Ocular: Orbital Vascular And Circulation

Question 1

What artery does the ophthalmic artery branch from?

Answer 1

Internal carotid artery

Question 2

How does internal carotid artery enter the skull?

Answer 2

Carotid canal

Question 3

How is the ophthalmic artery positioned relative to the optic nerve when it enters the orbit?

Answer 3

-lateral to the optic nerve in optic canal the courses overtop of nerve
-between MR and SO
**in 15% of people it goes under

Question 4

3 regions that branch off the ophthalmic artery:

Answer 4

-ocular
-orbital
-extra orbital

Question 5

What arteries are in the ocular region of the ophthalmic artery?

Answer 5

-central retinal artery
-ciliary arteries

Question 6

What branches does the central retinal artery give off?

Answer 6

-small pial branches

Question 7

What branches do the ciliary arteries give off?

Answer 7

Short and long posterior ciliary arteries

Question 8

Long posterior ciliary arteries give off…

Answer 8

Medial and lateral branches

Question 9

Short posterior ciliary arteries give off…

Answer 9

-10-20 branches
-may give rise to cilioretinal artery

Question 10

What arteries are in the orbital region of the ophthalmic artery?

Answer 10

-muscular arteries
-lacrimal artery

Question 11

Muscular arteries give off…

Answer 11

-7 anterior ciliary arteries (two to each rectus muscle except LR has one)

Question 12

Which rectus muscle only has one anterior ciliary artery?

Answer 12

Lateral rectus

Question 13

Lacrimal artery branches into:

Answer 13

-superior and inferior lateral palpebral arteries
-zygomatic artery and branches

Question 14

What branches does the extra orbital region of the ophthalmic artery give off?

Answer 14

-supraorbital artery
-post. Ethmoidal artery
-ant. Ethmoidal artery
-recurrent meningeal artery
-medial palpebral artery
-supratrochlear artery
-dorsonasal artery

Question 15

What are the terminal branches of the ophthalmic artery?

Answer 15

-supratrochlear
-dorsonasal

Question 16

What is the first branch of the ophthalmic artery?

Answer 16

Central retinal artery (first and the smallest)

Question 17

Course of central retinal artery and branches inside and outside the eye:

Answer 17

-branches inferior to optic nerve
-pierces dural sheath of optic nerve post. to sclera
-crosses subarachnoid space to enter substance of the nerve
-courses w/ central retinal vein
-crosses laminated cribrosa and enters the back of the eye
-small pial branches that supply pia

Question 18

What is the position of the central; retinal artery relative to the central retinal vein in the optic disc?

Answer 18

-emerges on nasal side of optic disc just nasal to the central retinal vein

Question 19

Lamina cribrosa is…

Answer 19

Very thin sclera

Question 20

How many muscular arteries are there?

Answer 20

4

Question 21

How many anterior ciliary arteries are there?

Answer 21

7

Question 22

What do anterior ciliary arteries do?

Answer 22

They supply the rectus muscles (2 branches for each except LR has only 1)

Question 23

Pathway of anterior ciliary arteries

Answer 23

-pierce sclera and join LPCA to form major arterial circle of iris

Question 24

Arterial circle of iris is located in the…

Answer 24

Ciliary body

Question 25

Anterior ciliary arteries can also stay on the surface to give rise to…

Answer 25

Conjunctival arteries

Question 26

What are the branches of the external carotid artery that supply orbital and peri-orbital structures?

Answer 26

-facial artery -infraorbital artery -superficial temporal artery

Question 27

Different paths of venous drainage:

Answer 27

-central retinal vein -vortex veins -anterior ciliary veins -infraorbital veins

Question 28

Where does superior ophthalmic vein drain?

Answer 28

Cavernous sinus

Question 29

Where does inferior ophthalmic vein drain?

Answer 29

-pterygoid venous plexus -superior ophthalmic vein -cavernous sinus

Question 30

Where is the superior ophthalmic vein located?

Answer 30

Outside the common tendinous ring, but in the SOF

Question 31

Where is inferior ophthalmic vein located?

Answer 31

Outside the common tendinous ring but inside the IOF

Question 32

What is a carotid-cavernous-sinus fistula?

Answer 32

Abnormal connection between carotid artery and cavernous sinus that leads to eye bulging, congestion, pulsing eyeball, headache, and droopy lid

Question 33

Main causes for carotid-cavernous-sinus fistula

Answer 33

Trauma, aneurysm, and others

Question 34

What is the main artery that supplies the eye?

Answer 34

Ophthalmic artery

Question 35

Two vascular systems that supply the eye:

Answer 35

-retinal -uveal: iris, ciliary body, choroid

Question 36

What two parts of the uveal vascular system are located anterior?

Answer 36

Iris and ciliary body

Question 37

What part of the uveal vascular is located posterior?

Answer 37

Choroid

Question 38

Where is the Blood-aqueous-barrier (BAB) located in the iris?

Answer 38

In the non-pigmented layer of the ciliary epithelium in the posterior iridal epithelium

Question 39

What prevents the blood from getting into the aqueous chamber?

Answer 39

Presence of tight junctions between endothelial cells

Question 40

Why is the choroidal vascular so important for photoreceptors?

Answer 40

It is th only source of blood supply to the photoreceptors!

Question 41

If blood supply to the photoreceptors was cut off…

Answer 41

The function would be compromised ad the cells may die

Question 42

Are the capillaries of the choriocapillaries fenestrated or non-fenestrated?

Answer 42

Fenestrated

Question 43

Why is the central retinal artery so important for the retina?

Answer 43

It provides small branches to optic nerve that supplies the inner layers of the retina

Question 44

Where is the inner blood-retina layer located?

Answer 44

-In the retinal vessels -made up of endothelial cells that line the blood vessels in retina

Question 45

Why are pericytes important?

Answer 45

The give strength to the capillary cell wall

Question 46

Where are pericytes located?

Answer 46

In tight junctions between endothelial cells apart of the blood-retina barrier

Question 47

What happens to pericytes in diabetic retinopathy?

Answer 47

Diabetic retinopathy causes hyperglycemia which causes loss of pericytes leading to intro retinal hemorrhage and exudates

Question 48

Location of outer blood-retina-barrier

Answer 48

Tight junctions between RPE cells

Question 49

Location of inner blood-retinal-barrier

Answer 49

-Tight junctions between endothelial cells of retinal vascular -include pericytes and glial cells