Anatomy: Eye

Front 1

What bone is broken in a blowout fracture? What structure can get caught in the fracture?

Back 1

The maxillary bone is broken and can catch the inferior rectus muscle of the eye.

Front 2

What makes up the outer layer of the eye?

Back 2

Sclera
Cornea

Front 3

What makes up the middle layer of the eye?

Back 3

Choroid
Ciliary body
Iris

Front 4

What makes up the inner layer of the eye?

Back 4

Retina

Front 5

What structure separates the anterior and posterior chambers of the eye?

Back 5

Iris

Front 6

What structure suspends the lens in the eye?

Back 6

Zonular fibers

Front 7

What supplies the most acute vision?

Back 7

Macula with fovea centralis

Front 8

What causes the blind spot?

Back 8

Optic disc: entry of the optic nerve with central retinal vessels

Front 9

What kind of innervation does the ciliary body receiver?

Back 9

Only parasympathetics

Front 10

Describe Schlemm's canal.

Back 10

Allows the flow of aqueous humor from the ciliary process to the scleral venous sinus.

Front 11

What is glaucoma?

Back 11

intraocular pressure greater than 20-22 mmHg

Front 12

The anterior and posterior chamber can communicate via what structure?

Back 12

Schlemm's canal

Front 13

Blockage of what artery will result in immediate irreversible blindness?

Back 13

Central artery

Front 14

What are the two artery branches that feed the eye?

Back 14

Posterior ciliary arteries and Central artery (both off of the ophthalmic)

Front 15

The central artery is a branch of the artery?

Back 15

The ophthalmic

Front 16

Describe the light reflex.

Back 16

In:II
Out: III and sympathetic (to dilate)

Front 17

Describe the visual blink reflex.

Back 17

In: II
Out: VII

Front 18

Describe the accommodation reflex.

Back 18

In: II
Out: III

Front 19

What nerve supplies general sensory to the cornea?

Back 19

V1

Front 20

Describe the corneal reflex.

Back 20

In: V1
Out: VII

Front 21

Describe the path of light sensory input from the eye to the brain.

Back 21

Retina to optic nerve to optic chiasm to optic tract.

Front 22

Is it better to lose a optic nerve or optic tract?

Back 22

Optic nerve: like losing one eye. Where optic tract lesion would lose half visual field from both eyes.

Front 23

What does the levator palpebrae do?

Back 23

Elevates the upper eye lid

Front 24

What nerve innervates the levator palpebrae?

Back 24

CN III

Front 25

What is the action of the superior tarsal muscle?

Back 25

Elevate of the upper eyelid.

Front 26

What innervates the superior tarsal muscle?

Back 26

SNS

Front 27

What is the insertion for the superior tarsal and levator palpebrae?

Back 27

Superior tarsal plate

Front 28

What membrane encapsulates the eye and separates it from the orbital fat?

Back 28

Bulbar sheath

Front 29

What cavities are continuous with the bulbar sheath?

Back 29

Subdural and subarachnoid cavities

Front 30

Palsies of which nerves can cause ptosis?

Back 30

CN III
Cervical plexus

Front 31

What is the tendinous ring at the apex of the orbit?

Back 31

Annulus Tendineus

Front 32

What are the muscles of the Annulus Tendineus?

Back 32

Rectus muscles
Superior
Medial
Inferior
Lateral

Front 33

What nerves gain the orbit via the superior orbit fissure (7)?

Back 33

Frontal nerve (CN V1)
Lacrimal nerve (CN V1)
Trochlear nerve (CN IV)
Oculomotor x2 (upper and lower) (CN III)
Abducens (CN VI)
Nasociliary (CN V1)

Front 34

What structures gain the orbit via the optic canal?

Back 34

CN II
Ophthalmic artery

Front 35

What extraocular muscles do not originate from the annulus tendineus?

Back 35

Superior oblique
Inferior oblique

Front 36

The outer sheath of the optic nerve is a continuation of what membrane?

Back 36

Meningeal dura

Front 37

What would the pupil look like is patient with an SNS block?

Back 37

Pin pointed pupils

Front 38

You want to isolate the abducens nerve in the left eye. Explain what direction you would have the patient look.

Back 38

Outward (to the left)

Front 39

A patient with Horner's syndrome will have pupils that are...

Back 39

Constricted

Front 40

You want to isolate the trochlear nerve in the left eye. Explain what direction you would have the patient look.

Back 40

Inward towards the nose and downward

Front 41

To direct the gaze downward, what muscles and nerves are involved?

Back 41

Inferior rectus (CN III)
Superior oblique (CN IV)

Front 42

An infection that spreads from the face to the cavernous sinus must travel on what vessels?

Back 42

The ophthalmic veins are continuous with the facial vein and the pterygoid plexus of veins.
These veins drain the face toward the cavernous sinus. They are valveless, so infections from the face can drain into the cavernous sinus.

Front 43

An infection in the cavernous sinus may compress what nerves?

Back 43

Headed to superior orbital fissure:
CN III
CN IV
CN V1
CN VI

CN V2: headed for rotundum

Front 44

Which muscles of the eye are involved in adduction?

Back 44

medial rectus
superior rectus
inferior rectus

Front 45

Which muscles of the eye are involved in abduction?

Back 45

lateral rectus
superior oblique
inferior oblique

Front 46

Which muscles of the eye are involved in elevation?

Back 46

superior rectus
inferior oblique

Front 47

Which muscles of the eye are involved in depression?

Back 47

inferior rectus
superior oblique

Front 48

Which muscles of the eye are involved in medial rotation?

Back 48

superior oblique
superior rectus

Front 49

Which muscles of the eye are involved in lateral rotation?

Back 49

inferior rectus
inferior oblique

Front 50

Since both superior rectus and inferior oblique can elevate the eye, how can you isolate each?

Back 50

Adduction and elevation = inferior oblique

Abduction and elevation = superior rectus

Front 51

What are the three main branches of the frontal nerve?

Back 51

Supratrochlear
Supraorbital
Nasociliary

Front 52

What are the two main branches of V1?

Back 52

Lacrimal
Frontal

Front 53

How does contraction and relaxation of the ciliary muscles affect the shape of the lens?

Back 53

Contraction: round (fat)
Relaxation: Flat

Front 54

How do sympathetics reach the dilator pupillae?

Back 54

SCG to the sympathetic root to the ciliary ganglion to the long and short ciliary nerve to the DP

Front 55

How do sympathetics reach the superior tarsal muscle?

Back 55

on CN III

Front 56

How do the parasympathetics reach the ciliary body and sphincter pupilae?

Back 56

On lower branch of CN III to the ciliary ganglion to the short ciliary nerves to the CB and SP.

Front 57

What do parasympathetics to the ciliary body do?

Back 57

thicken the lens (contract the muscle) for accommodation to near vision.

Front 58

What do parasympathetics to the sphincter pupillae do?

Back 58

Contract the muscle to constrict the pupil in response to light

Front 59

What are the parasympathetic reflexes of the eye? What CN is involved?

Back 59

Light reflex: constriction of the pupil
Accommodation: constriction of the ciliary body
CN III

Front 60

How can you test between the muscles that can depress the eye?

Back 60

Abduct and depress: IR
Adduct and depress: SO

Front 61

Where does the nerve to the lacrimal gland synapse?

Back 61

pterygopalatine ganglion

Front 62

Where does the blood from the eye drain?

Back 62

Pterygoid plexus and cavernous sinus