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Flashcards in orbit/radiology Deck (58)
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1
Q

roof of the orbit

A

orbital plate of the frontal bone

2
Q

lateral wall of the orbit

A

zygomatic bone and greater wing of sphenoid

3
Q

floor of the orbit

A

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

4
Q

medial wall of the orbit

A
  • frontal process of the maxilla
  • lacrimal bone
  • orbital plate of the ethmoid, and the body of the sphenoid
5
Q

where do eyelids meet eachother?

A

-medial and lateral angles

6
Q

palpebral fissure

A

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

7
Q

what covers the deep surface of the eyelid?

A

-mucous membrane called the conjuncitva

8
Q

tarsal glands

A
  • modified sebaceous glands that open into the margin of the eyelid behind the eyelashes
  • secrete oily substance to prevent tear overflow
9
Q

orbital septum

A
  • fibrous sheet that supports the eyelids

- attached to periosteum at oribital margins

10
Q

tarsal plates

A
  • thicked orbital margins

- tarsal glands are embedded in them

11
Q

parts of the lacrimal gland

A
  • large orbital part

- small palpebral part

12
Q

preganglionic parasympathetic innervation of lacrimal apparatus

A
  • from lacrimal nucleus of facial nerve

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

13
Q

Postganglionic parasympathetic innvervation of lacrimal apparatus

A
  • leave pterygopalatine ganglion and travel V2(maxillary of trigeminal)
  • reach lacrimal gland by lacrimal nerve
14
Q

sympathetic postganglionic innervation of lacrimal apparatus

A
  • from internal carotid plexus(T1-L2)

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

15
Q

lacus lacimalis

A
  • tears circulate across cornea and accumualte here

- lake of tears

16
Q

lacrimal duct path

A
  • lacrimal punctum to lacrimal canaliculi
  • to lacrimal sac
  • to nasolacrimal duct
  • to inferior meatus of the nose
17
Q

what surrounds the optic nerve?

A
  • meninges

- nerve pierces sclera and meninges fuse with the sclera

18
Q

CSF and optic nerve

A
  • held in subarachnoid space

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

19
Q

opthalmic division of trigeminal nerve : branches

A
  • frontal
  • lacrimal
  • nasociliary nerves
20
Q

frontal nerve

A

-divides into supraorbital and supratrochlear to supply skin of forehead

21
Q

lacrimal nerve

A

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

22
Q

Oculomotor supplies which EOM?

A

-all but superior oblique and lateral rectus

23
Q

Lateral rectus nerve supply

A

-CN VI(abducens)

24
Q

Superior oblique nerve supply

A

-CNIV(trochlear)

25
Q

opthalmic artery is a branch of…

A

-internal carotid artery

26
Q

branches of opthalmic artery

A
  • central artery of the retina
  • muscular branches
  • ciliary arteries
  • lacrimal artery
  • subraorbital and trochleat arteries
27
Q

Central artery of the retina

A

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

28
Q

superior ophthalmic vein

A

-communicates in front with facial vein

29
Q

Inferior ophathalmic vein

A

-communicates through inferior orbital fissure with pterygoid venous plexus

30
Q

where do ophthalmic veins drain?*****

A

cavernous sinus

31
Q

ciliary ganglion receives preganglionic fibers from…

A

-oculomotor nerve via nerve to inferior oblique

32
Q

ciliary ganglion sends postganglionic fibers to…

A

-back of the eye for sphincter pupillae and cilary muscle

33
Q

dilation of the eye

A
  • postganglionic sympathetic fiber

- levator palpebrae superioris or occipitofrontalis

34
Q

constriction of eye

A
  • postganglionic para fiber
  • sphincter
  • occipital orbis
35
Q

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

A

-CT brain WITHOUT contrast

36
Q

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

A

MRI

37
Q

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

A

-CT brain WITHOUT contrast

38
Q

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

A
  • 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
39
Q

when would you use CT WITH contrast?

A
  • in assessment of abnormal enhancement patterns

- masses and vascular abnormality

40
Q

what does MRI use as imaging?

A

-DWI

41
Q

what is MRI good at looking at?

A

-acute ischemia

42
Q

why would you not just start with an MRI?

A

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

43
Q

who would you not want to do an MRI on?

A
  • pacemaker
  • metal residues/orjects
  • claustrophobia
44
Q

is MRI done with or without contrast?

A

both

45
Q

what kind of contrast is used in CT?

A

-iodine based

46
Q

what kind of contrast is used in MRI?

A
  • Gd (Gadolinium)

- not iodine based

47
Q

what are the options for assessment of cerebral vasculature?

A
  • CTA
  • MRA
  • ultrasound
  • digital angio
48
Q

how would you get around someone having a contrast allergy?

A

harvard prep medication

49
Q

where do aneurysms normally happen on circle of willis?

A

-anterior communicating artery

50
Q

what is the advantage of MRA?

A

-you do not need contrast

51
Q

what is the clearest image for cerebral vasculature?

A

CTA

52
Q

how should blood flow? antegrade or retrograde?

A

antegrade

53
Q

what would cause retrograde?

A

-subclavian steal syndrome

54
Q

what gives you the highes radiation for cerebral vasaculature?

A

digital angio

55
Q

what are your options for spinal column?

A
  • CR
  • CT
  • MRI
56
Q

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

A

CR

57
Q

what is the best imaging option for spinal cord?

A

-MRI

58
Q

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

A

-shaken baby syndrome and child abuse