EYE AND ORBIT Flashcards
a pyramid-shaped bony recess in the anterior part of the skull
orbit
the orbit is lined by a periosteum called the ______
periorbital fascia
seven bones contribute to the framework of each orbit: ______, ______, ______, ______, ______, ______, and ______ bone
maxilla, zygomatic, frontal, ethmoid, lacrimal, sphenoid, palatine
contents of the orbit:
- ______ (organ associated with vision)
- ______ muscles
- ______, their branches, and ganglions that are associated with the eye and orbit
- ______ apparatus
Eye, Extrinsic, Nerves, Lacrimal
Bony boundaries of optic canal
Lesser Wing of Sphenoid
Structures Passing Through the optic canal
Optic Nerve
Ophthalmic Artery (a branch from the
internal carotid artery)
Bony boundaries of superior orbital fissure
Lesser Wing of Sphenoid
Greater Wing of Sphenoid
Structures Passing Through the superior orbital fissure
Ophthalmic Division of Trigeminal Nerve
(lacrimal, frontal, and nasociliary branches)
Oculomotor Nerve
Trochlear Nerve
Abducens Nerve
Superior and Inferior Ophthalmic Veins
Bony boundaries of inferior orbital fissure
Greater Wing of Sphenoid
Maxilla
Palatine Bones
Structures Passing Through the inferior orbital fissure
Zygomatic Nerve (branch of maxillary
division of trigeminal)
Infraorbital Nerve (branch of maxillary
division of trigeminal nerve)
Infraorbital Artery (branch of the
maxillary artery)
Infraorbital Vein (drains into pterygoid
plexus)
Branch of Inferior Ophthalmic Vein
Bony boundaries of supraorbital foramen
Frontal
Structures Passing Through the supraorbital foramen
Supraorbital Nerve (branch of
ophthalmic division of trigeminal)
Supraorbital Artery (branch of the
maxillary artery)
Supraorbital Vein (drains into
pterygoid plexus)
Bony boundaries of inferior groove and canal
Maxilla
Structures Passing Through the inferior groove and canal
Infraorbital Nerve (branch of ophthalmic
division of trigeminal)
Infraorbital Artery (branch of the maxillary
artery)
Infraorbital Vein (drains into pterygoid
plexus)
bony boundaries of zygomatic foramen
Zygomatic
Structures Passing Through the zygomatic foramen
Zygomaticotemporal Nerve (branch of
maxillary division of trigeminal)
Zygomaticofacial Nerve (branch of
maxillary division of trigeminal)
bony boundaries of nasolacrimal canal
Lacrimal
Structures Passing Through the nasolacrimal canal
Nasolacrimal Duct
bony boundaries of anterior ethmoidal foramen
Frontal
Ethmoid
Structures Passing Through the anterior ethmoidal foramen
Anterior Ethmoidal Nerve (branch of
ophthalmic division of trigeminal)
Anterior Ethmoidal Artery (branch of
ophthalmic artery)
Anterior Ethmoidal Vein (drains into
ophthalmic vein)
bony boundaries of posterior ethmoidal foramen
Frontal
Ethmoid
Structures Passing Through the posterior ethmoidal foramen
Posterior Ethmoidal Nerve (branch of
ophthalmic division of trigeminal)
Posterior Ethmoidal Artery (branch of
ophthalmic artery)
Posterior Ethmoidal Vein (drains into
ophthalmic vein)
OSTEOLOGY:
WALLS OF THE ORBIT
SUPERIORLY
Frontal (orbital plate)
Lesser wing of the sphenoid
STEOLOGY:
WALLS OF THE ORBIT
INFERIORLY
Maxilla
Zygomatic
Palatine (orbital process)
OSTEOLOGY:
WALLS OF THE ORBIT
MEDIALLY
Ethmoid (lamina papyracea)
Lacrimal
Sphenoid
Maxilla
OSTEOLOGY:
WALLS OF THE ORBIT
LATERALLY
Zygomatic
Greater wing of the sphenoid
A spherical globe with a diameter of approximately 2.5 cm that lies in the orbit’s anterior portion.
EYE
The eye is Surrounded by a thin capsule called the ______ (______):
•Provides support
•Allows for movement
fascia bulbi, Tenon’s capsule
The eye is Composed of 3 coats:
•______
•______
•______
Sclera, Uveal tract, Retina
what segment of the eye
Filled with aqueous humor
ANTERIOR SEGMENT
what segment of the eye
Separated into anterior and posterior chambers by the iris
ANTERIOR SEGMENT
what segment of the eye
Contains aqueous humor secreted by the ciliary body and drained through a trabeculated network eventually into the superior ophthalmic vein
ANTERIOR SEGMENT
what segment of the eye
Intraocular pressure is measured, normally 10 to 20 mm Hg
ANTERIOR SEGMENT
what segment of the eye
Filled with vitreous fluid
POSTERIOR SEGMENT
what segment of the eye
Called the vitreous cavity
POSTERIOR SEGMENT
The outermost layer, very fibrous
SCLERA
White along the periphery, except for the anterior portion –the cornea, which is transparent
SCLERA
Composed of choroid layer, ciliary body, and iris
UVEAL TRACT
The pigmented vascular layer between the sclera and the retina
Choroid
Extends posteriorly from the region of the optic nerve
anteriorly, where it is continuous with the ciliary body
near the ora serrata (anterior margin of the retina)
Choroid
Located between the choroid and the iris
Ciliary Body
Ring-shaped; has a series of transparent fibers that form the suspensory ligament of the lens
Ciliary Body
With in it is the ciliary muscle, which changes the shape of the lens
Ciliary Body
A thin disc like structure with a central opening–the pupil.
Iris
Separates the aqueous humor in to the anterior chamber (anterior to the iris) and the posterior chamber (between the iris and the lens).
Iris
Contains the sphincter and dilator pupillae muscles, which change the pupil’s shape in response to light.
Iris
Located posterior to the iris.
LENS
A transparent biconcave structure responsible for focusing.
LENS
Connected to the ciliary body by the suspensory ligaments.
LENS
The innermost coat of the eye.
RETINA
Thin and highly vascular.
RETINA
3 areas located on the retina’s posterior portion :
- ______
- ______
- ______
Optic disc, Macula lutea, Fovea centralis
Area where the optic nerve enters the retina is called the “blind spot”.
Optic Disc
Retina’s central artery enters the eye through the ______ and divides into superior and inferior branches.
optic disc
lateral to the optic disc
A depressed, yellow-appearing area that contains the fovea centralis in its center
Macula lutea
area of highest visual acuity and contains high concentration of cone photoreceptors.
Fovea Centralis
is the visual area seen by an eye at a given instant
FIELD OF VISION
is the area seen to the nasal side
NASAL FIELD
is the area seen to the lateral side
TEMPORAL FIELD
The ______ can be divided roughly into an old system to the midbrain and base of the forebrain and a new system for direct transmission of visual signals into the visual cortex located in the occipital lobes.
visual pathways
New System of Visual Pathway
- The visual nerve signals leave the retinas through the ______.
- At the ______, the optic nerve fibers from the nasal halves/field of the retinas cross to the opposite sides, where they join the fibers from the opposite temporal retinas to form the ______.
- The fibers of each optic tract then synapse in the ______.
- From there, geniculocalcarine fibers pass by way of the ______ (also called the geniculocalcarine tract) to the ______ in the calcarine fissure area of the medial occipital lobe.
optic nerves
optic chiasm, optic tracts
dorsal lateral geniculate nucleus of the thalamus
optic radiation, primary visual cortex
New System of Visual Pathway
The ______ lies in the calcarine fissure area, extending forward from the occipital pole on the medial aspect of each occipital cortex. This area is the terminus of direct visual signals from the eyes.
primary visual cortex
New System of Visual Pathway
The ______, also called visual association areas, lie lateral, anterior, superior, and inferior to the primary visual cortex. Secondary signals are transmitted to these areas for analysis of
visual meanings. It has different visual areas that
have specific designations.
Secondary Visual Areas of the Cortex
Old System of Visual Pathway
Visual fibers also pass to several older areas of the brain:
- from the optic tracts to the ______ of the hypothalamus, presumably to control circadian rhythms that synchronize various physiological changes of the body with night and day;
- into the ______ in the midbrain, to elicit reflex movements of the eyes to focus on objects of importance and to activate the pupillary light reflex;
- into the ______, to control rapid directional movements of the two eyes; and
- into the ______ of the thalamus and surrounding basal regions of the brain, presumably to help control some of the body’s behavioral functions.
suprachiasmatic nucleus
pretectal nuclei
superior colliculus
ventral lateral geniculate nucleus
In humans, the ______ is responsible for perception of virtually all aspects of visual form, colors, and other conscious vision.
Conversely, in many primitive animals, even visual form is detected by the ______, using the superior colliculus in the same manner that the visual cortex is used in mammals.
new system, older system
Perhaps the most important movements of the eyes are those that cause the eyes to “______” on a discrete portion of the field of vision.
fix
Fixation movements are controlled by two neuronal mechanisms: ______ and ______.
voluntary, involuntary
______ fixation mechanism — the mechanism that allows a person to move the eyes voluntarily to find the object on which he or she wants to fix the vision.
Voluntary
______ fixation mechanism — the mechanism that holds the eyes firmly on the object once it has been found.
Involuntary
To summarize, posterior “______” occipital cortical eye fields automatically “lock” the eyes on a given spot of the visual field and thereby prevent movement of the image across the retinas.
To unlock this visual fixation, voluntary signals must be transmitted from cortical “______” eye fields located in the frontal cortices.
involuntary, voluntary
In the same manner that a glass lens can focus an image on a sheet of paper, the lens system of the eye can focus an image on the retina. The image is ______ and ______ with respect to the object.
However, the mind perceives objects in the ______ position despite the upside-down orientation on the retina because the brain is trained to consider an inverted image as normal.
inverted, reversed, upright
Extrinsic muscles of the orbit
Levator palpebrae superioris
Superior rectus
Inferior rectus
Medial rectus
Lateral rectus
Superior oblique
Inferior oblique
INTRINSIC MUSCLES OF THE ORBIT
Ciliary
Sphincter pupillae
Dilator pupillae
Origin of Levator palpebrae superiors
Origin: Sphenoid (Lesser wing)
Insertion of Levator palpebrae superioris
Insertion: Skin of the upper eyelid
Actions of Levator palpebrae superioris
Actions: Raises the upper eyelid
Nerve of Levator palpebrae superioris
Nerve: Superior division of the oculomotor, Sympathetic fibers to the superior tarsal muscle (smooth muscle)
Origin of Superior rectus
Origin: Common tendinous ring on sphenoid
Insertion of Superior rectus
Insertion: Superior sclera
Actions of Superior rectus
Actions: Elevation, Adduction, Intorsion
Nerve of Superior rectus
Nerve: Superior division of the oculomotor
Origin of Inferior rectus
Origin: Common tendinous ring on sphenoid
Insertion of Inferior rectus
Insertion: Inferior sclera
Actions of Inferior rectus
Actions: Depression, Adduction, Extorsion
Nerve of Inferior rectus
Nerve: Inferior division of the oculomotor
Origin of Medial rectus
Origin: Common tendinous ring on sphenoid
Insertion of Medial rectus
Insertion: Medial sclera
Actions of Medial rectus
Actions: Adduction
Nerve of Medial rectus
Nerve: Inferior division of the oculomotor
Origin of Lateral rectus
Origin: Common tendinous ring on sphenoid
Insertion of Lateral rectus
Insertion: Lateral sclera
Actions of Lateral rectus
Actions: Abduction
Nerve of Lateral rectus
Nerve: Abducens
Origin of Superior oblique
Origin: Body of sphenoid
Insertion of Superior oblique
Insertion: Superior portion of the posterolateral
sclera
Actions of Superior oblique
Actions: Depression, Abduction, Intorsion
Nerve of Superior oblique
Nerve: Trochlear
Origin of Inferior oblique
Origin: Maxilla (lateral to the lacrimal groove)
Insertion of Inferior oblique
Insertion: Inferior portion of the posterolateral sclera
Actions of Inferior oblique
Actions: Elevation, Abduction, Extorsion
Nerve of Inferior oblique
Nerve: Inferior division of the oculomotor
Location of Ciliary
Location: Muscle fibers in the ciliary body
Innervation of Ciliary
Innervation: Parasympathetics from the oculomotor nerve [III]
Function of Ciliary
Function: Constricts ciliary body, relaxes tension on lens, lens becomes more rounded.
Location of Sphincter pupillae
Location: Circularly arranged fibers in the iris
Innervation of Sphincter pupillae
Innervation: Parasympathetics from the oculomotor nerve [III]
Function of Sphincter pupillae
Function: Constricts pupil
Location of Dilator pupillae
Location: Radially arranged fibers in the iris
Innervation of Dilator pupillae
Innervation: Sympathetics from the superior cervical ganglion (T1)
Function of Dilator pupillae
Function: Dilates pupil
ORBITAL INNERVATION
Sensory
2 Major Types
- ______ (Special Somatic Afferent) via the optic nerve
- ______ (General Somatic Afferent) via the ophthalmic (and some maxillary) division of
the trigeminal nerve
Vision, General Sensation
ORBITAL INNERVATION
Motor
2 Major Types
- Motor to the ______ (General Somatic Efferent) via the oculomotor, trochlear, and abducens nerve
- Autonomics to the ______ of the eye (General Visceral Efferent) via:
Parasympathetics associated with the ciliary ganglion
Sumpathetics associated with the superior cervical ganglion
extraocular muscles, intrinsic muscles
Cranial Nerves
5 cranial nerves provide innervation to the orbit:
______ - vision
______ - extraocular motor and autonomics to the intrinsic muscles of the eye
______ - extraocular motor
______ - general sensation
______ - extraocular motor
Optic
Oculomotor
Trochlear
Trigeminal
Abducens
- This division, being a branch of the trigeminal nerve, is sensory in function
- Arises from the main nerve in the middle cranial fossa
- Passes anterior on the lateral wall of the cavernous sinus immediately inferior to the oculomotor and trochlear nerve, but superior to the maxillary division of the trigeminal
- Before entering the orbit, it gives rise to a small tentorial branch
- Immediately before entering the orbit, through the superior orbital fssure, it divides into 3 major branches: lacrimal, frontal, and nasociliary nerve
GENERAL SENSATION
OPHTHALMIC DIVISION OF THE TRIGEMINAL NERVE
- From the ophthalmic division of the trigeminal nerve
- Smallest branch of the ophthalmic division of the trigeminal nerves
- Passes anteriorly to enter the orbit through the superior orbital fissure
- In the orbit, it travels on the superior border of the lateral rectus muscle with the lacrimal artery
- Before reaching the lacrimal gland, it communicates with the zygomatic branch of the maxillary division of the trigeminal to receive autonomic nervous fibers
- Enters the lacrimal gland and supplies it and the conjunctiva before piercing the orbital septum to supply the skin of the upper eyelid
LACRIMAL NERVE
- From the ophthalmic division of the trigeminal nerve
- Largest branch of the ophthalmic division of the trigeminal nerve
- Passes anteriorly to enter the orbit through the superior orbital fissure
- In the orbit it passes anteriorly between the periosteum of the orbit and the levator palpebrae superioris muscle
- About halfway in the orbit, it divides into its 2 terminal nerves:
supraorbital nerve
supratrochlear nerve
FRONTAL NERVE
- From the frontal nerve (ophthalmic division of the trigeminal nerve)
- Passes between the levator palpebrae superioris m. and the periosteum of the orbit
- Continues anteriorly to the supraorbital foramen (notch)
- At the level of the supraorbital margin, it sends nerve supply to the frontal sinus and ascends superiorly along the scalp
- Divides into medial and lateral branches, which travel up to the vertex of the scalp
SUPRAORBITAL NERVE
- From the frontal nerve (ophthalmic division of the trigeminal nerve)
- Once the supratrochlear artery joins it within the orbit, it continues to pass anteriorly toward the trochlear
- In the trochlear region, it often supplies the frontal sinus before exiting the orbit
- Ascends along the scalp, at 1st deep to the musculature in the region before piercing them to reach the cutaneous innervation along the scalp
SUPRATROCHLEAR NERVE
- From the ophthalmic division of the trigeminal nerve
- Passes anteriorly to enter the orbit through the superior orbital fissure
- Enters the orbit lateral to the optic nerve
- Travels across the optic nerve anteriorly and medially to lie between the medial rectus and the superior oblique muscle along the medial wall of the orbit
- All along its path, it gives rise to other nerves, including the sensory root of the ciliary ganglion, and the long ciliary and posterior ethmoidal nn., until terminating into the anterior ethmoidal and infratrochlear nerve near the anterior ethmoidal foramen
NASOCILIARY NERVE
- From nasociliary nerve
- Travels anteriorly on the lateral side of the optic nerve to enter the ciliary ganglion
- Carries general sensory fibers, which are distributed by the short ciliary nerve
SENSORY ROOT OF THE CILIARY GANGLION
- From ciliary ganglion
- Arises from the ciliary ganglion to travel to the posterior surface of the eye
- Supplies the sensory fbers to the eye and helps carry the postganglionic parasympathetic fbers to the sphincter pupillae and the ciliary muscle
Short ciliary
- From nasociliary nerve
- There are 2 to 4 branches that travel anteriorly to enter the posterior part of the sclera of the eye
Long ciliary
- From nasociliary nerve
- Travels deep to the superior oblique m. to pass through the posterior ethmoidal foramen
- Supplies the sphenoid sinus and the posterior ethmoidal sinus
Posterior ethmoidal
- From nasociliary nerve
- Arises on the medial wall of the orbit
- Enters the anterior ethmoidal foramen and travels through the canal to enter the anterior cranial fossa
- Supplies the anterior and middle ethmoidal sinuses before entering and supplying the nasal cavity
- Terminates as the external nasal nerve on the face
Anterior ethmoidal
- From nasociliary nerve
- One of the terminal branches of the nasociliary nerve
- Passes anteriorly on the superior border of the medial rectus muscle
- Passes inferior to the trochlea toward the medial angle of the eye
- Supplies the skin of the eyelids and bridge of the nose, the conjunctiva, and all of the lacrimal structures
INFRATROCHLEAR NERVE
- Travels along the lateral wall of the cavernous sinus
- Before exiting the middle cranial fossa, it gives off a meningeal branch that innervates the dura mater Passes from the middle cranial fossa into the pterygopalatine fossa via the foramen rotundum Within the pterygopalatine fossa, it gives rise to 4 branches: posterior superior alveolar nerve, zygomatic nerve, ganglionic branches, and infraorbital nerve
- The zygomatic and infraorbital continue within the orbit
GENERAL SENSATION
MAXILLARY DIVISION OF THE TRIGEMINAL NERVE
- From maxillary division of the trigeminal nerve
- Enters the orbit via the inferior orbital fissure
- Within the orbit, it divides into the zygomaticotemporal and zygomaticofacial branches, which exit the orbit along the lateral wall via 1 or 2 zygomatic foramina
ZYGOMATIC NERVE
- From maxillary division of the trigeminal nerve
- Considered the continuation of the maxillary division of the trigeminal nerve
- Passes through the inferior orbital fssure to enter the orbit
- Passes anteriorly through the infraorbital groove and infraorbital canal and exits onto the face via the infraorbital foramen
- Within the infraorbital canal, it gives rise to the anterior superior alveolar and middle superior alveolar nn.
- Once the infraorbital nerve exits onto the face, it divides into 3 terminal branches:
Inferior palpebral supplies the skin of the lower eyelid and conjunctiva
Nasal supplies the skin of the ala of the nose
Superior labial supplies the skin of the upper lip
INFRAORBITAL NERVE
- From the Ventral surface of the midbrain.
- It innervates 4 of the extraocular muscles superior rectus, inferior rectus, medial rectus, and inferior oblique mm-as well as the levator palpebrae superioris muscle.
- It also provides parasympathetic innervation to the intrinsic muscles of the eye.
- passes anterior on the lateral wall of the cavernous sinus immediately superior to the trochlear nerve.
- Immediately before entering the orbit, it divides into superior and inferior divisions, both enter the orbit through the superior orbital fissure.
OCULOMOTOR NERVE
GENERAL MOTOR
- Enters the orbit via the superior orbital fissure
- Travels superior to the optic nerve to enter the inferior border of the superior rectus muscle.
- Passes through the superior rectus to give rise to a branch that enters the inferior surface of the levator palpebrae superioris muscle.
SUPERIOR DIVISION OF THE OCULOMOTOR
GENERAL MOTOR
- Enters the orbit via the superior orbital fissure.
- It immediately divides into 3 muscular branches that enter:
The lateral surface of the medial rectus
The superior surface of the inferior oblique
The superor surface of the inferior rectus - Gives rise to the parasympathetic root of the ciliary ganglion
INFERIOR DIVISION OF THE OCULOMOTOR
GENERAL MOTOR
- From the dorsal surface of the midbrain.
- Innervates the superior oblique
- Passes anterior on the lateral wall of the cavernous sinus.
- Immediately inferior to the oculomotor nerve.
- Enters the orbit via the superior orbital fissure and immediately enters the superior oblique to innervate it
TROCHLEAR NERVE
GENERAL MOTOR
- From the ventral surface of the pons.
- Travels anteriorly within the cavernous sinus beside the internal carotid artery.
- Enters the orbit via the superior orbital fissure
- Travels anteriorly to enter the medial surface of the lateral rectus to innervate it.
ABDUCENS NERVE
GENERAL MOTOR
- It is found in Edinger- Westphal nucleus.
- It can be characterized as a collection of nerve cell bodies located in the midbrain.
- Arising from the Edinger-Westphal nucleus in the midbrain from the oculomotor nerve.
- Oculomotor nerve passes anteriorly on the lateral wall of the cavernous sinus immediately superior to the trochlear nerve.
- Immediately before entering the orbit, the nerve divides into the superior and inferior divisions Both the superior and inferior divisions of the oculomotor enter the orbit through the superior orbital fissure.
- Preganglionic parasympathetic fibers travel in the inferior division.
- A small parasympathetic root passes from the inferior division of the oculomotor to the ciliary ganglion, carrying the preganglionic parasympathetic fibers.
PREGANGLIONIC NEURON
PARASYMPATHETICS OF THE EYE
- Found in Ciliary ganglion.
- Located anterior to the optic foramen between the optic n and the lateral rectus
POSTGANGLIONIC NEURON
PARASYMPATHETICS OF THE EYE
3 roots connect to the cilia the ganglion
- ______ from the ophthalmic division of the trigeminal, which carries general sensation fibers to the eye via the short ciliary nerve.
- ______ from the inferior division of the oculomotor, carrying preganglionic parasympathetic fibers to the ganglion
- ______ that arises from the postganglionic sympathetic fibers, which were carried by the internal carotid artery.
Sensory root, Parasympathetic root, Sympathetic root
- The short ciliary nerve. Usually number about 8 Short ciliary nerve. arise from the ciliary ganglion to enter the posterior portion of the eye fibers from all 3 roots pass through the ciliary ganglion and short ciliary nerve to enter the eye
- Only the parasympathetic fibers synapse in the ciliary ganglion.
- The postganglionic neuron arises in the ciliary ganglion, following a synapse with the preganglionic parasympathetic fibers. Travel through the short ciliary nerve to enter the eye’s posterior portion
- Innervates the sphincter pupillae muscle and ciliary muscle.
POSTGANGLIONICNEURON
PARASYMPATHETICS OF THE EYE
- Its cell body is called Intermediolateral horn nucleus.
- This cell body is a collection of nerve cell bodies located in the lateral horn nucleus of the spinal cord between spinal segments Tl and 13. (and possibly T4).
- Preganglionic neuron will arise from the intermediolateral horn nuclei from 11 to 13 (or 14)
- Travel through the ventral root of spinal cord to the spinal nerve the
- Enter the sympathetic chain via a white ramus communicans.
- Once in the sympathetic chain, the preganglionic fibers for the eye will ascend and synapse with postganglionic fibers in the superior cervical ganglion.
PREGANGLIONIC NEURON
ANATOMIC PATHWAY FOR SYMPATHETICS OF THE EYE
- It’s cell body is called Superior cervical ganglion.
- The Superior cervical ganglion is a collection of nerve cell bodies located in the superior cervical ganglion, which is located at the base of the skull
- will arise in the superior cervical ganglion
- Postganglionic fibers will follow the internal carotid a on the internal carotid plexus
- As the internal carotid artery, nears the orbit, the postganglionic fibers branch from the internal carotid plexus and follow various structures that connect to the eye, such as the ophthalmic artery and its branches, and the long ciliary nerve that arise from the ophthalmic division of the trigeminal nerve.
- In the eye, the postganglionic fibers innervate:
dilator pupillae muscle
POSTGANGLIONIC NEURON
ANATOMIC PATHWAY FOR SYMPATHETICS OF THE EYE
WHAT ARTERY?
Supply: Internal carotid a.
Course:
- Enters the orbit through the optic foramen immediately inferior and lateral to the optic n.
- Crosses the optic n. to reach the medial part of the orbit
- While in the orbit, the artery gives rise to a series of arteries that supply the orbit and associated structures
- The terminal aa. of the ophthalmic a. anastomose along the scalp and face with the superficial temporal, facial, and infraorbital branches of the maxillary
Artery: Ophthalmic
WHAT ARTERY?
Source: Ophthalmic a.
Course:
- Arises near the optic foramen
- 1 of the ophthalmic’s largest branches
- Follows the lacrimal n. along the superior border of the lateral rectus m. of the eye to reach and supply the lacrimal gland
- Gives rise to a series of terminal branches, such as the lateral palpebral, that supply the eyelids and conjunctiva
- Gives rise to a zygomatic branch that then gives rise to the zygomaticotemporal and zygomaticofacial aa.
- Supply those regions of the face
Artery: Lacrimal
WHAT ARTERY?
Source: Ophthalmic a.
Course:
- It exits the orbit at the medial angle accompanied by supratrochlear n.
- Ascends on the scalp, anastomosing with the supraorbital a. and supratrochlear a. from the opposite side
Artery: Supratrochlear
WHAT ARTERY?
Source: Ophthalmic a.
Course:
- Branches from the ophthalmic a. as it passes the optic n.
- Passes on the medial side of the levator palpebrae superioris and superior rectus mm. to join the supraorbital n.
- Passes through the supraorbital foramen (notch) and ascends superiorly along the scalp
- Anastomoses with the supratrochlear a. and superficial temporal a.
Artery: Supraorbital
WHAT ARTERY?
Source: Ophthalmic a.
Course:
- Travels with the nerve through the anterior ethmoidal canal to supply the anterior and middle ethmoidal sinuses
- Continues to give rise to a meningeal branch and nasal branches that supply the lateral wall and septum of the nose
- Then gives rise to the terminal external nasal branch that supplies the external nose
Artery: Anterior ethmoidal
WHAT ARTERY?
Source: A terminal branch of the anterior ethmoidal a.
Course:
- Supplies the area along the external nose at the junction between the nasal bone and the lateral nasal cartilage
Artery: External nasal
WHAT ARTERY?
Source: Ophthalmic a.
Course:
- Travels through the posterior ethmoidal canal to supply the posterior ethmoidal sinus
- Gives rise to meningeal and nasal branches that anastomose with branches of the sphenopalatine
Posterior ethmoidal
WHAT ARTERY?
Source: Ophthalmic a. of the internal carotid
a.
Course:
- Arise near the trochlea and exit the orbit to pass along the upper and lower eyelids
- These arteries anastomose with the other arteries supplying the face in the region
Artery: Medial palpebral (superior and inferior)
WHAT ARTERY?
Source: 1 of the ophthalmic a’s terminal
branches
Course:
- Exits the orbit along the superomedial border along with the infratrochlear n.
- Supplies the area along the bridge of the nose
Artery: Dorsal nasal (infratrochlear)
WHAT ARTERY?
Source: Ophthalmic a. from the internal carotid a.
Course:
- Supply the extraocular muscles of the orbit
Artery: Muscular
WHAT ARTERY?
Source: Muscular branches from the ophthalmic a.
Course:
- Pass anteriorly to the anterior surface of the eye following the tendons of the extraocular muscles
Artery: Anterior ciliary
WHAT ARTERY?
Source: Ophthalmic a. from the internal carotid a
Course:
- Usually 6 to 10 arise
- Travel anteriorly around the optic n. to enter the posterior portion of the eye
Artery: Short posterior ciliary
WHAT ARTERY?
Source: Ophthalmic a. from the internal carotid a.
Course:
- Usually 2 arise
- Travel anteriorly to enter the posterior portion of the eye near the optic n.
Artery: Long posterior ciliary
WHAT ARTERY?
Source: Ophthalmic a. from the internal carotid a.
Course:
- Branches from the ophthalmic a. early on its entrance into the orbit
- Follows the optic n. and enters the nerve about halfway into the orbit
- Supplies the retina
Artery: Central a. of the retina
WHAT ARTERY?
Source: 1 of 2 terminal branches of the external carotid a.
Course:
- Gives rise to a series of branches
- Only the infraorbital branch supplies the orbit
Artery: Maxillary
WHAT ARTERY?
Source: Maxillary a.
Course:
- Once the infraorbital exits the infraorbital foramen, the inferior palpebral a. supplies the lower eyelid
- Supplies some muscles along the floor of the orbit near the inferior orbital canal
Artery: Infraorbital
WHAT VEIN?
Course:
- Begins on the forehead, where it communicates with the superficial temporal v.
- Passes inferiorly superficial to the frontalis m. and joins the supratrochlear v. at the medial angle of the orbit to form the angular v.
Vein: Supraorbital
WHAT VEIN?
Course:
- Begins on the forehead, where it communicates with the superficial temporal v.
- Passes inferiorly along the forehead, parallel with the vein of the opposite side
- At the medial angle of the orbit, the supratrochlear joins the supraorbital v. to form the angular v.
Vein: Supratrochlear
WHAT VEIN?
Course:
- Forms from the confluence of the supraorbital and supratrochlear vv. along the medial part of the eye
- Travels along the lateral aspect of the nose to become the facial v.
Vein: Angular
WHAT VEIN?
Course:
- Begins as the angular v.
- Passes inferiorly along the side of the nose, receiving the lateral nasal v.
- Continues posteroinferiorly across the angle of the mouth to the cheek receiving the superior and inferior labial vv.
- While passing toward the mandible, the it connects to the pterygoid plexus
- In the submandibular triangle it joins the anterior branch of the retromandibular to form the common facial v.
- it has no valves that can allow blood to backflow
Vein: Facial
the superficial veins
Supraorbital
Supratrochlear
Facial
WHAT VEIN?
Course:
- A reticulated venous structure located on the lateral aspect of the body of the sphenoid bone
- Drain posteriorly into the superior and inferior petrosal sinuses
- Receives blood from the superior and inferior ophthalmic vv.
- Oculomotor and trochlear nn. and ophthalmic and maxillary divisions of the trigeminal n. lie along the lateral wall of the sinus
- Abducens n. and internal carotid a. lie in the sinus
Vein: Cavernous sinus
WHAT VEIN?
Course:
- An extensive network of veins that parallels the 2nd and 3rd parts of the maxillary a.
- Receives branches that correspond to the same branches of the maxillary a.
- Tributaries to the pterygoid plexus eventually converge to form a short maxillary v.
- Communicates with the cavernous sinus, pharyngeal venous plexus, facial v. via the deep facial v., and ophthalmic vv.
Vein: Pterygoid plexus
the deep veins
Cavernous sinus
Pterygoid plexus
WHAT VEIN?
Course:
- Receives blood from the roof of the orbit and the scalp
- Travels posteriorly to communicate with the cavernous sinus
Vein: Superior ophthalmic
WHAT VEIN?
Course:
- Receives blood from the midface via the lower eyelid, lateral side of the nose, and the upper lip
- Eventually communicates with the pterygoid plexus of vein
Vein: Infraorbital
WHAT VEIN?
Course:
- Receives blood from the floor of the orbit
- Often splits into 2 branches
- 1 branch travels posteriorly with the infraorbital v. that passes through the inferior orbital fissure to communicate with the pterygoid plexus
- The other branch travels posteriorly to communicate directly with the superior ophthalmic v. in the superior orbital fissure, or it will pass through the fissure to communicate with the cavernous sinus
Vein: Inferior ophthalmic
the communicating veins
Superior ophthalmic
Infraorbital
Inferior ophthalmic
It is composed of the following: the Lacrimal gland, the Lacrimal canaliculi, the Lacrimal sac, and the Nasolacrimal duct. It also secretes and drains all tears
LACRIMAL APPARATUS
- Located in the anterolateral part of the orbit
- Secretes serous uid
- Divided into 2 parts by the lateral tendon of the levator palpebrae superioris m.
- Tear formation and absorption
- Tears coat the external surface of the eye to prevent drying, act as a lubricant, and contain bactericidal enzymes
- With blinking, tears are carried across the eye to collect near the medial canthus
- Tears enter through the lacrimal puncta into the lacrimal canaliculi
- Lacrimal canaliculi carry the tears to the lacrimal sac
- Lacrimal sac carries the tears inferiorly through the nasolacrimal duct, which terminates in the inferior meatus
Lacrimal gland
- Because of the close proximity of the oculomotor, trochlear, and abducens nerves to blood vessels supplying the brain, aneurysms along these vessels may lead to a paralysis of the muscles that they innervate.
- Commonly affected vessels include the basilar, posterior cerebral, and posterior communicating arteries
- NEUROMUSCULAR DISORDERS
- ABDUCENS PALSY
- Affected eye turn medially
- May be 1st m an infestation of in tracavern ous carotid aneurysm
- Pain above eye or on side of face may be secondary to trigeminal (V) nerve involvement
- OCULOMOTOR PALSY
- Ptosis; eye turns laterally and inferiorly; pupil dilated
- Common ending with ______, especially carotid–posterior communicating artery
aneurysms
CEREBRAL ANEURYSM
- Damage to the optic nerve often due to increased intraocular pressure.
- Intraocular pressure will rise if the normal cycle of aqueous humor fluid production and absorption is disturbed so that the amount of fluid increases. This condition is glaucoma and can lead to a variety of visual problems including blindness, which results from compression of the retina and its blood supply.
GLAUCOMA
TYPES OF GLAUCOMA:
OPEN ANGLE GLAUCOMA
CLOSED ANGLE GLAUCOMA
- The most common form of Glaucoma
- Gradual and can result in gradual loss of vision
- Intraocular pressure elevates owing to insufficient drainage within the eye’s canal system, located in the angle of the anterior chamber of the anterior segment.
- Various medications are successful in treating this form
OPEN ANGLE GLAUCOMA
- Result of an anatomic blockage of the canal system at the angle of the anterior chamber of the anterior segment.
- Example: When the iris opens the pupil very wide with consequent closure of the angle, intraocular pressure can rise quickly if blockage occurs as an abrupt event.
CLOSED ANGLE GLAUCOMA
- Pathologic changes to the retina resulting from damage to the blood vessels in the retina due to diabetes
- It can occur all people with diabetes (Type 1 and 2)
- It is an eye condition that can cause vision loss and blindness in people who have diabetes, as it affects blood vessels in the retina.
- It can lead to other serious eye conditions like Diabetic Macular Edema ((DME), Neovascular Glaucoma and Retinal Detachment.
DIABETIC RETINOPATHY
- The early stages of diabetic retinopathy usually don’t have any symptoms. Some people notice changes in their vision, like trouble reading or seeing faraway objects. These changes may come and go.
- In later stages of the disease, blood vessels in the retina start to bleed into the ______ (gel-like fluid that fills your eye). If this happens, you may see dark, floating spots or streaks that look like cobwebs. Sometimes, the spots clear up on their own - but it’s important to get treatment right away. Without treatment, scars can form in the back of eye. Blood vessels may also start to bleed again, or the bleeding may get worse.
vitreous
A series of refractive disorders of the eye that cause blurring of the image on the retina.
AMETROPIAS
TYPES OF AMETROPIAS:
MYOPIA
HYPEROPIA
ASTIGMATISM
- Image is focused anterior to the retina.
- Commonly referred to as nearsightedness.
MYOPIA
- Image is focused posterior to the retina.
- Commonly referred to as farsightedness.
HYPEROPIA
A nonspherical eye allows the parts of the image to focus at multiple locations, rather than in a single area.
ASTIGMATISM
The primary detection of most ametropias is possible using a vision test with a simple ______. The patient is measured for visual acuity monocularly with no lens in place. The procedure is then repeated with a pinhole. An improvement in visual acuity with the pinhole over the unaided values indicates the presence of ametropia.
pinhole aperture
The retina is composed of two layers (1) an ______ retina and (2) an ______ retina.
outer pigmented, inner sensory
The ______ retina, with the choroid, keeps light from reflecting back into the eye.
pigmented
The ______ retina contains photoreceptor cells as well as numerous interneurons.
sensory
There are three types of cones, each sensitive to a different color: ______, ______, or ______.
blue, green, red
When a single group of color receptive cones is missing from the eye, the person is unable to distinguish some colors from others. If either of these two cones is missing, the person cannot use this mechanism for distinguishing these four colors; the person is especially unable to distinguish red from green and is therefore said to have ______ color blindness.
red-green
______ – person with loss of red cones; the overall visual spectrum is noticeably shortened at the long wavelength end because of a lack of the red cones.
Protanope
______ – a color-blind person who lacks green cones; this person has a perfectly normal visual
spectral width because red cones are available to detect the long wavelength red color.
Deuteranope
