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SFII Test 1 > Orbit > Flashcards

Orbit Flashcards

1
Q

What movements do the eyes make to compensate for head tilt and what are the muscles responsible?

A

Involuntary rotational movements - medial and lateral rotation

Oblique muscles (superior and inferior)

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2
Q

What are the voluntary movements of the eye and muscles responsible?

A

Abduction/Adduction

Elevation/Depression

Rectus muscles (Superior, Inferior, Lateral, Medial)

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3
Q

What is the tendinous ring? (And what is the associated exception?)

A

Ring of connective tissue surrounding the optic canal and superior orbital fissure

Location of origin of most extraocular muscles

**Inferior oblique takes origin from the floor of the orbit

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4
Q

What are the actions of the superior and inferior rectus?

A

Superior rectus - raise, adduct, medially rotate

Inferior rectus - lower, adduct, laterally rotate

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5
Q

What are the actions of the superior and inferior oblique muscles?

A

Superior oblique - Lower, abduct, medially rotate

Inferior oblique - raise, abduct, laterally rotate

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6
Q

What does the resting position of the eye depend on, and what happens when there is damage to any one muscle?

A

The tonic activities of the muscles

Weakness of movement (depending on muscle); does NOT completely eliminate movement

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7
Q

What results from damage to CN VI?

A

Medial Strabismus (i.e. cross-eyed)

Dur to damage/paralysis of the lateral rectus

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8
Q

What results from damage to CN IV?

A

Inability to turn eye down and out

Patient compensates by tilting head to the opposite side

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9
Q

What results from damage to CN III?

A

Lateral Strabismus (i.e. wall-eyed) due to paralyzed medial rectus

Ptosis (Drooping eyelid) due to paralyzed Lev. Palp. Sup.

Dilated pupil (Mydriasis) due to paralyzed pupillary constrictor

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10
Q

What results from damage to the ciliary ganglion or short ciliary nerves?

A

Loss of parasympathetics of CN III

Mydriasis - dilated pupil

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11
Q

What is a blown pupil and what does it indicate?

A

Maximally dilated pupil

Indicates catastrophe - stroke, herniation, etc.

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12
Q

What are the Roof, Lateral, and Floor boundaries of the orbit?

A

Roof - Frontal bone

Lateral Wall - Zygomatic and Sphenoid

Floor - Maxiallary

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13
Q

What is the medial wall of the orbit comprised of?

A

Maxillary, Lacrimal, Ethmoid, Frontal, and Sphenoid bones

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14
Q

What foramina allow structures to enter the orbit?

A

The optic canal and superior orbital fissure

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15
Q

What two pathways allow structures to exit the orbit? (Excluding to nasal cavity)

A

Supraorbital notch

Infraorbital foramen

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16
Q

What pathways connect the orbit and the nasal cavity?

A

Anterior and Posterior ethmoidal foramina

Nasolacrimal duct

17
Q

Describe the layers of the eyelid.

A

Skin - eyelashes and openings of sebaceous glands

Subcutaneous - CT that contains sebaceous glands

Obicularis Oculi (Palpebral part) - closes eye

18
Q

What is a stye or horde’olum?

A

Obstruction or infection of sebaceous gland in the subcutaneous layer of the eyelid

19
Q

What is the tarsal plate?

A

Fibrous CT “skeleton” of the eyelid

Contains Tarsal glands that keep tears in the eye and prevent their evaporation

20
Q

What is a Chalazion?

A

Obstruction of the tarsal gland

21
Q

What is the orbital septum?

A

CT layer continuous with periosteum of the orbit

22
Q

What is the function of the medial and lateral check ligaments?

A

Prevent excessive rotation

23
Q

What is astigmatism?

A

Irregularities of the cornea

24
Q

What major arteries supply the eye and where do they originate?

A

Central artery of the retina

Posterior ciliary arteries (long and short)

Originate from the ophthalmic artery

25
Q

What do the posterior ciliary arteries supply?

A

Pierce the sclera, blood to the choroid, photoreceptors

26
Q

What does the central artery of the retina supply?

A

Neural retina

*End artery

27
Q

Describe the choroid layer.

A

Highly vascular, pigmented

Provides oxygen, nutrients to photoreceptors

28
Q

What occurs as a result of central retinal artery occlusion?

A

Blindness in the occluded eye

Most common cause is carotid artery atherosclerosis

29
Q

Why can an increase in CSF pressure affect vision?

A

The dura and subarachnoid space extend around the optic nerve, and increase in pressure will push on the nerve.

Slow onset, headaches

30
Q

What is papilledema?

A

Swelling of the optic disc

31
Q

What is the dilator pupil?

A

Radial smooth muscle under sympathetic control

Dilates the pupil

32
Q

What is the constrictor pupil?

A

Circular smooth muscle under parasympathetic control (CN III)

Constricts the pupil

SFII Test 1 (25 decks)

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