibrous membrane that connect the tarsi to the margins of the orbit 2.Anteriorly bounds the orbital fat within the orbit itself 3.Helps limit the spread of infections between the face and orbit

What is trochlear nerve palsy? How does the eyeball rest?

Paralysis of trochlear nerve (superior oblique not working) -Eyeball rest in adducted and elevated position

Lobs

Orbit: •Describe the bones that make up the walls of the orbit; discuss structures which may be involved in fractures of the orbit. Review the foramina of the orbit and structures passing to/from the orbit via these foramina. •Describe the structure and function of the eyelids, conjunctiva, and lacrimal apparatus. •Describe the fasciae and fats of the orbit. •Describe the two muscles associated with the eyelids; how might a patient with paralysis of these muscles present. Globe: •Describe the structure and function of the fibrous tunic of the globe. •Describe the structure and function of the vascular tunic of the globe (choroid, iris, ciliary body). Describe two muscles associated with the iris (sphincter and dilator pupillae) and their innervation; how would a patient would present if either of these muscles was paralyzed? Describe the structure, function, and innervation of the ciliary body; how would a patient present if this structure was injured? •Describe the structure and function of the neural tunic. Review the location & functions of the macula lutea and fovea centralis. •Describe the structure and function of the lens and the eye chambers: anterior, posterior, and vitreous. Discuss glaucoma and it's complications. Extraocular Muscles: •Describe the extraocular eye muscles, including their function and GSE innervation; include a discussion of how the integrity of these muscles is tested clinically. How will nerve palsies present? Blood Supply & Innervation: •Describe the vascular supply of the orbit and eyeball; discuss how thrombophlebitis of the cavernous sinus can lead to slowly progressing vision loss. •Describe the course and components of the optic nerve. •Describe the ophthalmic division of the trigeminal nerve; its course, components, and function. •Describe the parasympathetic and sympathetic inne

Parasympathetic Autonomics of Orbit/Eye: 1. Preganglionic cell bodies are located where? 2. Preganglionic cell fibers travel with which cranial nerve and synapse onto where? 3. Postganglionic cell bodies are located in which ganglionic? 4. Postganglionic cell fibers distribute via which nerve?

Parasympathetic Innervation to Intraocular Eye Muscles 1.Preganglionic cell bodies - Edinger-Westphal nucleus in brainstem 2.Preganglionic cell fibers - travel with CN III 3.Postganglionic cell bodies - ciliary ganglion 4.Postganglionic cell fibers distribute via short ciliary nn.

Summary: Innervation of Orbit/Eye Parasympathetics - Travel with Sympathetics - Travel with GSAs from V1 - Travel with

Parasympathetics - Travel with short ciliary nn. ONLY Sympathetics - Travel with short AND long ciliary nn. GSAs from V1 - Travel with short AND long ciliary nn.

What causes oculomotor nerve palsy? What is this? Lastly, how does the eye rest and why?

Ptosis of upper eyelid (Loss of LPS) Eye rests in abducted & depressed position (all mm. except lateral rectus & superior oblique paralyzed)

Since the lens is transparent, flexible, and biconvex, what are it's 2 functions?

Refraction & accommodation