orbit/radiology

Question 1

roof of the orbit

Answer 1

orbital plate of the frontal bone

Question 2

lateral wall of the orbit

Answer 2

zygomatic bone and greater wing of sphenoid

Question 3

floor of the orbit

Answer 3

-orbital plate of the maxilla, which separates the orbital cavity from the maxillary sinus

Question 4

medial wall of the orbit

Answer 4

• frontal process of the maxilla
• lacrimal bone
• orbital plate of the ethmoid, and the body of the sphenoid

Question 5

where do eyelids meet eachother?

Answer 5

-medial and lateral angles

Question 6

palpebral fissure

Answer 6

-opening between the eyelids and the entrance into the conjunctival sac

Question 7

what covers the deep surface of the eyelid?

Answer 7

-mucous membrane called the conjuncitva

Question 8

tarsal glands

Answer 8

• modified sebaceous glands that open into the margin of the eyelid behind the eyelashes
• secrete oily substance to prevent tear overflow

Question 9

orbital septum

Answer 9

• fibrous sheet that supports the eyelids

- attached to periosteum at oribital margins

Question 10

tarsal plates

Answer 10

• thicked orbital margins

- tarsal glands are embedded in them

Question 11

parts of the lacrimal gland

Answer 11

• large orbital part

- small palpebral part

Question 12

preganglionic parasympathetic innervation of lacrimal apparatus

Answer 12

• from lacrimal nucleus of facial nerve

- travel greater petrosal nerve and nerve of pterygoid canal to synapse in pterygopalatine ganglion

Question 13

Postganglionic parasympathetic innvervation of lacrimal apparatus

Answer 13

• leave pterygopalatine ganglion and travel V2(maxillary of trigeminal)
• reach lacrimal gland by lacrimal nerve

Question 14

sympathetic postganglionic innervation of lacrimal apparatus

Answer 14

• from internal carotid plexus(T1-L2)

- join deep petrosal nerve and nerve to pteryoid canal to travel with preganglionic para

Question 15

lacus lacimalis

Answer 15

• tears circulate across cornea and accumualte here

- lake of tears

Question 16

lacrimal duct path

Answer 16

• lacrimal punctum to lacrimal canaliculi
• to lacrimal sac
• to nasolacrimal duct
• to inferior meatus of the nose

Question 17

what surrounds the optic nerve?

Answer 17

• meninges

- nerve pierces sclera and meninges fuse with the sclera

Question 18

CSF and optic nerve

Answer 18

• held in subarachnoid space

- pressure within cranial cavity is transmitted to the back of the eye

Question 19

opthalmic division of trigeminal nerve : branches

Answer 19

• frontal
• lacrimal
• nasociliary nerves

Question 20

frontal nerve

Answer 20

-divides into supraorbital and supratrochlear to supply skin of forehead

Question 21

lacrimal nerve

Answer 21

joined by branch of zygomaticotemporal nerve to go to lacrimal gland and lateral, upper eyelid

Question 22

Oculomotor supplies which EOM?

Answer 22

-all but superior oblique and lateral rectus

Question 23

Lateral rectus nerve supply

Answer 23

-CN VI(abducens)

Question 24

Superior oblique nerve supply

Answer 24

-CNIV(trochlear)

Question 25

opthalmic artery is a branch of...

Answer 25

-internal carotid artery

Question 26

branches of opthalmic artery

Answer 26

- central artery of the retina - muscular branches - ciliary arteries - lacrimal artery - subraorbital and trochleat arteries

Question 27

Central artery of the retina

Answer 27

-runs within the optic nerve and enters the eye at the center of the optic disc

Question 28

superior ophthalmic vein

Answer 28

-communicates in front with facial vein

Question 29

Inferior ophathalmic vein

Answer 29

-communicates through inferior orbital fissure with pterygoid venous plexus

Question 30

where do ophthalmic veins drain?*****

Answer 30

cavernous sinus

Question 31

ciliary ganglion receives preganglionic fibers from...

Answer 31

-oculomotor nerve via nerve to inferior oblique

Question 32

ciliary ganglion sends postganglionic fibers to...

Answer 32

-back of the eye for sphincter pupillae and cilary muscle

Question 33

dilation of the eye

Answer 33

- postganglionic sympathetic fiber | - levator palpebrae superioris or occipitofrontalis

Question 34

constriction of eye

Answer 34

- postganglionic para fiber - sphincter - occipital orbis

Question 35

25 year old male presents to the ER with head trauma. Diagnostic test of choice?

Answer 35

-CT brain WITHOUT contrast

Question 36

Which imaging modality of the brain causes no radiation exposure to the patient?

Answer 36

MRI

Question 37

55 year old female presents to the ER with unilateral weakness, onset 30 minutes ago. Initial diagnostic test of choice?

Answer 37

-CT brain WITHOUT contrast

Question 38

Why would you want to do an initial CT without contrast?

Answer 38

- contrast shows up white, and so does blood. so you cant tel bleeding - contrast can stay in the head for a while too so you cannot monitor bleed

Question 39

when would you use CT WITH contrast?

Answer 39

- in assessment of abnormal enhancement patterns | - masses and vascular abnormality

Question 40

what does MRI use as imaging?

Answer 40

-DWI

Question 41

what is MRI good at looking at?

Answer 41

-acute ischemia

Question 42

why would you not just start with an MRI?

Answer 42

-you have to eliminate the idea of a hemorrhage before you cant look into ischemia

Question 43

who would you not want to do an MRI on?

Answer 43

- pacemaker - metal residues/orjects - claustrophobia

Question 44

is MRI done with or without contrast?

Answer 44

both

Question 45

what kind of contrast is used in CT?

Answer 45

-iodine based

Question 46

what kind of contrast is used in MRI?

Answer 46

- Gd (Gadolinium) | - not iodine based

Question 47

what are the options for assessment of cerebral vasculature?

Answer 47

- CTA - MRA - ultrasound - digital angio

Question 48

how would you get around someone having a contrast allergy?

Answer 48

harvard prep medication

Question 49

where do aneurysms normally happen on circle of willis?

Answer 49

-anterior communicating artery

Question 50

what is the advantage of MRA?

Answer 50

-you do not need contrast

Question 51

what is the clearest image for cerebral vasculature?

Answer 51

CTA

Question 52

how should blood flow? antegrade or retrograde?

Answer 52

antegrade

Question 53

what would cause retrograde?

Answer 53

-subclavian steal syndrome

Question 54

what gives you the highes radiation for cerebral vasaculature?

Answer 54

digital angio

Question 55

what are your options for spinal column?

Answer 55

- CR - CT - MRI

Question 56

what is the initial assessment of trauma to the neck/ spine?

Answer 56

CR

Question 57

what is the best imaging option for spinal cord?

Answer 57

-MRI

Question 58

what do you suspect if there is subdural hematoma and chronic hermatoma in a child?

Answer 58

-shaken baby syndrome and child abuse