Cranial Nerves And Of The Eye And Orbit

Question 1

What are the CN that innervate the eye and ocular structures?

Answer 1

CNII: optic 
CNIII: oculomotor 
CNIV: trochlear 
CNV: trigeminal: ophthalmic 
CN V: trigeminal: max
CNVI: abducens
CNVII: facial

Question 2

Afferent pathway

Answer 2

Orbital sensory innervation

Away from target organ

Question 3

Sensations that affect eye

Answer 3

Pain, touch, reassure, warmth, cold,

Question 4

Sensations from the cornea, iris, conj, and sclera consist of primarily ____

Answer 4

Pain

Question 5

Light touch of the cornea

Answer 5

Registered as irritation or pain

Question 6

The fibers of the trigeminal nerve serving the ocular structures are _____ and originate in the innervated structures

Answer 6

Sensory

Question 7

What is the first branch of the trigeminal nerve

Answer 7

Ophthalmic branch

Question 8

What is the first branch of the ophthalmic nerve

Answer 8

Nasociliary N

Question 9

Sensory fibers form the structures of the medial canthal area-caruncle, canaliculi, lacrimal sac, medial aspect of the eyelids, and skin at the side of the nose-join to form

Answer 9

Infratrochlear nerve

Question 10

The infratrochlear nerve penetrates the orbital septum and enters the orbit where

Answer 10

Below the trochlea

Question 11

Where does the infratrochlear nerve run before it joins the next branch

Answer 11

Along the upper border of the medial rectus muscle

Question 12

Where does the infratrochlear nerve become the nasociliary nerve?

Answer 12

As it runs across the upper border of the medial rectus muscle and other branches join it

Question 13

Sensory fibers from the skin along the center of the nose, the nasal mucosa, and the ethmoid sinuses form the _______

Answer 13

Anterior ethmoid nerve

Question 14

Fibers from the ethmoid sinuses and the sphenoid sinus form the _____

Answer 14

Posterior ethmoid nerve

Question 15

Where do the ethmoid N enter the orbit and with what

Answer 15

With their companion arteries through the foramina within the frontoethmoid suture

Question 16

Both ethmoid nerves join the _____ as it runs along the medial aspect of the orbit

Answer 16

Nasociliary nerve

Question 17

Corneal sensory innervation is estimated to be _____ times as dense as other epithelial tissue innervation

Answer 17

4oo times

Question 18

Where is the corneas sensory innervation?

Answer 18

In the epithelium, anterior stroma, and mid stroma. None in posterior stroma, Decemets membrane or endothelium

Question 19

How do the long ciliary nerves course?

Answer 19

Between the choroid and sclera to the back of the eye where they leave the globe at points appx 3mm on each side of the optic nerve

Question 20

What makes up the nasociliary nerve

Answer 20

• Infratrochelar
• Anterior and posterior ethmoid
• long ciliary nerve

Question 21

How do the short ciliary nerves run to the back of the eye where they emerge?

Answer 21

From limbus of cornea, join other sensory nerves from ant set, enter choroid, join choroidal nerves, course to back of eye, leave as 6-10 short ciliary nerves

Question 22

Where do the short ciliary nerves exit the sclera

Answer 22

In a ring around the optic nerve in company with the short post ciliary arteries.

Question 23

After the short ciliary nerve leaves the back of the eye, what is the next structure that it PASSES THROUGH?

Answer 23

Ciliary ganglion, does not synapse here!

Question 24

After the short ciliary nerves leave the ciliary ganglion, what do they join

Answer 24

Nasociliary nerves

Question 25

What kind of fibers does the short ciliary nerve carry?

Answer 25

Symp and parasympathetic in addition to sensory

Question 26

Structures that exit the posterior of the eyeball

Answer 26

- vortex veins (4) - long ciliary arteries (2) - long ciliary nerves (2) - short ciliary arteries (many) - short ciliary nerves (many)

Question 27

The nasociliary nerve is formed by the joining of..

Answer 27

- infratrochlear nerve - anterior and posterior ethmoid nerves - long ciliary nerves - sensory root of ciliary ganglion

Question 28

How does the nasociliary nerve exit the orbit?

Answer 28

Passing through the oculomotor foramen WITHIN the common tendinous ring, and the superior orbital fissure into the cranial cavity

Question 29

Does the nasociliary nerve run inside or outside the common tendinous ring?

Answer 29

Inside

Question 30

____ of all cases of herpes zoster (shingles) will affect the ophthalmic division of trigeminal.

Answer 30

10%

Question 31

What indicates that the nasociliary nerve has been affected by herpes zoster via the infratrochlear nerve?

Answer 31

Rash on the side or tip of the nose

Question 32

Why is the cornea almost always affected in herpes zoster that presents with rash on side or tip of nose?

Answer 32

Nasociliary nerve is affected via the infratrochlear nerve, thus the corneal will effected by way of the short/long ciliary nerves coming off of the nasociliary

Question 33

What is the rash on the side/tip of nose called in herpes zoster (shingles)

Answer 33

Hutchinsons sign

Question 34

Sensory fibers from the skin and muscles of the forehead and upper eyelid come together and form the

Answer 34

Supratrochlear nerve

Question 35

How does the supratrochlear nerve enter the orbit

Answer 35

By piercing the superior medial corner of the orbital septum

Question 36

Sensory fibers from the skin and muscles of the forehead and upper eyelid form a second nerve called the

Answer 36

Supraorbital nerve

Question 37

How is the supraorbital nerve in relation to the supratrochlear nerve

Answer 37

Lateral

Question 38

How does the supraorbital nerve enter the orbit

Answer 38

As one or two branches | -one branch enters through the supraorbital notch, accompanying the supraorbital artery

Question 39

Where does the supraorbital nerve join the supratrochlear nerve and what does it form at that point?

Answer 39

Midway in the orbit , forms frontal nerve

Question 40

How does the frontal nerve course?

Answer 40

Back through the orbit between the levator muscle and the periorbita

Question 41

How does the frontal nerve exit the orbit

Answer 41

Through the superior orbital fissure above the common tendinous ring

Question 42

Is the frontal nerve inside or outside the common tendinous ring?

Answer 42

Outside

Question 43

What is the 3rd branch of the ophthlamic division of trigeminal

Answer 43

Lacrimal nerve

Question 44

Sensory fibers from lateral aspect of the upper eyelid and temple area come together and enter the lacrimal gland. They join the sensory fibers hat serve the gland itself to form the

Answer 44

Lacrimal nerve

Question 45

How does the lacrimal nerve leave the gland and run in the orbit?

Answer 45

Runs posteriorly along the upper border of the lateral rectus muscle where it receives a branch from the zygomatic nerve containing autonomic innervation from the lacrimal gland

Question 46

Where does the lacrimal nerve exit the orbit?

Answer 46

Through the superior orbital fissure above the muscle cone

Question 47

What is the most important sensory nerve of the orbit?

Answer 47

Ophthalmic nerve

Question 48

After exiting the orbit, the nasociliary nerve, lacrimal nerve, and frontal nerve join and form the

Answer 48

Ophthalmic division of the trigeminal nerve

Question 49

After all of the nerves come together to form the ophthlamic nerve, where does it go?

Answer 49

Enters the lateral wall of the cavernous sinus where it receives sensory fibers from the oculomotor, trochlear, and abducens

Question 50

The infraorbital nerve, formed by the sensory fibers from the cheek, upper, and lower eyelid enters the maxillary bone though the

Answer 50

Infraorbital foramen

Question 51

How does the infraorbital nerve run through the maxillary bone?

Answer 51

It runs posteriorly through the infraorbital canal and groove; while it is isn the maxillary bone, branches join it from the upper teeth and maxillary sinus

Question 52

As the infraorbital nerve leaves the infraorbital groove it exits the orbit through the _____________

Answer 52

Inferior orbital fissure

Question 53

After the infraorbital nerve passes through the inferior orbital fissure what happens

Answer 53

Joins other fibers in forming the maxillary nerve

Question 54

Sensory fibers from the lateral aspect of the forehead enter the orbit through a foramen in the zygomatic bone as the ____________

Answer 54

Zygomaticotemporal nerve

Question 55

Fibers from the lateral aspect of the cheeks and lower eyelid enter the orbit through a Forman in the zygomatic bone as the __________

Answer 55

Zygomaticofacial nerve

Question 56

What do the zygomaticotemporal and zygomaticofacial nerve join to become?

Answer 56

Zygomatic nerve

Question 57

How does the zygomatic nerve course?

Answer 57

Courses along the lateral orbital wall

Question 58

How does the zygomatic nerve exit the orbit?

Answer 58

Through the inferior orbital fissure and joint with the maxillary nerve

Question 59

The maxillary nerve traverses the area between the __________

Answer 59

Maxilla and the sphenoid bone

Question 60

As the maxillary nerve passes near the pterygopalatine fossa, it receives ____

Answer 60

Some autonomic fibers from the pterygopalatine fibers from the pterygopalatine ganglion

Question 61

Where are the autonomic fibers from the pterygopalatine fossa that run through the maxillary nerve destined?

Answer 61

Lacrimal gland

Question 62

How does the maximally nerve enter the skull

Answer 62

Through the foramen rotundum

Question 63

What is the most superior nerve in the cavernous sinus

Answer 63

Oculomotor

Question 64

What is the most inferior nerve in the cavernous sinus

Answer 64

Maxillary

Question 65

What is the most medial nerve in the cavernous sinus

Answer 65

Abducens

Question 66

Order of the CN from superior to inferior in the cavernous sinus

Answer 66

``` Oculomotor Trochlear Abducens (medial) Ophthalmic Maxillary ```

Question 67

What artery runs through the cavernous sinus

Answer 67

Internal carotid

Question 68

Cranial nerves that supply striated muscles of the orbit and adnexa

Answer 68

Oculomotor Trochlear Abducens Facial

Question 69

How does the oculomotor nerve run in the cavernous sinus

Answer 69

Pierces the roof of the cavernous sinus and runs within the two dural layers of the its lateral wall above the trochlear nerve

Question 70

While in the cavernous sinus, the oculomotor nerve sends __________ to the ophthalmic nerve

Answer 70

Small sensory branches

Question 71

Where does the oculomotor nerve enter the orbit?

Answer 71

Through the superior orbital fissure, having divided into superior and inferior divisions

Question 72

Where are both divisions of the oculomotor nerve located

Answer 72

Within the oculomotor foramen

Question 73

How does the superior oculomotor branch run

Answer 73

Medically above the optic nerve

Question 74

After coursing with the optic nerve, how does the superior division of oculomotor go?

Answer 74

Enters the superior rectus on its inferior surface

Question 75

How does the superior oculomotor branch innervate the levator palpebrae superioris through the superior rectus?

Answer 75

Additional fibers either pierce the muscle or pass around its border to innervate the levator palpebrae superioris

Question 76

How does the inferior branch of he oculomotor run in relationship to optic nerve

Answer 76

Runs below the optic nerve and divides into three branches

Question 77

What does the first branch of the inferior oculomotor nerve do

Answer 77

Enters the medial rectus on its lateral side

Question 78

What does the second branch of the inferior oculomotor nerve do

Answer 78

Enters the inferior rectus on its upper surface

Question 79

What does the theirs branch of the inferior oculomotor nerve

Answer 79

Gives off parasympathetic fibers that form the parasympathetic root extending to the ciliary ganglion

Question 80

How does the inferior oculomotor branch run after it gives off its three branches?

Answer 80

Runs along the lateral border of the inferior rectus, crossing it to enter the inferior oblique muscle near its midpoint

Question 81

What kind of innervation is trochelar

Answer 81

Motor only

Question 82

What does the trochlear nerve innervate?

Answer 82

Superior oblique muscle

Question 83

The trochlear nerve and hte cavernous sinus

Answer 83

Enters the wall of the cavernous sinus and lies abtween the oculomotor nerve and the ophthalmic division of the trigeminal nerve

Question 84

While in the cavernous sinus, what does the trochlear nerve do

Answer 84

Sends sensory fibers to the ophthalmic nerve

Question 85

How does the trochelar nerve enter the orbit

Answer 85

Through the superior orbital fissure above the common tendinous ring OUTSIDE the muscle cone

Question 86

How does the trochlear muscle run

Answer 86

With the frontal nerve to the medial side of the orbit above the levator and superior rectus muscles and enters the upper surface of the superior oblique muscle

Question 87

Within the cavernous sinus, the abducens lies near the _____

Answer 87

Lateral wall of the internal carotid artery

Question 88

How does the abducens nerve enter the orbit?

Answer 88

Through the superior orbital fissure WITHIN the common tendinous ring

Question 89

What does the abducens nerve innervate

Answer 89

The lateral rectus muscle on the medial side

Question 90

This gives motor supply to the frontalis, procerus, corregator, and orbicularis oculi muscles

Answer 90

The temporal and zygomatic branches of the facial nerve (upper two)

Question 91

What are the roots of the facial nerve?

Answer 91

Large motor root that innervates the facial muscles and the smaller root contains sensory and parasympathetic fibers

Question 92

What do the sensory fibers of the smaller root of the facial root carry?

Answer 92

Taste sensations from tongue

Question 93

What do the parasympathetic fibers from the smaller root of the facial nerve do

Answer 93

Supple secretomotor fibers to various glands of the face including the lacrimal glands