Anatomy

Question 1

What are the 3 layers and their constituents

Answer 1

Fibrous tunic - sclera and cornea
Vascular - Iris, ciliary body, choroid
Retina - pigment and neuro

Question 2

What accumulates in the sclera

Answer 2

Bilirubin

Question 3

How many layers of sclera

Answer 3

3 - episcelra, sclera proper (collagen) and lamina fusca (pigment)

Question 4

How many bones in orbital wall

Answer 4

7

Question 5

Floor?

Answer 5

Maxilla, palatine and zygomatic

Question 6

What makes the roof

Answer 6

Frontal and lesser wing of sphenoid

Question 7

Medial wall?

Answer 7

Ethmoid, maxillary and sphenoid

Question 8

Lateral wall?

Answer 8

Zygomatic, greater wing of sphenoid

Question 9

What are the holes there?

Answer 9

Optic canal, greater and lesser orbital fissure

Question 10

Which is the thinnest part of the orbital wall?

Answer 10

Medial orbital , but is strengthened by the ethmoid sinuses

Question 11

Which is the most vulnerable part?

Answer 11

Floor - blow out fracture

Question 12

What can you see in a blow out fracture

Answer 12

Down and depressed gaze, cannot look up due to Inferior recurs dysfunction

Question 13

What is below the skin eyelid?

Answer 13

Orbicularis occuli - helps eyelid closure and release lacrimal gland secretion

Question 14

Which nerve is it innervated by

Answer 14

Facial nerve (7)

Question 15

What is the next layer?

Answer 15

Orbital septum

Question 16

What is the grading used for orbital cellulitis

Answer 16

Chandlers

Question 17

What’s next

Answer 17

Superior and inferior tarsal plates

Question 18

What is in these plates and what do they do

Answer 18

Melbomian glands and they produce the lipid layers of the tears

Question 19

What’s next

Answer 19

Levator apparatus

Question 20

What are they innervated by

Answer 20

CN 3

Question 21

What does this have

Answer 21

The superior and inferior tarsal muscles and levator palpabrae superioris

Question 22

What happens in complete ptosis

Answer 22

Paralysis of the levator palpabrae superioris due to lesion in cn 3 (in the cavernous sinus due to vascular aneurysm)

Question 23

What happens in partial ptosis

Answer 23

Paralysis of superior tarsal muscle which is innervated by sympathetic chain - Horners syndrome

Question 24

Where do the punctums drain into?

Answer 24

Canaliculi

Question 25

What does the common cancaliculi form?

Answer 25

Lacrimal sac

Question 26

Where does that drain?

Answer 26

Nasolacrimal duct, which drains into turbunates

Question 27

What are the layers of the cornea?

Answer 27

Anterior epithelium Bowman's membrane Corneal stroma - regular collagen fibers - no vasculature, but well innervated Descemet's membrane Endothelium - involved in fluid and ion balance - this is lost in corneal dystrophy leading to corneal opacity

Question 28

What are the glands on the conjunctiva called?

Answer 28

Krause and Wolfring

Question 29

What are the 3 segments of the conjucntiva

Answer 29

bulbar, fornix and palpebral

Question 30

What kind of anesthetic can be injected

Answer 30

Sub tenon block on the tenon capsule in the conjunctiva for cataract surgery

Question 31

What are the branches of the aorta

Answer 31

Aortic arch Brachiocephalic trunk on the right Common carotid on the left - breaks into internal and external carotid arteries Subclavian on the left

Question 32

What are the branches of the external carotid artery

Answer 32

8 branches - Some ancient lovers find old positions more stimulating

Question 33

Anterior circulation of the brain is supplied mostly by what

Answer 33

ICA

Question 34

Posterior circulation of the brain is supplied mostly by what

Answer 34

Vertebral arteries branching off the subclavian

Question 35

What do the vertebral arteries merge into

Answer 35

Basilar artery - joins the posterior circle of Willis

Question 36

What is amaurosis fugax

Answer 36

TIA of the eye, its like a curtain coming down but is painless

Question 37

What is the management

Answer 37

Aspirin, clopidogrel (anti-platelets) | Steroid if it is GCA

Question 38

Trace the visual pathway

Answer 38

Photoreceptors to bipolar cells to ganglion cells to optic nerve to LGN to visual cortex

Question 39

What can cause unilateral field loss

Answer 39

Optic nerve compression

Question 40

Homonymous hemianopia

Answer 40

Right cerebrovascular event

Question 41

macular sparing homonymous hemianopia

Answer 41

Stroke - This happens as the macula received dual blood supply