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PART ONE REVISION. > ORBIT & OCULAR ADNEXAE - Orbital Blood Vessels > Flashcards

ORBIT & OCULAR ADNEXAE - Orbital Blood Vessels Flashcards

1
Q

Where does the ophthalmic artery arise from?

A

Arises from medial aspect of ICA medial to the anterior clinoid process at foramen lacerum junction (ICA passes through here)

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2
Q

Fill in the blanks.

A
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3
Q

What is the first branch of the ophthalmic artery?

A

central retinal artery.

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4
Q

What is the route of the central retinal artery?

A

Travels below optic nerve

then pierces upwards around the dural sheath and arachnoid of optic nerve 12mm behind globe and gives off some small pial branches.

then travels within the optic nerve through to the lamina cribrosa into the retina at nasal side of optic disc.

Then divides into superotemporal, superonasal, inferotemporal and inferonasal branches to supply INNER SIX layers of retina.

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5
Q

What supplies the fovea?

A

Ciliary/choroidal circulation.

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6
Q

What is the route of the ophthalmic artery?

A

INFERIOR to optic nerve —> LATERAL to optic nerve —> LATERAL COMPARTMENT –> above optic nerve to MEDIAL COMPARTMENT –> superiorly –> towards medial orbit.

travels inferior to optic nerve, then takes a turn and goes lateral to optic nerve.

Gives two branches at lateral compartment here,
1. the lacrimal artery (runs above lateral rectus and supplies lacrimal gland).
2. recurrent meningeal artery - travels in lateral part of SOF and anastamoses with middle meningeal artery (branch of ECA)

after going laterally, ophthalmic artery travels above optic nerve and reaches medial compartment of the orbit passing below superior rectus. Gives branch here the posterior ciliary arteries either side of the optic nerve (lateral and medial PCA).

As ophthalmic artery travels above optic nerve it gives one branch (supraorbital arteries) and two more braches: medial and lateral mscular artery.

It now encounters the medial wall of orbit and gives rise to two arteries - anterior and posterior ethmoidal arteries (which passes through their foramen respectively)

It then travels anteriorly in medial compartment and gives rise to its terminal branches at the trochlea of the superior oblique - dorsal nasal and supratrochlear artery.

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7
Q

Name the main branch of the lacrimal artery.

A

the lateral palpebral artery - supplies the eyelids.

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8
Q

What is the route of the medial and lateral posterior ciliary arteries?

A

Divide into short and long posterior ciliary arteries.

Some short arteries form plexus around optic disc form Zinn of Haller.

Long posterior Passes in suprachoroidal space all along until the ciliary body where anastomoses with anterior ciliary artery to form the major arterial circle of iris.

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9
Q

What is the circle of Zinn and Haller?

A

plexus formed between the posteiror ciliary arteries above the optic nerve head –>

the PCA is main source of blood supply to optic nerve head and adjacent retrolaminar part of optic nerve

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10
Q

What is the cause of anterior ischaemic optic neuropathy?

A

Results from non-perfusion/hypoperfusion of the ciliary blood supply to the optic nerve head –> usually results in sectoral disc oedema and altidunal field defect as either the superior or inferior portion is affected (the cilioretinal blood supply is SEGMENTAL)

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11
Q

What do the short posterior ciliary arteries supply?

A

Short posterior ciliary arteries supply the outer 4 layers of the retina (RPE, photoreceptors, ELM and outer nuclear layer)

Supply intraocular part of optic nerve

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12
Q

What do the long posterior ciliary arteries supply?

A

choroid (anterior to the equator), ciliary body and iris (outer 4 layers of retina).

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13
Q

Where does the long posterior ciliary artery terminate?

A

Long posterior pierce the sclera oblique and enter suprachoroidal space reaching the ciliary body where anastomoses with anterior ciliary artery to form the major arterial circle of iris.

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14
Q

What is the difference between the short and the long posterior ciliary arteries? (2)
1. Difference in number
2. Difference in branches

A
  1. number - LPCA (2) , SPCA (2)
  2. branches - LPCA (0) , SPCA (10-20)
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15
Q

What is the route of the supraorbital artery?

A

accompanies supraorbital nerve and travels just below orbital roof and above superior rectus and LPS and leaves through the supraorbital notch.

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16
Q

What is the difference between the medial and lateral muscular arteries?

A

Medial muscular : supplied medical aspect - medial rectus, inferior rectus and inferior oblique

Lateral muscular artery: supplies LPS, and lateral rectus and superior rectus, superior oblique.

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17
Q

What are the terminal branches of the muscular arteries (medial and lateral)?

A

The anterior ciliary artery

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18
Q

How many anterior ciliary arteries are there?

A

7 anterior ciliary arteries - 2 for each recti, one for the lateral rectus

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19
Q

What is the route of the anterior ciliary artery?

A

Pierces sclera near the limbus to enter the ciliary body and form the major arterial circle with the long posterior ciliary artery 4mm from the lmbus.

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20
Q

What does the anterior ciliary artery supply?

A

Supply sclera, conjunctiva, limbus and extraocular muscles.

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21
Q

What forms the major and minor arterial circles?

A

Major: anastamoses of long posterior ciliary artery and anterior ciliary artery around the iris.

Minor: branches from major run radially into iris as iris vessels and anastamose at pupillary margin forming minor arterial circle.

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22
Q

What arteries supply the anterior segment?

A

70% from anterior ciliary artery, 30% from posterior ciliary artery.

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23
Q

What are the risks of extraocular surgery from a vascular point of view? (2)

A
  1. ANTERIOR SEGMENT ISCHAEMIA - do not operate on more than 2 recti muscle in one eye in order not to damage the anterior ciliary arteries (which supply 70% of anterior segment)
  2. VERTICAL MUSCLES MORE RISKY - there are no posterior ciliary arteries on vertical plane so more risky.
24
Q

What are the branches of the dorsal nasal artery?

A

medial palepbral arteries - one for upper eyelid and one for lower eyelid.

25
Q

Where does the lateral palpebral artery come from?

A

lacrimal artery from ophthalmic artery

26
Q

What arteries form the superior and inferior marginal arcades of the eyelid? How many arcades are in the upper eyelid vs lower eyelid?

A

anastamoses of lateral and medial palpebral arteries. 2 in upper eyelid, one in lower eyelid.

27
Q

How many vortex veins are there?

A

4-7, usually 4.

Superior temporal and superior nasal vein

Inferior temporal and inferior nasal vein

28
Q

How far are the vortex veins away from the limbus?

A

They exit 14-25mm away from the limbus between rectus muscles.

29
Q

How long is the scleral canal where vortex veins travel into?

A

4mm

30
Q

The uvea firmly attached to the sclera at which positions? (2)

A
  1. Scleral sulcus
  2. Ampulla of vortex veins
31
Q

Where do the vortex veins drain into?

A

Superior vortex veins –> superior ophthalmic vein

inferior vortex veins –> inferior ophthalmic vein

join with central retinal vein to the cavernous sinus.

32
Q

How far does the central retinal artery pierce the dura in relation to the globe?

A

12mm.

33
Q

What arteries supplies the surface nerve fibre layer of the optic nerve?

A

retinal arterioles of the central retinal artery.
20% of patients will have cilioretinal artery supply from short posterior ciliary artery.

34
Q

What supplies the prelaminar region of the optic nerve?

A

Short posterior ciliary artery

35
Q

What supplies the laminar region (lamina cribrosa) of the optic nerve?

A

Short posterior ciliary artery and the arterial circle of Zinn

36
Q

What supplies the retrolaminar region of the optic nerve?

A

pial plexus from central retinal arteries and from posterior ciliary arteries.

37
Q

What vessel supplies the intracanalicular part of the optic nerve?

A

The ophthalmic artery

38
Q

What vessel supplies the intracranial part of the optic nerve? (4)

A
  1. recurrent branch of anterior superior hypophyseal artery (supplies inferior optic nerve)
  2. anterior cerebral artery (supplies superior optic nerve)
  3. ophthalmic artery
  4. anterior communicating artery
39
Q

What is the course of the internal carotid artery?

A

picture

40
Q

Which hole does the internal carotid artery go through?

A

Foramen lacerum

41
Q

What are the branches of the ophthalmic artery?

A

picture

42
Q

What are the structures lateral to the ophthalmic artery as it enters the lateral component of the orbit? (4) What branch does it give here?

A
  1. Ciliary Ganglion
  2. III nerve
  3. VI nerve
  4. Lateral rectus

Gives a lacrimal branch –> lacrimal artery
Lacrimal artery gives branch lateral palpebral artery which supplies lateral side of eyelids

43
Q

What branches does the ophthalmic artery give in the lateral compartment of the orbit? (2)

A

Gives a lacrimal branch –> lacrimal artery
Lacrimal artery gives branch lateral palpebral artery which supplies lateral side of eyelids

Recurrent meningeal artery –> travels in lateral SOF and anastamoses with middle meningeal artery (branch of external carotid artery)

44
Q

What structures accompany the ophthalmic artery as it travels above the optic nerve in the medial compartment of the orbit? (2)

A
  1. Superior ophthalmic vein
  2. Nasociliary nerve
45
Q

What branches does the ophthalmic artery give off in the medial compartment of the orbit?

A

Posterior ciliary artery –> divides into lateral and medial posterior ciliary arteries.

the long posterior ciliary arteries travel in the suprachoroidal space and reach ciliary body and form the major anastamosis

46
Q

What do the short posterior ciliary arteries do?

A

Pierce sclera and supply choroid in segmental manner
Some branches form anastamotic ring around optic disc –> circle of Zinn-Haller

47
Q

Which branch of the ophthalmic artery travels above the optic nerve and just superior to the LPS and superior rectus just below orbital roof and exits at the supraorbital notch?

A

Supraorbital artery (accompanied with supraorbital nerve)

48
Q

Which branches of the ophthalmic artery branch off just superior to optic nerve?

A

MUSCULAR ARTERIES
1. Medial muscular artery - MR, IR, IO
2. Lateral muscular artery - SR, LPS, LR, SO
These further subdivide into anterior ciliary arteries

49
Q

What is the anterior portion of the optic radiation supplied by?

A

anterior choroidal artery

50
Q

What does the supraorbital artery supply?

A

SR, SO, LPS, upper eyelid forehead and scalp

51
Q

What does the anterior ethmoidal artery supply?

What does the posterior ethmoidal artery supply?

A

Supply the ethmoid sinus, nasal cavity and skin of nose.

52
Q

What does the inferior ophthalmic vein receive drainage from? Where does it send its drainage to?

A

Facial and angular veins

Sends drainage to cavernous sinus and pterygoid plexus

53
Q

What is the route of the superior ophthalmic vein?

A

See picture

54
Q

Which extraocular muscles receive auxillary blood supply? What are they? (3)

A

lateral rectus - lacrimal artery

inferior rectus/inferior oblique - infraorbital artery from maxillary artery (ECA)

55
Q

Where do these nerves and arteries originate from and what is their supply:
1. supraorbital nerve
2. infraorbital nerve
3. supratrochlear nerve
4. supraorbital nerve

  1. supraorbital artery
  2. infraorbital artery
  3. supratrochlear artery
  4. infratrochlear artery
A
  1. supraorbital N - frontal nerve - CNV1 - supplies upper eyelid, conjunctiva, forehead and frontal sinus
  2. infraorbital N - CNV2 - supplies lower eyelids, nose, cheek and upper lip.
  3. Supratrochlear N - frontal nerve - CNV1 - supplies upper eyelid, conjunctiva and forehead
  4. infratrochlear N - nasociliary nerve - CNV1- supplies eyelids, conjunctiva, lacrimal sac and nose skin.
  5. supraorbital artery - ophthalmic artery (superior compartment) - travels with nerve above LPS and SR and enters supraorbital notch - supplies SR, SO, LPS, upper eyelid forehead and scalp
  6. infraorbital artery - maxillary artery (ECA) - passes through IOF in floor of orbit, passes through groove and canal with the infraorbital nerve to supply lower eyelid and anastmoses with dorsal nasal (terminal branch of ophthalmic)
  7. supratrochlear artery - terminal branch of ophthalmic artery to supply forehead, scalp

8.infratrochlear artery - not clinically important.

PART ONE REVISION. (80 decks)

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