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Ocular Anatomy 1 > EOM > Flashcards

EOM Flashcards

1
Q

What embryology origin is EOM?

A

Mesodermal

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2
Q

When does EOM development begin? When are they in their final anatomical positions?

A
  • 3 weeks of gestation

- 6 months of gestation (continues enlarging throughout gestation)

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3
Q

How are EOMS different from other skeletal muscles?

A

EOM have denser blood supply

  • connective tissue has more elastic fibers
  • have fewer fibers per unit, so more fine movements
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4
Q

Due to a unique combination of white and red muscle fibers, what are EOMS?

A

Fast and fatigue resistant

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5
Q

What are the two layers of EOM?

A
  1. Orbital layer: superficially near the orbital wall (inserted on a pulley)
  2. Globar layer (located deeper, becomes contiguous with tendon to insert on the globe)
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6
Q

What is the primary action of medial rectus? Lateral rectus?

A

Medial:ADDuction
Lateral:ABDuction

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7
Q

List primary, secondary, and tertiary actions of SR

A

1: Elevation
2. Intorsion
3. ADDuction

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8
Q

List the primary, secondary, and tertiary functions of IR

A

1: depression
2. Extorstion
3. ADDuction

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9
Q

List the primary, secondary, and tertiary actions of SO

A
  1. Intorsion
  2. Depression
  3. ABDuction
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10
Q

List the primary, secondary, and tertiary actions of IO

A
  1. Extortion
  2. Elevation
  3. ABDuction
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11
Q

Where do all recti muscles originate?

A

Annulus of Zinn

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12
Q

List the annulus of Zinn tendon attachments

A

SR: upper limb annulus
MR: upper and lower limbs
IR: lower limb
LR: upper and lower limbs

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13
Q

Annulus encloses the oculomotor foramen, what passes through this?

A
  • oculomotor nerve
  • optic nerve
  • ophthalmic artery
  • abducens nerve
  • nasociliary nerve
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14
Q

What is the spiral of tillaux?

A

-where recti muscles insert onto the sclera

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15
Q

Name the recti muscles in their order from closest to limbus to furthest

A
  1. Medial rectus
  2. inferior
  3. Lateral
  4. superior
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16
Q

What is the shortest muscle?

A

Inferior oblique

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17
Q

What is the longest and thinnest muscle?

A

Superior oblique

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18
Q

Where does the levator palpebrae superioris originate?

A

Orbital surface of lesser wing of sphenoid

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19
Q

What does the superior lamina of the lesser palpebrae superioris do? Inferior lamina?

A

Superior: voluntary to skin and upper eye lid
Inferior: involuntary to upper margin of superior tarsus

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20
Q

Name the superior muscles in order from superior to inferior

A

Levator
SR
SO

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21
Q

What is the strongest EOM and most eye turns are because of this?

A

Medial rectus

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22
Q

What is the only EOM to have it an atomic organ in the ANTERIOR orbit?

A

inferior oblique

23
Q

What is the action of the check ligaments?

A

Provide stops to excessive movements

24
Q

What are check ligaments?

A

Dense connective tissue network that connects EOM sheath to one another

25
Q

MR is anchored to periorbita by what? LR?

A

MR: medial check ligaments
LR: lateral check ligaments

26
Q

What is the suspensory ligament of lockwood?

A

Hammock between the medial and lateral check ligaments that suspends the globe
-inferior rectus and inferior oblique contribute

27
Q

What is primary gaze?

A

Eyes aligned around Sagittarius and horizontal plane, head erect, focus at infinity

28
Q

What is secondary gaze?

A

Rotation around a single flick axis

29
Q

What is tertiary gaze?

A

Rotation around both horizontal and vertical axes

30
Q

What is the X axis?

A

Horizontal axis (elevation and depression)

31
Q

What is the y axis?

A

Anterior to posterior. Torsion movements

32
Q

What is Z axis?

A

Vertical axis, adduction and abduction

33
Q

What are functions?

A

Movement involving one eye

34
Q

How many duction movements are there?

35
Q

What are versions?

A

Conjugate movement of both eyes in the same direction

36
Q

How many positions of gaze with version movements are there?

A

8 (9 cardinal positions of gaze)

37
Q

What is vergences?

A

Disjunctive movement of both eyes (in opposite direction

38
Q

What is convergence?

A

Both eyes looking inward

39
Q

What is divergence?

A

Both eyes looking outward

40
Q

What is the movement of IO?

A

-looking laterally and upward

41
Q

What is the movement of SO?

A

Looking laterally and down

42
Q

What si the movement of LR?

A

Looking laterally

43
Q

What is the movement of MR?

A

Looking medially

44
Q

What is the movement of SR?

A

Looking up and medially

45
Q

What is the movement of the IR?

A

Looking down and medially

46
Q

Which EOM is innervates by superior division of oculomotor

47
Q

Which EOM are innervates by inferior division of oculomotor?

48
Q

Lateral rectus innervation

49
Q

Superior oblique innervation

50
Q

Which EOM get blood supply from superior lateral branch of ophthalmic artery>

A

SR, LR, SO

51
Q

Which EOM get blood from inferior branch of ophthalmic artery?

52
Q

What EOM get drained by superior ophthalmic vein?

A

SR and MR (even though its the biggest vein)

53
Q

What EOMs get drained by inferior ophthalmic vein?

Ocular Anatomy 1 (5 decks)

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