Orbit, Cn 7, And Ear

Front 1

Which 3 bones form the front of the orbit?

How far back in the orbit do they go?

Back 1

frontal, zygoma, and maxilla

a decent ways back (like half)

Front 2

What are the two holes above and below the orbit? What does through them?

Back 2

Supra and Infra- orbital foramen

they give out the opthalmis and maxillary divisions of the trigeminal nerve respectively

Front 3

What other hole is lined up in the same saggital place as the infra and supra orbital foramen?

Back 3

the mental foramen (for the mandibular division of CN )

Front 4

Label these (include lines)

Back 4

Lacrimal
Ethmoid
Sphenoid

Front 5

Which of those previous bones are prone to blowout fractures? Why?

Back 5

the lacrimal and ethmoid bones because they are paper thing and can break easily during traume

Front 6

What do the medial and lateral walls of the orbit look like? (what angles are they at relative to one another?

Back 6

Front 7

What implication does the axis of the orbit not lining up with the axxis of the eyeball have?

Back 7

the muscles and nerves that come out of there will have to attach obliquely

Front 8

What are the 3 layers of the eyeball?

Back 8

1. Sclera
2. Choroid
3. Retina

Front 9

What type of tissue is the sclera made of? Why is this functionally important?

Back 9

collagen so it can seamlessly integrate with tendons of all the occular muscles

(this is also why the eyeball is white)

Front 10

What is contained in the choroid?

What does choroid generally refer to?

Back 10

all the vessels and nerves that aren't the optic nerve

choroid generally containing many blood vessels

Front 11

What is contained in the retina?

Back 11

all the neural stuff. light and mechanical receptors and their connections.

Front 12

What provides the sensory innervation of the eye?

Back 12

CN V1

Front 13

What travels in the optic canal with the optic nerve?

Back 13

the opthalmic artery

Front 14

What major artery does the opthalmic artery come off of and does it only supply the eye?

Back 14

the internal carotid and no it supplies a lot of the face

Front 15

What is in the superior orbital fissure vs inferior orbital fissure? Which is more important?

Back 15

superior- (more superior haha) has all of the other neurons and the superior opthalmic vein

inferior- only the inferior opthalmic vein

Front 16

What is the path of tears in the eye?

Back 16

lacrimal gland in upper lateral orbit (not shown) secretes them and this washes accross to the nasolacrimal canal to be drained

Front 17

What is the common tendonous ring? Where is it very functionally placed.

Back 17

a tendonous ring attachment for all eye muscles. it is placed over the superior orbital fissure where all the motor nerves come out!

Front 18

What is the only muscle not attached to the tendonous ring?

Back 18

the inferior oblque

Front 19

Name these muscles

Back 19

Front 20

Which muscles does CN 3 innervate? How many divisions in the superior fissure does it have?

Back 20

superior, inferior, and me dial rectus
and Levator palpebrae superioris

this is the levatator palpebrae superioris

Front 21

What nerves that aren't involved in the orbit come out of the superior orbital fissure?

Back 21

the sensory branches of CN5 for the top of the face

Front 22

Name these actions

Back 22

Front 23

What is the main point of rotating your eyes? (besides being exasperated)

Back 23

to maintain eye position while turning your head

Front 24

ither terms for internal and internal rotation?

Back 24

intorsion and extorsion

Front 25

What part of the eyeball so the rectus vs oblique muscle attach?

Back 25

rectus- anterior
oblique- posterior

Front 26

Show how the superior oblique runs.

Also compare this to the inferior oblique

Back 26

1. parralell to the medial rectus
2. threaded through troclea
3. attached to back of eye past the superior rectus

Inferior oblique- the same medial course except it attaches underneath the eye

Front 27

Show a posterior view of the muscles

Back 27

Front 28

What is functionally significant about the obliques attching to the back of the eye?

Back 28

they will move the eyeball to the opposite side of their pull

(imagine if back of eyeball was the front)

Front 29

Does the action of the obliques stay constant?

Back 29

no they change with position of the ye

Front 30

what is their role when the eye in straight?

Back 30

superior- intorsion
inferior- extorsion

Front 31

What is their role when the eye is adducted?

Back 31

superior- depression
inferior- elevation

Front 32

So why would a lesion of CN 3 cause you to be down and out? (lateral strabismus)

Back 32

because then the actions of the SO and LR are unopposed.

laterall will pull to the side
SO will depress and internally rotate

Front 33

What part of the eye are we referring to when we talk about internal and externalroation?

Back 33

the top of the eyes

Front 34

The occular muscles all have secondary actions moving the eye as long as they are not along the same action of rotation.

Back 34

let's talk about this

Front 35

Do either of the obliques have medial adduction power?

Back 35

no

Front 36

Do they have lateral abducion power?

Back 36

yes, weakly

Front 37

What phenomenon does this explain?

Back 37

why lazy eyes are usually to the side

Front 38

Which actions are controlled completely by CN IIi with nothing else being able to compensate?

Back 38

adduction, elevation, and extorsion

Front 39

Which two muscles control the eyelid opening?

Show

Back 39

superior tarsal and Levatato papebrae superioris

Front 40

What kind of muscle is each and what nerve innervates them?

Back 40

superior tarsal- SM controlled by sympathetics
levatator palepebrae superioris- skeletal muscle controlled by CN 3

Front 41

This is what you will see when you remove the frontal bone.

What surrounds this that is not shown?

Back 41

a bunch of fat to pad the eye

Front 42

there are nerves that go into the eyeball? What do they do?

Back 42

smooth muscle control in the eyeball or sensory info for CN 5

Front 43

How does CN 3 split up? Which muscles does each division innervate?

Back 43

splits into inferior and superior at the tendonous ring
superior- levator papebrae superioris and superior rectus (look up and rise lids)
inferior- everything else

Front 44

Describe the blue lines here.

Back 44

the are the S and PS innervations.

PS- have to stop at ciliary ganglion first
S- are post ganglionic and split into 2 branches. One for the pupil dilator via the ring and the other for the superior tarsal.

Front 45

How do the CN 4 and 6 travel?

Back 45

pretty straighforward except that 4 crosses behind the midbrain.

They both come out through the superior orbital fissure and innervate their one muscle.

Front 46

How do the pupil smooth muscles get their innervation? (what layer of the eyeball do the nerves travel in?)

Back 46

the choroid layer

Front 47

describe how the pre and post sympathetic fibers travel to the eye.

Back 47

1. come out of T1
2. travel through the sympathetic trunk to synapse of the superior cervical ganglia
3. travel up the carotid plexus (around external carotid artery) to the eyeball
4. they have to travel through the ciliary ganglion, but they don't synapse there

Front 48

Imagine the territories of the 3 division of the trigeminal

Back 48

they all come down from a common point in the lateral head bone (lolw/e)

they end before the ear
mouth is boundary between maxillary and mandibular.
opthalmic and maxillary meet at the tip of the nose

Front 49

Where does the trigeminal ganglion sit in the skull and which foramen do it's 3 divisions go through?

Back 49

in the middle cranial fossa
V1- superior orbital fissure
V2- Foramen Rotundum
V3- Foramen Ovale

Front 50

What is the cowboy ross mnemonic?

Back 50

cowboy ROS sits on the sella tucica saddle

His eyes- look through the optic canal
His legs- he laces up his boots and puts them through the foramen lacerum (L for legs)
Between this, there are 3 holes that spell his name from rostral to caudal
Rotundum
Ovale
Spinosum
Horse- he rides on his horse CLIVUS who hold two JUGs of water
Crib- He is going to to his CRIB(iform plates) where he is going to get some crystal (CRISTA GALLI)

Front 51

Show and tell where he puts his hand and leans back on.

Back 51

holds onto two anterior clinoid processes
leans back on posterior clinoid processes

Front 52

Where is the superior orbital fissure in all this?

Back 52

underneath the optic canal and the anterior clinoid process

Front 53

What is the mnemonics for what the 3 different CN5 divisions supply? (don;t give what they stand for yet)

Back 53

1. Opthalmic- NFL (watch NFL)
2. Maxillary- ZIP (maxillary zips the other two together)
3. Mandibular- BAIL (use your mouth to bail you out of jail)

Front 54

What does V1 NFL stand for?

Back 54

Nasalciliary
Frontal
Lacrimal

Front 55

What does V2 ZIP stand for?

Back 55

Zygoma
Infraorbital
Pterygopalatine

Front 56

What does V3 BAIL stand for?

Back 56

Bucchal
Auricotemporal
Inferior Alveolar
Lingulal

Front 57

Which is the only nerve that innervates the eyeball?

Back 57

Nasociliary

Front 58

What is pretty awesome about the location of the parasympathetic ganglia (4) in the face?

Back 58

they are right along the rooute of the sensory nerve of it's reflex arc

Front 59

Show where the opthalmis artery travels.

Back 59

in the optic canal

Front 60

What would happen if you had an occlusion of the opthalmic artery? WhY?

Back 60

complete blindness in that eye since this is the only artery that supplie the retina

Front 61

Show how the dura line the eye (and the orbital fat)

what is the orbital fat analogous to in the spine?

Back 61

periosteal dura lines the pyrimid that is the orbit of the eye while the meningeal dural travels along with it on the sclera.

Fat fills in space between the dura the same as epidural fat in the spinal column

Front 62

Where do the ophthalmic veins come from and drain toward?

What is a risky feature they share with the spinal veins?

Back 62

they come from the superior and inferior orbital fissures

they drain toward the nose outside the eye.

they don't have valves so infection can spread

Front 63

What does the superior opthalmic vein also drain?

Why do we care about this small sinus?

Back 63

the cavernous sinus

a lot of sensitive stuff is there. (All the eye cranial nerves, V1 and 2, pituitary gland, and internal carotid artery)

Front 64

Which nerve would be affected first in a thrombolytic cavernous sinus lesion? WHy?

Back 64

CN 6 becasue it is right in the middle next to the internal carotid whereas the other are on the side

Front 65

NOW WE TALK ABOUT THE EAR

Back 65

YAY

Front 66

Imagine what the external, middle, and internal ear look like

Back 66

Front 67

What are the meatuses made of and filled with?

Back 67

they are are air-filled cartilaginous tubes.

Front 68

Where does the internal acoustic meatus exit into the skull?

Back 68

the posterior cranial fossa

Front 69

What goes through the internal auditory meatus?

Back 69

CN 8

Front 70

What are the 3 ear bones connected by?

Back 70

synovial joints

Front 71

Mnemonic for order of the 3 bones?

Back 71

MISO soup!

From TM:
Malleolus
Incus
Stapes
Oval Window

Front 72

How does the middle ear concentrate sound?

Back 72

the attachment of the mallelus to the TM is larger than the stapes to the oval window, making the pressure bigger

PHYSICS!

Front 73

What is conductive hearing loss?

Back 73

a problem with the conduction system in the external or middle ear

Front 74

What do the 3 bones look like? Menmonic.

Back 74

a shoulder- malleus
bent arm- incus
shovel hand- stapes

Front 75

What is there is a problem in the cochlea? WHat is it called?

Back 75

sensory hearing loss.

Front 76

What are the two smooth muscles of the ear? What do they attach to?

Back 76

tensor tympani attaches to maaleus
stapedius attached to (surprise) stapes

Front 77

function of the tensor tympani?

Back 77

limit movement of the malleus to dampen the sound of our own voice. (it is attached to vibrations in our skull)

Front 78

function of the stapedius?

Back 78

contracts reflexively to loud sounds to disarticulate the stapes from the incus to dull transmission.

Front 79

What CN control which SM?

Back 79

CN 5- tensor tympani
CN 7- Stapedius

Front 80

What auditory sx would we get with a CN 5 lesion?

Back 80

our own voice may sound louder, but nothing significant

Front 81

What auditory sx would we get with a CN 7 lesion?

Back 81

we wouldn't be able to damped loud sounds and we would get HYPERACUSIS (startled by loud sounds)

Front 82

What is the chorda tympani?

Back 82

mixed branch of CN 7 along the TM. Just passing through!

Front 83

View from TM

What give sensation to the middle ear mucosa?

Back 83

CN 9

Front 84

Where does CN 7 come through the skull?

Back 84

stylomastoid foramen

(between spikey styloid process and mastoid bone)

Front 85

Who do I know who had this nerve nicked?

Show pic of location.

Back 85

that girl, Ana Maria. She had a surgert that nicked here.

Front 86

Which parts of CN 7 come through this foramen?

Back 86

all the skeletal muscles it innervates

but not the stapedius

Front 87

Mnemonic for the 5 MUSCULAR branches of the facial nerve?

Back 87

TWO- temporal
ZEBRAS- zygomatic
BIT- buccal
MY- marginal mandibular
COOKIE- cervical

Front 88

Narrate this.

Back 88

CN 7 has 2 major routes of mixed fibers.
Muscles, salivary glands, and taste go through the lower route. They drop off the stapezius branch as they pass the middle ear.
Nasal and oral mucosal secretion and taste go throught the upper branch
They lower branch goes through the stylomastoid foramen and joins with the superior division at the genticulate ganglion.
They both happily go through the internal auditory meatus into the brainstem

Front 89

Why was that necessary to know?

Back 89

you can determine where the lesion on CN 7 is basen on sx

Front 90

What if you only had the facial muscles paralyzed and nothing else? Where is the lesion?

Back 90

at the lower branch of the facial nerve

Front 91

What if you lost all taste?

Back 91

the it would have to be somewhere before the genticulate ganglion.

Front 92

What is a secondary function of the nerves of CN 5?

Back 92

other nerves send fibers there to hitchhike to their destination

Front 93

Where is the internal auditory meatus inside the skull? Menmonic?

Back 93

in the posterior cranial fossa anterior to the jugular foramen.

The horse (clivus) needs to listen for danger.

Front 94

Mnemonic for what the middle/outer ear resembles

Back 94

a snail getting suckerpunched

Front 95

In the brainstem, what CN does CN 7 follow out closely? Why?

Back 95

CN 8 because it wants to go to the middle ear to drop off it's stapedius connection before going on to do everything else

Front 96

Where would the lesion/infection be if you had left facial paralysis AND hyperacusis?

Back 96

before the genticulate genu (bend of CN 7) and the part where CN 7 goes through the middle ear.