Eye

Question 1

What 7 bones make up the bony orbit?

Answer 1

1. frontal
2. sphenoid (lesser and greater wings)
3. ethmoid
4. lacrimal
5. maxillary
6. zygomatic
7. palatine

Question 2

What are the 9 apertures of the bony orbit?

Answer 2

Near apex - 3:
optic canal
superior orbital fissure
inferior orbital fissure

Near base - 3:
rim of the bony orbit
fossa of lacrimal duct
superior orbital foramen

On medial and inferior walls - 3:
infraorbital groove
infraorbital foramen
ant./post. ethmoidal foramina

Question 3

What passes through the optic canal?

Answer 3

1. CN II

2. ophthalmic artery

Question 4

What passes through the superior orbital fissure?

Answer 4

1. CN III, IV, ophthalmic branch of V, VI

2. superior ophthalmic vein

Question 5

What passes through the inferior orbital fissure?

Answer 5

infraorbital nerve of V2

Question 6

What transmits the infratrochlear nerve?

Answer 6

rim of bony orbit

Question 7

What is in the fossa of the lacrimal duct?

Answer 7

lacrimal lake
lacrimal papillae
lacrimal sac
nasolacrimal duct

Question 8

What passes through the supraorbital foramen?

Answer 8

supraorbital nerve (terminal branch of frontal nerve of V1), artery, and vein

Question 9

What passes through the infraorbital foramen?

Answer 9

infraorbital nerve (branch of V2), artery, and vein

Question 10

What passes through the anterior and posterior ethmoidal foramina?

Answer 10

nerves and vessels of the same name

Question 11

Where are the tarsal plates?

Answer 11

embedded in each eyelid

Question 12

What attaches to the tarsal plate?

Answer 12

levator palpebrae superioris

Question 13

Describe the path of a tear.

Answer 13

lacrimal gland
across the globe
collect in lake
drain into punctum
through lacrimal canaliculus
into lacrimal sac
through nasolacrimal duct
out into nasal cavity

Question 14

What are the 3 muscles that move the eyelids?

Answer 14

1. orbicularis oculi - orbital part (wink)
2. orbicularis oculi - palpebral part (blink)
3. levator palpebrae superioris (open)

Question 15

What innervates orbicularis oculi?

Answer 15

CN VII

Question 16

What innervates levator palpebrae superioris?

Answer 16

superior division of CN III

Question 17

What is the function and innervation of the superior tarsal muscle (of Muller)?

Answer 17

smooth muscle arising from levator palpebrae superioris; opens eyes when startled; sympathetic fibers from carotid plexus

Question 18

What are the 6 extraocular muscles?

Answer 18

4 rectus:
superior rectus
medial rectus
inferior rectus
lateral rectus

2 oblique:
superior oblique
inferior oblique

Question 19

Which extraocular muscles adduct the eye?

Answer 19

medial rectus
inferior rectus
superior rectus

Question 20

Which extraocular muscles abduct the eye?

Answer 20

lateral rectus
superior oblique
inferior oblique

Question 21

Which extraocular muscles depress the eye?

Answer 21

inferior rectus

superior oblique

Question 22

Which extraocular muscles elevate the eye?

Answer 22

superior rectus

inferior oblique

Question 23

Which extraocular muscles medially rotate the eye?

Answer 23

superior rectus
superior oblique
inferior rectus

Question 24

Which extraocular muscles laterally rotate the eye?

Answer 24

inferior oblique

Question 25

Which extraocular muscles are innervated by CN VI?

Answer 25

lateral rectus

Question 26

Which extraocular muscles are innervated by CN IV?

Answer 26

superior oblique

Question 27

Which extraocular muscles are innervated by CN III?

Answer 27

all except lateral rectus and superior oblique

Question 28

Where is the common tendinous ring (annulus of Zinn)?

Answer 28

surrounds the optic canal

Question 29

What muscles arise from the common tendinous ring?

Answer 29

the 4 rectus extraocular muscles + superior oblique (basically all but inferior oblique)

Question 30

Describe the function of the ciliary muscle.

Answer 30

Changes shape of lens. When ciliary muscle contracts, zonular fibers relax and lens thickens. When ciliary muscle relaxes, zonular fibers tauten and lens thins.

Question 31

What is the innervation of the ciliary muscle?

Answer 31

parasympathetics of CN III

Question 32

What produces aqueous humor?

Answer 32

ciliary body

Question 33

What muscles control the size of the pupil?

Answer 33

sphincter pupillae: contracts to reduce pupil diameter | dilator pupillae: contracts to increase pupil diameter

Question 34

What is the innervation of the sphincter and dilator pupillae?

Answer 34

sphincter: parasympathetic dilator: sympathetic (both of CN III)

Question 35

How many photoreceptors are in the optic disc?

Answer 35

none - blind spot where CN II exits the eyeball

Question 36

What is the site of highest acuity vision?

Answer 36

fovea centralis

Question 37

What are the 3 chambers of the globe?

Answer 37

anterior chamber posterior chamber vitreous chamber

Question 38

What artery supplies blood to the contents of the orbit?

Answer 38

ophthalmic artery, a branch of the internal carotid

Question 39

What artery supplies the retina?

Answer 39

central artery of the retina

Question 40

What arteries supply the globe?

Answer 40

anterior and posterior ciliary arteries

Question 41

What artery supplies the lacrimal gland, conjunctiva, and eyelids?

Answer 41

lacrimal artery

Question 42

What nerve fibers participate in the corneal reflex?

Answer 42

somatic sensory fibers carry sensation to brain along the long & short ciliary nerves, nasociliary nerve, and ophthalmic nerve branchial motor efferent fibers from CN VII innervating the orbiculari oculi muscle cause it to contract, closing the eyelid

Question 43

What nerve fibers participate in the pupillary light reflex?

Answer 43

special sensory sensations are carried by CN II visceral motor parasympathetic fibers are carried by the inferior division of CN III and the parasympathetic root of the ciliary ganglion; they synapse; post-ganglionic fibers travel along short ciliary nerves into globe to pupillary constrictor muscle, causing the iris to constrict