11: Orbit, Eye, And Eye Movement

Question 1

Palpebral portion vs lacrimal portion of orbicularis oculi: function

Answer 1

Palpebral portion: gentle closing of eyelid

Lacrimal portion: tight closing of eyelid, dilates lacrimal sac

Question 2

Levator palpebrae superioris O and I

Answer 2

O: lesser wing of sphenoid
I: tarsus / palpebral fascia and skin of upper lid

Question 3

Levator palpebrae superioris N

Answer 3

CN 3

Question 4

Tarsal muscle of muller O and I

Answer 4

O: lesser wing of sphenoid
I: tarsal plate of upper lid

Question 5

Tarsal muscles innervation

Answer 5

Symp fibers from T1 (smooth muscles btw)

Question 6

Horner’s syndrome

Answer 6

Paralysis of tarsal muscle, causing slight ptosis (also miosis, enophthalmos, anhydrosis, and bruising of skin on face

Question 7

Location of lacrimal gland

Answer 7

Lacrimal fossa of orbit, with some protruding into the upper lid, otherwise on top of LR and LPS muscles

Question 8

Lacrimal ducts

Answer 8

6-10 small ducts that drain into superior fornix

Question 9

Path of tears draining from surface of eye

Answer 9

1. Lacrimal canaliculi
2. Common sinus
3. Lacrimal sac
4. Nasolacrimal duct
5. Inferior meatus of nasal cavity

Question 10

Lacrimal punctilious

Answer 10

Openings of the lacrimal canaliculi

Question 11

MOI for blow-out fracture

Answer 11

Trauma to front of eyeball, depressed fracture of zygomatic which is displaced medially

Question 12

What structures can be herniated in a blow out fracture, and where would they herniate into?

Answer 12

Periorbita, IO, IR, orbital fat pad -> into maxillary sinus

Question 13

Which three nerves are used by both symp and parasymp nerves to innervate the lacrimal gland?

Answer 13

Maxillary N, lacrimal N, zygomatic N

Question 14

Which type of nerve synapses in the sphenopalatine ganglion on the way to innervate the lacrimal gland, symp or parasymp?

Answer 14

Parasymp synapse there

Question 15

Origin of all extraocular muscles besides inferior oblique

Answer 15

Annulus tendinius

Question 16

Three major nerves to the orbit (all from V1)

Answer 16

Lacrimal N, frontal N, nasociliary N

Question 17

Two branches of the lacrimal N

Answer 17

Zygomaticofacial, zygomaticotemporal N

Question 18

Two branches of the frontal N

Answer 18

Supraorbital N, supratrochlear N

Question 19

Three branches of the nasociliary N

Answer 19

Long ciliary N’s, posterior ethmoidal N, infratrochlear N

Question 20

Main sensory N to the eyeball

Answer 20

Long ciliary N’s

Question 21

Where is the ciliary ganglion?

Answer 21

Lateral to the optic nerve in the orbit

Question 22

Three components of the triad of accommodation

Answer 22

1. Convergence of gaze
2. Pupillary constriction
3. Thickening of lens

Question 23

What muscles help with convergence of gaze

Answer 23

Medial recti

Question 24

How does the lens thicken for near vision?

Answer 24

Ciliary zonule fibers relax, due to ciliary muscle contraction

Question 25

Chief artery to the orbit

Answer 25

Ophthalmic A

Question 26

Two terminal branches of the ophthalmic A

Answer 26

Supratrochlear A, dorsal nasal A

Question 27

Two major branches of the ophthalmic A that supply the optic N

Answer 27

Posterior ciliary A, central retinal A

Question 28

Chief blood supply to the retina

Answer 28

Central retinal A

Question 29

Ciliary muscles

Answer 29

Circularly arranged smooth muscles around the lens

Question 30

Where do nerves to the ciliary muscles come from?

Answer 30

Ciliary ganglion

Question 31

Sphincter pupillae vs dilator pupillae muscles

Answer 31

Sphincter pupillae: circularly arranged for constricting pupil Dilator pupillae: radially arranged for dilating pupil

Question 32

Innervation to sphincter pupillae and dilator pupillae muscles

Answer 32

Sphincter pupillae: parasymp from ciliary ganglion | Dilator pupillae: symp from ciliary ganglion

Question 33

Papilledema

Answer 33

Edema of the optic disc, causing extension of the subarachnoid space around the optic N

Question 34

What causes papilledema

Answer 34

Increased intracranial pressure (is a medical emergency)

Question 35

Hymphema

Answer 35

Presence of blood in anterior chamber

Question 36

What causes hyphema

Answer 36

Trauma/rupture of greater arterial circle of the iris (medical emergency)

Question 37

Subconjunctival hemorrhage

Answer 37

Bleeding in subconjunctival tissue

Question 38

What causes subconjunctival hemorrhage

Answer 38

Rupture of deep pericorneal plexus

Question 39

What causes conjunctivitis

Answer 39

Inflammation of superficial pericorneal plexus

Question 40

Argyll-Roberson pupil

Answer 40

Pupils in reactive to light, but constrict during accommodation

Question 41

What causes Argyll-Roberson pupil

Answer 41

Syphilis -> destruction of pretectum

Question 42

Traumatic optic neuropathy

Answer 42

Ischemia of the intracanalicular portion of CN3

Question 43

Hydrocephaly can cause..?

Answer 43

Compression of CN 6 in cavernous sinus