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Anatomy > Orbit > Flashcards

Orbit Flashcards

0
Q

What are the superior and inferior fornices?

A

Where the bulbar and palpebral conjunctiva meet

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1
Q

What are the two conjunctiva of the eye and what do they cover?

A

. Palpebral conjunctiva
. Bulbar conjunctiva
. palpebral part covers inside of eyelids and bulbar part covers the sclera and cornea

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2
Q

What is the plica semilunaris?

A

Medial fold of conjunctiva near the lacrimal lake

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3
Q

What is the iris and where is it found?

A

. It is a contractile diaphragm

. It lies on the anterior surface of the lens

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4
Q

What is the pupil and which muscles control the diameter?

A

. The pupil allows for the transmission of light

. Sphincter pupillae and dilator pupillae

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5
Q

What are the tarsal plates?

A

. Dense bands of CT that strengthen the eyelids

. There are superior and inferior tarsal plates

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6
Q

What are the medial and lateral palpebral ligaments?

A

They connect the superior/inferior tarsal plates to the medial/lateral angels of the eye

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7
Q

What is the orbital septum?

A

Weak membrane that spans from the tarsal plates to the margins of the orbit and becomes continuous with the periosteum

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8
Q

What are the 5 layers of the eyelid?

A 
. Skin
. Subcutaneous
. Muscular (orbicularis oculi, levator palpebrae superioris)
. Tarsofacial (tarsal glands and plate)
. Conjunctival (palpebral conjunctiva)
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9
Q

The lacrimal gland is split into two parts (which parts) by what structure?

A

. Levator palpebrae superioris
. Superior (orbital)
. Inferior (palpebral)

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10
Q

What type of fibers is the lacrimal gland stimulated by, and where do they originate from?

A

Para/post fibers from the pterygopalatine ganglion (PPG)

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11
Q

Describe the innervation of the lacrimal gland.

A

Superior salivatory nucleus gives off VE para/pre fibers that run through the greater petrosal nerve (has ss-taste from soft palate) of CN VII. The greater petrosal nerve meets up with the deep petrosal nerve (sym/post) to make the vidian nerve. The vidian nerve then goes to the PPG, where para/pre fibers synapse. From the PPG, the para/post fibers run through the pterygopalatine nerve to V2 to zygomatic nerve (branch of V2) to communicating branch to lacrimal nerve (branch of V1) to the lacrimal gland

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12
Q

Describe the course of tear drainage

A

Lacrimal gland to lacrimal ducts to superior/inferior fornices… then tears collect at the lacrimal lake and then drain through the lacrimal punctum on the lacrimal papilla. They then go through the lacrimal canaliculi to the lacrimal sac, which leads to the nasolacrimal duct and the nasal cavity

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13
Q

Where is the lacrimal caruncle?

A

Small mound of modified skin tissue in the lacrimal lake

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14
Q

Bones forming the orbit are lined with ________, which forms the _____________ of the eyeball.

A

Periorbita, fascial sheath

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15
Q

Where does the fascial (bulbar) sheath course on the actual eyeball?

A

Optic nerve to the corneoscleral junction

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16
Q

Expansions of the fascial sheath at the medial and lateral rectus muscles are called:

A

Medial and lateral check ligaments

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17
Q

What is the suspensory ligament of the eye?

A

Blending of the medial/lateral check ligaments with the fascia of the inferior rectus and inferior oblique

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18
Q

What is the tubular sheath?

A

The fascial sheath is pierced by the extraocular muscle tendons and is reflected onto each of them as the tubular sheath

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19
Q

All of the extraocular muscles are innervated by _______ except?

A

CN III, superior oblique (CN IV) and lateral rectus (CN VI)

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20
Q

The fovea is _________ to the optic disc (blind spot)

A

lateral

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21
Q

What are the three axes of rotation of the eyeball?

A

. Anteroposterior
. Vertical
. Horizontal

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22
Q

Which two muscles are responsible for elevating the eyeball? What axis of rotation is this?

A

. Superior rectus
. Inferior oblique
. Horizontal axis

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23
Q

Which two muscles are responsible for depressing the eyeball? What axis of movement is this?

A

. Inferior rectus
. Superior oblique
. Horizontal axis

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24
Q

Which three muscles abduct the eye and what axis of movement is this?

A

. Lateral rectus
. Superior oblique
. Inferior oblique
. Vertical axis

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25
Q

Which three muscles adduct the eye? What axis of movement is this?

A

. Medial rectus
. Superior rectus
. Inferior rectus
. Vertical axis

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26
Q

Which two muscles are responsible for lateral rotation and what axis of movement is this?

A

. Inferior rectus
. Inferior oblique
. Anteroposterior axis

27
Q

Which two muscles are responsible for medial rotation and what axis of movement is this?

A

. Superior rectus
. Superior oblique
. Anteroposterior axis

28
Q

What hole does CN II pass through, what fibers does it carry, whats the name of the artery that runs through it?

A

. Optic canal
. Special sensory (SS) for vision
. Central artery of the retina

29
Q

What hole does CN III course through and what does it innervate?

A

. Superior orbital fissure

. extraocular muscles except superior oblique and lateral rectus

30
Q

What are the functional components of CN III

A

It carries SE (somatic motor) and SA (somatic sensory) fibers

31
Q

What are the two divisions of CN III and describe their functional components

A

. Superior division - SE, SA, sym/post (goes to Muller’s muscle)
. Inferior division - SE, SA, para/post (goes to ciliary body and sphincter pupillae)
. VE para/pre fibers (from Edinger-Westphal) that course through the inferior division of CN III to reach the ciliary ganglion and synapse. VE para/post fibers then course through the short ciliary nerves

32
Q

Trochlear nerve (CN IV): hole, innervation, functional components

A

. Innervates the superior oblique muscle
. SE (somatic motor) and SA (somatic sensory)
. Superior orbital fissure

33
Q

What nerve does the opthalmic nerve branch from and what are its branches (medial to lateral)?

A

. It is a trigeminal branch, V1 specifically
. Nasociliary
. Frontal (then divides into supratrochlear and supraorbital nn.)
. Lacrimal

34
Q

Opthalmic nerve: hole, functional components, functional components cell bodies location

A

. Superior orbital fissure
. SA (somatic sensory)
. Trigeminal ganglion (SA fiber cell bodies are located here)

35
Q

Where does the nasociliary nerve course and what are its branches?

A

. Courses from lateral to medial over the optic nerve
. Long ciliary
. Posterior ethmoidal
. Anterior ethmoidal
. Infratrochlear (the nasociliary changes names to infratrochlear)

36
Q

What are the functional components of the nasociliary nerve and which branch has extra functional components?

A

. SA (somatic sensory)

. The long ciliary nerve also has VE sym/post fibers that innervate the dilator pupillae muscle

37
Q

Abducent nerve (CN VI): hole, innervation, functional components

A

. Superior orbital fissure
. SE (somatic motor and SA (somatic sensory)
. Lateral rectus

38
Q

What is the main artery of the orbit? What does it branch from?

A

. Opthalmic artery

. It is the only artery off of the ICA

39
Q

What are the 9 branches off of the opthalmic artery?

A 
. Central artery of the retina
. Lacrimal
. Long/short posterior ciliary
. Supraorbital
. Posterior/anterior ethmoidal
. Dorsal nasal
. Supratrochlear
40
Q

What are the major veins of the orbit and where do they drain?

A

. Superior opthalmic vein drains into the cavernous sinus

. Inferior opthalmic vein drains into the superior opthalmic vein and the pterygoid venous plexus

41
Q

What are the three layers of the eyeball from superficial to deep?

A

. Fibrous
. Vascular
. Inner (retinal)

42
Q

The fibrous layer contains what two structures? What are they responsible for?

A

. Cornea covers the anterior 1/6 of the eye. It is responsible for refraction of light entering the eye.
. Sclera covers the posterior 5/6 of the eye. It provides shape and attachment sites for muscles.

43
Q

What three structures are present in the vascular (pigmented) layer of the eye?

A

. Choroid
. Ciliary body
. Iris

44
Q

What is the choroid?

A

. It nourishes the retina

. It has an outer pigmented layer and an inner vascular layer which invests the posterior 5/6 of the eye

45
Q

What is the ciliary body?

A

. Muscular and vascular structure that connects the choroid and iris and provides attachment for the lens
. Folds on its internal surface (ciliary processes) secrete aqueous humor that fills the anterior and posterior chambers

46
Q

What is the ciliary muscle?

A

. Smooth muscle innervated by parasympathetic fibers
. It controls the thickness of the lens
. When the ciliary muscles are relaxed, the lens is stretched and set at distant vision

47
Q

What is the iris?

A

. Thin contractile diaphragm with a central aperture known as the pupil (allows in varying degrees of light)

48
Q

What are the two muscles in the iris?

A

. Sphincter pupillae - smooth muscle innervated by parasympathetics
. Dilator pupillae (more lateral)- smooth muscle innervated by sympathetics

49
Q

What are the two layers of the retina and what do they do?

A

. Inner neural layer = light receptive layer that has three types of neurons (rod/cones, bipolar cells, ganglion cells)
. Outer pigmented layer = single layer of cells that reinforce the light absorbing properties of the choroid

50
Q

Which cell type axons in the neural layer of the retina forms the optic nerve?

A

Ganglion cell axons

51
Q

What is the fundus?

A

The posterior part of the eye

52
Q

What is the optic disc?

A

. Optic nerve and central retina vessels are found there

. Blind spot

53
Q

What is the macula lutea?

A

It encircles the fovea centralis, which is the area of most acute vision

54
Q

Describe the cornea and its innervation

A

. Refracts the light that enters the eye
. Innervated by V1 fibers of the ciliary nerves
. Avascular

55
Q

How is the lens attached to the ciliary bodies?

A

. Zonular fibers

56
Q

Aqueous humor versus vitreous humor

A

. Aqueous humor fills the anterior and posterior compartments of the eye. Produced by the ciliary processes and nourishes lens and cornea
. Vitreous humor fills the vitreous chamber. Holds retina in place, supports the lens, and transmits light

57
Q

Innervation and function of levator palpebrae superioris

A

. Elevates the upper eyelid

. Superior division of CN III

58
Q

Innervation and function of superior rectus

A

. Elevates, adducts, and medially rotates eyeball

. Superior division of CN III

59
Q

Innervation and function of inferior rectus

A

. Depresses, adducts, and laterally rotates eyeball

. Inferior division of CN III

60
Q

Innervation and function of medial rectus

A

. Adducts eyeball

. Inferior division of CN III

61
Q

Innervation and function of lateral rectus

A

. Abducts eyeball

. CN VI

62
Q

Innervation and function of superior oblique

A

. CN IV

. Depresses, abducts, and medially rotates eyeball

63
Q

Innervation and function of inferior oblique

A

. Elevates, abducts, and laterally rotates eyeball

. Inferior division of CN III

64
Q

Lateral rotation? Medial rotation?

A

. Medial = superior rectus and superior oblique

. Lateral = inferior rectus and inferior oblique

65
Q

Where is the ciliary ganglion located and what are the functional components?

A

. Lateral edge of the optic nerve near the lateral rectus

  1. Motor root: para/pre fibers from inferior division of CN III
  2. Sensory root: SA fibers which join the nasociliary nerve (V1)
  3. Sympathetic root: sym/post fibers from the superior cervical ganglion via the carotid plexus which course with the opthalmic artery
66
Q

Short ciliary nerves: where are they from, what do they innervate, what are their functional components

A

. From the ciliary ganglion
. Enter eyeball carrying para/post, SA, sym/post fibers
para/post = innervate ciliary body and sphincter pupillae
SA = sensory from eyeball
sym/post = innervate blood vessels

Anatomy (13 decks)

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