Orbit Flashcards

1
Q

Functions of the eyelid?

A

Protect eyelid, spread lacrimal secretions across surface and shade eyelid

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2
Q

What is the palpebral fissure?

A

Space between the corners of the eyes (medial and lateral canthi) – opening of eyelids basically

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3
Q

Where is the ciliary gland located?

A

Within the subcutaneous tissue of the eye

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4
Q

What results from ciliary gland infection?

A

Sty

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5
Q

Origin, insertion, innervation and action of levator palpebrae superioris

A

O: lesser wing of sphenoid
I: Skin of upper eyelid and tarsal plate
IN: oculomotor nerve (III)
Action: elevate eyelid

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6
Q

Origin, insertion, innervation and action of superior oblique

A

O: Body of sphenoid
I: Through trochlea to sclera
IN: Trochlear nerve (IV)
Action: Depress and ABduct eye

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7
Q

Origin for the rectus muscles?

A

Common tendinous ring

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8
Q

Insertion for the rectus muscles?

A

Sclera posterior to cornea

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9
Q

One rectus muscle not innervated by oculmotor nerve?

A

Lateral rectus - abducens nerve (VI)

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10
Q

Ptosis?

A

Drooping of upper eyelid

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11
Q

What can cause complete ptosis?

A

Destruction of the oculomotor nerve or one of its branches to levator palpebrae superioris

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12
Q

What muscle originates at the lesser wing of the sphenoid but inserts on the tarsal plate of upper lid?

A

Tarsal muscle (of Muller)

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13
Q

What causes slight ptosis?

A

Paralysis of tarsal muscle

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14
Q

Symptoms of Horner’s syndrome?

A
Paralysis of tarsal muscle
Slight ptosis
Miosis
Enopthalmos
Anhidrosis and blushing
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15
Q

Pupillary constriction due to paralysis of dilator pupillae muscle

A

Miosis

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16
Q

Posterior displacement of the eye

A

Enopthalmos

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17
Q

Inability to sweat normally

A

Anhidrosis

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18
Q

What innervates the tarsal muscle?

A

Post-ganglionic fibers (smooth muscle)

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19
Q

What is the palpebral fascia comprised of?

A

Tarsus and orbital septum

20
Q

What does the palpebral fascia attach to?

A

Medial and lateral palpebral ligaments

21
Q

Membrane that lines back of eyelids?

A

Palpebral conjunctiva

22
Q

Thin, transparent membrane that attaches to eyeball?

A

Bulbar conjunctiva

23
Q

Describe how tears drain?

A
  • Lacrimal gland
  • Lacrimal ducts
  • Lacrimal canaliculi
  • Lacrimal sac
  • Nasolacrimal duct
    • Drains into inferior nasal meatus/turbinate
24
Q

Bones that make up the orbit?

A

Frontal, zygomatic, maxilla, lacrimal, sphenoid, ethmoid, palatine

25
Q

If bones in the orbit are fractured what can occur?

A

Intracanalicular portion of optic nerve now vulnerable to ischemia due to loss of blood supply

26
Q

What runs in the optic canal?

A

CN II and opthalmic artery

27
Q

Where do blow-out fractures occur?

A

Floor of the orbit

28
Q

What may result from a blow-out fracture?

A

Sensation loss below the eye where the infraorbital nerve would supply if it was damaged

29
Q

Le-Forte 1

A

Transverse fracture of maxilla only

30
Q

Le-Forte 2

A

Pyramid shaped fracture involving maxilla and medial orbit

31
Q

Le-Forte 3

A

Transverse fracture of many facial bones and orbits - usually separating face from base of skull

32
Q

What can cause a blow-out fracture?

A

Trauma to front of eyeball

33
Q

What are not cardinal positions of gaze?

A

Straight up and down

34
Q

What is the chief sensory nerve of the eye?

A

Nasociliary nerve from V1

35
Q

Describe the direct and consensual corneal reflexes?

A

Lightly touch cornea
Nasociliary nerve endings respond - afferent
Facial nerve response - efferent
Orbicularis oculi contracts to blink

36
Q

What nuclei are involved in the direct and consensual corneal reflexes?

A

Descending nucleus of V - sensory

Facial nucleus - motor

37
Q

Main blood supply to orbit?

A

Opthalmic artery

38
Q

Main blood supply to retina?

A

Central Artery of retina

39
Q

Terminal branches of opthalmic artery?

A

Dorsal nasal and supratrochlear

40
Q

Where does the opthalmic artery originate?

A

Internal carotid artery

41
Q

What vein in the eye drains into the cavernous sinus?

A

Superior opthalmic vein

42
Q

What are the 3 aspects of the triad of accommodation?

A

Convergence of vision
Pupillary constriction
Thickening of the lens

43
Q

Result of a syphilis infection; Pupils are unreactive to light but constrict during accommodation

A

Argyll-Robertson pupil

44
Q

Describe papilledema

A

INCREASED INTRACRANIAL PRESSURE restricts venous return from retina which causes swelling of optic disc

45
Q

Result of a lesion on ciliary ganglion; Initially pupil is unreactive to light but if convergence is maintained the pupil will slowly constrict

A

Holmes-Adie pupil