Orbit Anatomy Flashcards

1
Q

What bones make up the roof of the orbit?

A

orbital part of frontal bone, lesser wing of sphenoid

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2
Q

What bones make up the medial wall of the orbit?

A

ethmoid bone, frontal bone, lacrimal bone, sphenoid bone

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3
Q

What bones make up the inferior wall of the orbit?

A

maxilla, zygoma, palatine bone

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4
Q

What bones make up the lateral wall of the orbit?

A

zygoma, greater wing of sphenoid

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5
Q

What are the seven bones that contribute to the orbit?

A

maxilla, zygomatic, frontal, ethmoid, lacrimal, sphenoid, palatine

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6
Q

What travels through the optic canal?

A

optic nerve (CNII) and ophthalmic artery

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7
Q

What travels through the superior orbital fissure?

A
Lacrimal n.
Frontal n.
Trochlear n. 
Sup. Ophthalmic v. 
Sup. Div. of CN III
Nasociliary n. 
Inf. Div. of CN III
Abducent n. 
Inf. Ophthalmic v. 

*Mnemonic for nerves: Luscious French Torts Sit Nestled In Anticipation

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8
Q

What travels through the inferior orbital fissure?

A

orbital branches of V2–zygomatic nerve and infraorbital nerve; and infraorbital artery

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9
Q

The anterior and posterior ethmoidal foramina conduct what structures from where to where?

A

anterior and posterior ethmoidal nerves and vessels from orbit into ethmoid bone

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10
Q

What nerves synapse in the ciliary ganglion?

A

pre-ganglionic parasympathetics of CNIII destined for smooth muscle (constrictor pupillae and ciliary muscles) in the eyeball

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11
Q

The lacrimal artery is a branch off what artery?

A

ophthalmic artery

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12
Q

The anterior and posterior ethmoidal arteries are branches off what artery?

A

ophthalmic artery

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13
Q

What fibers travel with the short ciliary nerves?

A

post-ganglionic parasympathetics of CNIII
post-ganglionic sympathetics
GVA via V1

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14
Q

What are signs of loss of sympathetic innervation to the eyes?

A

anhydrosis, miosis, ptosis, enopthalmos (Horner’s syndrome)

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15
Q

What are signs of parasympathetic loss in the eyes?

A

loss of accommodation, mydriasis, loss of lacrimation

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16
Q

Where are the cell bodies of the ophthalmic nerve located?

A

trigeminal/semilunar ganglion

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17
Q

What are the 3 major branches of the ophthalmic (V1) nerve?

A

lacrimal nerve
frontal nerve
nasociliary nerve

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18
Q

The ophthalmic veins drain to what 2 vein(s)/sinus(es)?

A

cavernous sinus and pterygoid plexus

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19
Q

What is the Annulus of Zinn, aka tendinous ring?

A

a ring of fibrous tissue surrounding the optic nerve at its entrance at the apex of the orbit

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20
Q

The medial rectus moves the eyeball which direction?

A

medially

21
Q

The lateral rectus moves the eyeball which direction?

A

laterally

22
Q

The superior oblique moves the eyeball which direction?

A

down and out: depresses and lalterally rotates

23
Q

The inferior oblique moves the eyeball which direction?

A

up and out: elevates and laterally rotates

24
Q

The inferior rectus moves the eyeball which direction?

A

down and in: depresses and medially rotates

25
Q

The superior rectus moves the eyeball which direction?

A

up and in: elevates and medially rotates

26
Q

How do you test specific muscle of the orbit?

A

shorten the muscle you’re not interested in, then elevate/depress the eye depending on the muscle you are testing

27
Q

What four muscles of the orbit originate from the common tendinous ring?

A

superior rectus, medial rectus, inferior rectus, lateral rectus

28
Q

The superior branch of oculomotor nerve (CNIII) innervates what muscle(s)?

A

levator palpebrae superioris, superior rectus

29
Q

The inferior branch of oculomotor nerve (CNIII) innervates what muscle(s)?

A

medial rectus, inferior rectus, inferior oblique

30
Q

Dilation and constriction of the pupil are under antagonistic control by ___ and ___ efferents respectively

A

sympathetic; parasympathetic

31
Q

Pupillary constriction is under what autonomic control?

A

parasympathetic

32
Q

Contraction of the ciliary muscle ___(dec/inc) the size of the ring formed by the ___ ___. This ___(dec/inc) tension on the suspensory ligament of the lens.

A

decreases; ciliary body; decreases

33
Q

What types of fibers run in the long ciliary nerve?

A

sensory and sympathetic fibers coming from the nasociliary nerve

34
Q

What nerve carries pain from the eyeball, like when you get something in your eye?

A

V1-ophthalmic nerve

35
Q

What types of fibers run in the short ciliary nerve?

A

sensory, post-ganglionic sympathetic, and post-ganglionic parasympathetic

36
Q

Describe the corneal reflex.

A

something irritates the cornea, sensation is carried by V1-ophthalmic; synapse in the brain stem tells CN VII to orbicularis oculi orbit muscle to tightly shut the eye; eye reopened later by levator palpebrae superioris innervated by CNIII

37
Q

Describe sympathetic innervation of the lacrimal gland.

A

from thoracic chain - superior cervical ganglion - cervical plexus - become the deep petrosal nerve - join fibers of greater petrosal nerve to become nerve of the pterygoid canal; pass through pterygopalatine ganglion (no synapses) to innervate the lacrimal gland

38
Q

Describe parasympathetic innervation of the lacrimal gland.

A

pre-ganglionics: from superior salivatory nucleus; run in CN VII - greater petrosal nerve - nerve of pterygoid canal - synapse in pterygopalatine ganglion. Post-ganglionics: travel with maxillary nerve - zygomatic nerve - lacrimal branch of ophthalmic nerve, then innervate the gland

39
Q

What motion would be used to test the medial rectus muscle?

A

ask the patient to look medially

40
Q

What motion would be used to test the lateral rectus muscle?

A

ask the patient to look laterally

41
Q

What motion would be used to test the superior rectus muscle?

A

ask the patient to look laterally and up

42
Q

What motion would be used to test the inferior rectus muscle?

A

ask the patient to look laterally and down

43
Q

What motion would be used to test the superior oblique muscle?

A

ask the patient to look medially and down

44
Q

What motion would be used to test the inferior oblique muscle?

A

ask the patient to look medially and up

45
Q

The lateral rectus muscle is innervated by what nerve?

A

abducent nerve, CN VI

46
Q

The medial rectus muscle is innervated by what nerve?

A

oculomotor nerve, CN III

47
Q

The superior oblique muscle is innervated by what nerve?

A

trochlear nerve, CN IV

48
Q

The inferior and superior rectus muscles are innervated by what nerve?

A

oculomotor nerve, CN III