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Ophthalmology > Orbit and Eye Screencast > Flashcards

Orbit and Eye Screencast Flashcards

1
Q

What are the six bones that make up the orbit?

A

Frontal, zygomatic, sphenoid, ethmoid, lacrimal, maxilla

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2
Q

What bones have orbital plates?

A

Frontal, ethmoid and maxillary = smoother and flatter areas of bone

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3
Q

Why are the maxillary and ethmoid orbital plates likely to fracture?

A

The bone is thin

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4
Q

What structures pass through the optic canal?

A

The optic nerve and ophthalmic artery

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5
Q

What passes through the supraorbital notch?

A

The supraorbital neurovascular bundle

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6
Q

What division does the supraorbital nerve belong to?

A

CN V1

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7
Q

What passes through infraorbital foramen?

A

Infraorbital neurovascular bundle

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8
Q

What division does the infraorbital nerve belong to?

A

CN V2

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9
Q

What shape is the orbit?

A

Pyramidal = faces anteriorly (has different axis from eyeball)

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10
Q

What is the base of the orbit called?

A

The orbital rim

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11
Q

What makes up the apex of the orbit?

A

The sphenoid bone

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12
Q

What is the benefit of the supraorbital margin overhanging the infraorbital margin?

A

It protects the eye (bones of this area is also thick)

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13
Q

What occurs in a blowout fracture?

A

The thicker bones stay intact but the thinner bones fracture = medial wall and orbital floor are common sites

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14
Q

What occurs in a trapdoor fracture?

A

Soft tissue structures pass through the fractures

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15
Q

Where do the bones on the outside of the orbit tend to fracture?

A

At sutures

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16
Q

What makes up the most superficial layer of the eyelid?

A

The orbicularis oculi = has orbital and palpebral parts

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17
Q

What is the orbital part of the orbicularis oculi?

A

Area around the entire outside of the orbit = carries out tight closure of eye

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18
Q

What is the palpebral part of the orbicularis oculi?

A

Covers the actual eyelid = carries out gentle closure of eye

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19
Q

What nerve innervates the orbicularis oculi?

A

CN VII

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20
Q

What makes up the deep layer of the eyelid?

A

Superior and inferior tarsus, tendon of LPS, lateral and medial palpebral ligaments, orbital septum

21
Q

What are the inferior and superior tarsus?

A

Fibrous skeleton = thickened bands of connective tissue

22
Q

Where are the lateral and medial palpebral ligaments located?

A

On either side of the tarsus

23
Q

What is the function of the orbital septum?

A

Prevents spread of infection from superficial to deep and holds orbital contents in place

24
Q

What is the orbital septum made of?

A

Tough connective tissue

25
Q

What is the action of the levator palpebrae superioris?

A

Lifts upper part of the eye

26
Q

What is the superior tarsus muscle?

A

Slip of smooth muscle that comes off of the levator palpebrae superioris = also called Mueller’s muscle

27
Q

What does the superior tarsus muscle do?

A

Helps widen the eye = under sympathetic control

28
Q

Where are the tarsus glands located?

A

Within the tarsus = Meibomian glands

29
Q

What do the tarsus glands secrete?

A

Secrete lipids = cover bottom of eyelids to prevent lacrimal overflow

30
Q

What do the lacrimal glands produce?

A

Lacrimal fluid (tears)

31
Q

What is the flow of lacrimal fluid?

A

Wash over eye, pushed towards medial angle by blinking, drains through lacrimal puncta, eventually reaches inferior meatus

32
Q

Where is the lacrimal gland located?

A

In the lacrimal fossa

33
Q

What innervates the lacrimal glands?

A

Parasympathetic innervation from CN VII

34
Q

Where do tears collect?

A

Collect in lacrimal lake = then pass through puncta into canaliculi

35
Q

What is the first part of the nasolacrimal duct?

A

Lacrimal sac

36
Q

How many extra-ocular muscles are there?

A

7 = 4 rectus muscles, 2 oblique muscles and the levator palpebrae superioris

37
Q

Where do the rectus muscles pass?

A

Run from orbit straight onto the eyeball

38
Q

What are the rectus muscles?

A

Superior and inferior, medial and lateral

39
Q

What are the oblique muscles?

A

Superior and inferior = insert onto eyeball at oblique angle and attach more posterior than rectus muscles

40
Q

What does the superior oblique muscle pass through?

A

The trochlea = loop of connective tissue which acts as a pulley to turn the muscle

41
Q

Where do the rectus muscles originate from?

A

Common tendinous ring (annulus) = anterior to optic canal

42
Q

Where do the rectus muscles insert on to?

A

The sclera

43
Q

Where does the superior oblique muscle originate from?

A

The sphenoid bone

44
Q

Where does the inferior oblique originate from?

A

Orbital plate of maxilla

45
Q

Where does the levator palpebrae superioris originate from and insert onto?

A 
Origin = lesser wing of sphenoid
Insertion = skin and superior tarsus
46
Q

What nerve innervates the lateral rectus muscle?

A

CN VI

47
Q

What muscle does CN IV innervate?

A

Superior oblique muscle

48
Q

What muscles does CN III innervate?

A

Inferior oblique, superior and inferior rectus, medial rectus, levator palpebrae superioris

Ophthalmology (20 decks)

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