ORBIT Flashcards by Iseoluwa Ojo

Shape of the orbit

pyramidal

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Each orbit is a——-sided—— with apex directed—- at the—— and base directed—-,represented by the——

four

pyramid

behind

optic canal

forward

orbital margin

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The medial walls of two orbits are—— to each other but the lateral walls are——- to each other

parallel

set at right angle

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The long axis of each orbit (——axis) passes—— and——-

orbital

backwards

medially

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distance between the 2 medial walls of the orbit is——

2.5cm

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optic fiber is myelinated or unmyelinated?

Myelinated

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Thinnest and thickest walls of the orbit are?

Medial

Lateral

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Medial wall of the orbit is formed by???

Frontal process of maxilla.

Lacrimal process of maxilla.
Orbital plate of ethmoid
Body of sphenoid.

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Lateral wall of the orbit is formed by???

Orbital surface of the zygomatic bone in front

-Orbital surface of greater wing of sphenoid behind.

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Floor of the orbit is formed by???

Orbital surface of the body of maxilla

Orbital surface of the zygomatic bone, anterolaterally.
Orbital process of the palatine bone, posteromedially.

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Roof of the orbit is formed by???

Orbital plate of the frontal bone in front

-Lesser wing of the sphenoid behind.

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List two features of Medial wall of the orbit

Lacrimal fossa

Anterior and posterior ethmoidal foramina

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Lacrimal fossa Is bounded in front by the—— of —- and behind by the——- of the—- bone.

anterior lacrimal crest

maxilla

posterior lacrimal crest

lacrimal

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The lacrimal fossa communicates with the nasal cavity through———.

nasolacrimal canal

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The lacrimal fossa and nasolacrimal canal contain—- and——, respectively.

lacrimal sac

nasolacrimal duct

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Anterior and posterior ethmoidal foramina lie at the———

junction between medial wall and the roof of the orbit.

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List the two features of the Lateral wall of the orbit

Zygomatic foramen

Whitnall’s tubercle

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—- and —- can pass through the Zygomatic foramen

zygomaticofacial and zygomaticotemporal nerves.

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Whitnall’s tubercle is a—— just behind the ——-and slightly—— the———

small bony tubercle

lateral orbital margin

below

frontozygomatic suture.

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List the two features of the Floor of the orbit

Infraorbital groove and canal

Small rough impression in anteromedial angle for origin of inferior oblique muscle.

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Route that leads to the Infraorbital foramen.

Originating from the ——the ——is the—— part of the IOC/G. It is followed by the —-which is covered by the—— and terminates at the infraorbital foramen

inferior orbital fissure

infraorbital groove

posterior

infraorbital canal

orbital floor

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Roof Presents three features. List them and which part of the roof they can be found

Fossa for lacrimal gland in the anterolateral part

Trochlear notch or spine at the anteromedial angle

Optic canal at the extreme posterior part of the roof.

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The trochlea of——muscle is a—— structure in the eye

-The—— of the ——muscle passes through it.

superior oblique

pulley-like

tendon

superior oblique

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The apex of the orbit Lies at the—- end of the orbit and is formed by——
-More precisely it is formed by the—— between—— and——

posterior

sphenoid

centre of the bony bridge

optic canal

superior orbital fissure.

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Base of the orbit is Open and—in shape

quadrangular

Supraorbital margin formed by the—— bone and presents a notch called the—— notch or foramen at the junction of———

frontal supraorbital its lateral two-third and medial one-third

Infraorbital margin of the orbit is formed by the—- bone—- and—-bone —— -it is continuous with—— crest___

zygomatic; laterally maxilla; medially anteriorlacrimal medially

——-orbital margin is ill-defined

Medial orbital margin

Medial orbital margin is formed by the——- bone—— and—— of the ——process of—— ——

frontal; above lacrimal crest frontal maxilla below

Lateral orbital margin is formed by ——- above and—— below

zygomatic process of the frontal bone frontal process of the zygomatic bone

The margins of the orbit are readily palpable in vivo. | T/F

The orbital margins provide a fair bony protection to the eye except at the——- margin.

lateral

Protective eye guards don’t permit good peripheral vision.. | T/F

``` RELATIONS OF ORBIT -Above ——-and——— -Lateral ——-and ——-behind. -Below ——— -Medial ———- ```

Anterior cranial fossa; frontal air sinus (usually). Temporal fossa in front; middle cranial fossa Maxillary air sinus Ethmoidal air sinuses.

ORBITAL FASCIA aka——- - lines the ——-of the orbit - forms a——- -shaped fascial sheath that———

PERIORBITA bony boundaries funnel encloses the orbital contents

ORBITAL FASCIA is loosely attached to the bones. | T/F

ORBITAL FASCIA can be easily stripped off especially from——- and ——-of the orbit.

roof medial wall of

At the—- and superior orbital fissure, periorbita becomes continuous with the periosteum lining the—— of the skull (called the ——).

optic canal interior endocranium

At the——- fissure and——, periorbita becomes continuous with the periosteum covering the——- surface of the skull (called the ——)

infraorbital orbital margins external; periosteum

——nerve and vessels and—— nerve lie outside the orbital periosteum, hence—— in the contents of the orbit.

Infraorbital zygomatic not included

EXTRAOCULAR MUSCLES are classified into two groups:—- and___.

voluntary ;involuntary

There are ——-VOLUNTARY extraocular MUSCLES.—— muscles move the eyeball and—- muscle moves the——

seven six one upper eyelid.

List the voluntary extraocular muscles moving the eyeball

Four recti muscles - Superior rectus - Inferior rectus - Medial rectus - Lateral rectus. Two oblique muscles - Superior oblique - Inferior oblique.

The voluntary extraocular muscle which moves the upper eyelid is called———

levator palpebrae superioris

There are ——-INVOLUNTARY extraocular MUSCLES

three

List the INVOLUNTARY extraocular MUSCLES

Orbitalis Superior tarsal Inferior tarsal

Another name for superior tarsal is ——-

Muller’s muscle

All the recti muscles of the eye arise from the——

corresponding margins of the common tendinous ring.

——-rectus arises by two heads.

lateral

The common tendinous ring encloses the optic canal and—— part of the——-

middle superior orbital fissure.

common tendinous ring is attached medially to —— of the orbit and laterally to a small tubercle (tubercle of ——) on the—— border of ——

apex Zinn lower superior orbital fissure.

All the recti muscles of the eye are inserted into—— little posterior to the——- in front of the——- of the eyeball.

sclera limbus equator

Limbus of the eyeball is also know as——?

corneoscleral junction

``` Average distance of the recti muscles from limbus is: Medial rectus -mm Inferior rectus— mm Lateral rectus—- mm Superior rectus —-mm ```

5mm 6 7 8

Superior oblique Origin: -from——— that’s superomedial to the—— Insertion - into——;—— the equator - between—- and—- rectus

body of Sphenoid optic canal sclera; behind superior; lateral

Inferior oblique Origin: -from rough impression in—- part of the—— of the orbital Cavity,—— to lacrimal groove Insertion -into—- ;—- the equator

anteromedial; floor; lateral sclera; behind

Between superior and inferior oblique muscles of the eye, whose insertion point is lower and which is more posterior

Lower-inferior oblique | More back-inferior oblique

Elevation and depression of the eyeball occurs around the——- axis passing through the equator. Adduction and abduction of the eyeball occurs around the——- axis passing through the equator. Rotation (torsion) of the eye occurs around the——- axis

transverse vertical anteroposterior

When —- o’clock position of the cornea rotates—-, it is called—— and when it rotates—-, it called——.

12 medially intorsion laterally extorsion

``` Actions of : Superior rectus (SR) of the eye is ——-, ——-, and——. ``` Superior oblique (SO): ——, ——, and——.

elevation adduction intorsion depression abduction intorsion

``` Actions of : Inferior rectus (IR) of the eye is ——, ——, and—— ``` . Inferior oblique (IO): ——, ——, and——.

depression ;adduction;extorsion elevation ; abduction; extorsion

Action of : Medial rectus (MR) of the eye is—— Lateral rectus (LR): ———.

adduction. abduction

The fascia bulbi - aka—— - is a ——that envelops the—- - extends from—- to the—— - It is separated from the sclera by the—- - forms a socket for the eyeball to facilitate—— - It separates the eyeball from——- - pierced by—— and —— muscles - pierced by—— nerves and vessels around entrance of optic nerve

``` Tenon’s capsule loose membranous sheath ; eyeball optic nerve; sclerocorneal junction. episcleral space. free ocular movements. orbital fat 4Recti,2oblique ciliary ```

Lacrimal gland: exocrine or endocrine??

Exocrine

LACRIMAL GLAND is a—— type of exocrine gland

tubulo-acinar

LACRIMAL GLAND secretes——-. | And consists of two parts: —- and—-.

watery lacrimal fluid orbital palpebral

The orbital part of the lacrimal gland is located in the—— on the—- part of the—- of the orbit - palpebral part is located in—- part of the——

lacrimal fossa; anterolateral; roof lateral; upper eyelid

ORBITAL FAT | -It fills up the space between the—-, ——, and——- muscles.

eyeball optic nerve cone of four rectus

Orbital fat serves as a cushion to stabilize the eyeball during its movements. T/F

Lymphatic drainage of the eye?

There are no lymphatics in the eyeball.!!!!!

Occulomotor nerve has —- divisions?

The—- divisions of oculomotor nerve enter the orbit through——- of the skull within the———

two superior orbital fissure common tendinous ring

the——- nerve lies between the two divisions of the occulomotor nerve

nasociliary

The smaller division of the occulomotor nerve runs forwards and—— the optic nerve and supplies the —- rectus, then pierces it to supply the ——-

above superior levator palpebrae superioris.

The larger division passes—— the optic nerve and ——-to supply —— rectus, —- rectus, and —— oblique.

below divides into three branches medial inferior inferior

Trochlear Nerve | -enter the orbit through——and ——- the common tendinous ring

superior orbital fissure superolateral to

Abducent Nerve enter the orbit through —— and—— the common tendinous ring

superior orbital fissure within

——- nerve runs lateral to the 2 divisions of the occulomotor nerve and nasociliary nerve

Abducens nerve

Strabismus/squint: | -occurs when a———. The—— side squints. Causes—— vision because——-

nerve of a voluntary muscle is paralyzed other double light entering the affected eye won’t land on the macula

Paralysis of levator palpebrae superioris: - Paralysis of levator palpebrae superioris due to involvement of the oculomotor nerve leads to —— (aka ——-). - The lesion of——- (as in——) leads to —— as it affects only——- part of LPS.

complete ptosis drooping of upper eyelid cervical sympathetic chain Horner’s syndrome partial ptosis smooth muscle

If suspensory ligament of—— of the eye remains intact when the floor of the orbit is fractured or the maxilla is removed surgically, the eyeball does not sag. T/F

Lockwood T

Enucleation is the surgical procedure that involves removal of the———-, with preservation of——-

entire eye and its intraocular contents all other periorbital and orbital structure

An evisceration of the eye is the removal of the—-, leaving the——-

eye's contents scleral shell and extraocular muscles intact

The central artery of retina - is an example of a ——-artery. - Its damage produces ——-on the ——side of the lesion.

typical end sudden total blindness Same

The ciliary ganglion is blocked to produce—— of pupil before——.

dilatation cataract extraction

Arteries which do not anastomose with their neighbors are called——-

end arteries.

The orbits are seperated from one another by —— sinus and ——- parts of —— cavity

Ethmoidal Upper Nasal

Dimensions of the orbit ``` Volume:—- Horizontal rim:—- Vertical rim—- Intra orbital width—— Extra orbital width—— Medial depth—— Lateral depth—— ```

``` 30ml 40mm 35cm 25mm 100mm 42mm 50mm ```

Medial wall: ——— thick ——- long Majorly formed by lamina ——-

0.2-0.4mm 4.4-5cm Lamina papyracea

Medial to upper part of lacrimal fossa is ——- | Medial to lower part of lacrimal fossa is ———

Anterior Ethmoidal sinus Middle meatus of nose

Just behind the posterior lacrimal crest is the attachment of ——- muscle

Horners

Webers suture???

Infraorbital artery

Since medial wall is the thinnest, ——-is the commonest cause of orbital cellulitis, especially in ———

Ethmoiditis Children

——- wall of orbit is frequently eroded by chronic inflammation lesions, neoplasms, cysts

Medial wall

——- wall of orbit is easily fractured during trauma and during ——- operations

Medial wall | Orbitotomy

Accidental lateral displacement of medial wall can cause ——-

Traumatic hypertelorism

—— wall provides alternative access to the orbit through the ——

Medial Sinus

—— bone can be easily penetrated during eye endoscopy

Lacrimal bone

—— is the shortest orbital wall

The floor

Floor of orbit overlies ——- sinus

Maxillary

Floor of the orbit is bordered laterally by —— fissure and medially by —— suture

Inferior orbital Maxilloethmoidal suture

Flow of the orbit is commonly involved with ——— fractures of the orbit and ——- vessels are always involved

Blow out Infraorbital vessels

——- wall is easily invaded by tumors of the maxillary antrum

Floor

Lateral wall protects —— part of the globe

Posterior part

Palpating—— tumors is easier from the lateral wall than——

Retrobulbar Nasal

Bleeding is least in which wall of the orbit and why

Lateral wall Almost devoid of foramina

——— suture is an important landmark in creating the flap in lateral orbitotomy

Zygomatico-sphenoid suture

The roof of the orbit underlies—— sinus

Frontal

Periorbita peels away easily from —— of the orbit

Roof

—— major blood vessels can be easily nibbed in transorbital orbitotomy

None

At the junction of the roof and medial wall of orbit , the suture line lies in close proximity to ——

Cribiform plate

Any trauma of dura matter and CSF escapes into the ——, ——- or both

Orbit, nose

At junction of late 2/3rd and medial 1/3rd, origin of ——- muscle is prone to fracture and ——-

Inferior oblique muscle Diplopia

Average length of optic canal is —— and connects the orbit to the ——- fossa. Adult dimensions are reached by ——- years

6-11mm Middle cranial 4-5yrs

Superior orbital fissure is a —- shaped aperture and located —- to optic canal

Comma Lateral

Superior orbital fissure is divided into ——,——, and —— by ———

Upper Middle Lower Common tendinous ring

Inferior division of opthalamic vein passes through —- and —— fissure

Superior and inferior orbital fissure

Tolosa hunt syndrome is the inflammation of the ——— and —— of the orbit and can cause a lot of symptoms like ——— and ———- obstruction

Superior orbital fissure Apex Opthalmoplegia Venous outflow

Ophthalmoplegia is the———-.

paralysis or weakness of the eye muscles

Superior orbital syndrome aka—— occurs when there’s a fracture at the fissure and it involves the ——-

Rochon-Duvigneaud Cranial nerves

—— ganglion innervates the eyes

Ciliary

The extraocular muscles are known as the —- muscles

yoke

Levator palpebral has —— and —— parts

Voluntary and involuntary

Involuntary part of the levator palpebral is the ——-

Muller’s muscle

Levator palpebral Origin: Insertion : upper Middle Lower?

Lesser wing of sphenoid Upper lamina- Anterior surface of superior tarsus and skin of upper eyelid Middle-attached to the superior margin of superior tarsus

Eye nerve pathway: contralateral, ipsilateral, bilateral . Central, medial, or lateral subnucleus ``` Levator palpebral Superior rectus Inferior rectus Inferior oblique Medial rectus ```

``` Bilateral;central subnucleus Contralateral medial subnucleus Dorsal ipsilateral;lateral subnucleus Intermediate ipsilateral;lateral subnucleus Central ipsilateral; lates subnucleus ```

Occulomotor nuclei is divided into 2. What are they

Main motor nuclei | Accessory parasympathetic nucleus

The main motor nucleus: - situated at the anterior part of—- matter that surrounds the—- of the—- - at the level of—— colliculus - its out -going fibers pass through the—- and emerge at the anterior surface of the midbrain in——- fossa

grey; periaqueduct; mid brain superior red nuclei interpenduncular

The main occulomotor nucleus gives ——- fibers from both hemispheres ——— fibers from superior colliculus ———- fasciculus connects to CN 4,6,8

Corticonuclear Tectobulbar Medial longitudinal fasciculus

The parasympathetic accessory nuclei of occulomotor nerve : Aka ———- -situated—- to the main occulomotor nucleus -in the orbit , it’s pre ganglionic fibers synapse in the___ -its post ganglionic fibers pass through the short ciliary nerves to the —-and ——of iris -it receives corticonuclear fibers for—— -receives fibers from both—— nuclei for direct and consensual light reflexes

Edinger-westphal nucleus posterior ciliary ganglion ciliary muscles ; constrictor pupillae accommodation reflex pretectal

Course of CN3: - from anterior surface of—- - passes in between the—- and—- arteries - enters the orbit through the—- - divides into superior (——and——), and inferior rami(——,——, and——)

midbrain posterior cerebral; superior cerebellar superior orbital fissure levator palpebral superioris;superior rectus inferior rectus; middle rectus; inferior oblique

Complete lesion of the occulomotor nerve can be caused by: - diabetes - tumors - aneurysm - vascular disease in the midbrain like —— syndrome and ——- syndrome

Benedikt | Weber

``` Complete lesion of the occulomotor nerve can cause -external—— ——- ——- ——-of pupil and—- to light -accommodation of eye is paralyzed ```

strabismus ptosis diplopia wide dilation; unresponsive

External strabismus is the eye looking —— at rest and occurs due to ——-

Laterally Lateral rectus

Diplopia means ——-

Double vision

Wide dilatation of eye and unreactive to light is due to paralysis of ———-

Sphincter pupillae

Incomplete lesion of occulomotor nerve can cause internal or external ———-

Opthalmoplegia

In Internal Opthalmoplegia,there is -normal INNERVATION of ———but selective loss of autonomic INNERVATION of the——- While in external Opthalmoplegia ,there is -normal INNERVATION of—— and —— is paralyzed

extraocular muscles sphincter pupillae and ciliary muscle sphincter pupillae and ciliary muscle Extraocular muscles

Cornea is capable of regeneration | T/F

Infants orbit look more laterally than adult orbits | T/F

Orbital index is higher in a child when compared to adults | T/F

Visual pathway forms a binocular representation on one distinct object T/F

F It’s monocular

ORBIT Flashcards

(142 cards)