Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Y1 - Neuroanatomy - Exam 2 > 5. Eye Movement > Flashcards

5. Eye Movement Flashcards

1
Q

three categories of eye movements:

A
  1. conjugate: eyes move in SAME direction
  2. vergence: focus shifts between near and far objects
  3. vestibulo-ocular: keeps target fixed on retina during head movements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

two types of conjugate eye movement

(eyes move in same direction)

A
  1. saccadic: rapid movement; vision moves from target to target
  2. smooth pursuit: maintains image of moving target fixed on the retina
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

two types of vergence eye movements:

eyes moving in opposite directions

A
  • convergence: visual axis of eyes CONVERGE (near focus)
  • divergence: visual axis of eyes DIVERGE (far focus)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

describe the eye movements when looking at a painting

(free examination)

A

saccadic eye movements;

  • tracing the attention given to the piece of art;
  • extra attention given to identifying the faces
  • more time spent on primary subjects
  • also may depend on what you ask the patient to look at
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

describe the eye movements when looking at a painting

(give the ages of people)

A
  • saccadic eye movements
  • Spending more time looking for visual cues of ages; looking at peoples’ faces
    • Still includes fast, saccadic movements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

list the type/# of extraocular muscles

A
  • 4 recti muscles
  • 2 oblique muscles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

which cranial nerves innervate the extraocular muscles?

A
  • CN III: oculomotor
  • CN IV: trochlear
  • CN VI: abducens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

oculomotor nerve (CN III)

innervates which extraocular muscles?

A
  • superior RECTUS
  • inferior RECTUS
  • medial RECTUS
  • inferior OBLIQUE
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

trochlear nerve (CN IV)

innervates which extraocular muscle(s)?

A

superior oblique muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

abducens nerve (CN VI)

innervates which extraocular muscle(s)?

A

LATERAL rectus muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

muscle for:

elevation and upgaze

A

superior rectus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

muscle for:

ADDUCTION of th eye; pulls nasal/medial direction

A

medial rectus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

muscle for:

depression, downgaze

A

inferior rectus muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

muscle for:

ABduction of the eye; lateral gaze/or temporal gaze

A

abducens nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

brainstem gaze centers:

to gaze towards RIGHT

A
  1. Left frontal eye cortex –>
  2. left medial longitudinal faciculus –>
  3. right abducens nucleus:
    • innervates right abducens nerve –> R lateral rectus mm.
    • innervates left oculomotor nerve–> L medial rectus mm.
  4. Overall fxn: shifts gaze to right
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the brainstem gaze centers,

and where are they located?

A
  1. horizontal gaze center – PONS (think: bridge)
  2. vertical gaze center – MIDBRAIN (think: “V”)
  3. vergence gaze center – MIDBRAIN (think: “micky mouse sign”)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

brainstem gaze centers:

define

A

collections of neurons serving extraocular muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is/where is the horizontal gaze center?

A
  • paramedian pontine reticular formation, also known as PPRF or paraabducens nucleus
  • found in the pons
19
Q

fxn and how does the PPRF

(paramedian pontine reticular formation) work?

A
  • involved in the coordination of eye movements, particularly horizontal gaze and saccades
  • flow of information:
    1. frontal eye fields: plays an important role in the control of visual attention and eye movements
    2. PPRF
      • medial longitudinal fasciculus (MLF) –> oculomotor nerve –> Left medial rectus
      • abducens nerve –> Right lateral rectus
20
Q

CC: MLF (medial longitudinal fascicululs)

syndrome

A

aka: internuclear ophthalmoplegia

impacting internuclear pathway, and innervation from cortex –> abducens is still in tact, but communication between 2 cranial nerve nuclei is what is interrupted;

common in demyelinated diseases, such as multiple sclerosis

21
Q

where is the vertical gaze center located?

where do fibers cross?

A
  • located in rostral midbrain
  • fibers cross at posterior commissure, w/ pineal gland in close proximity
22
Q

where does vertical gaze center project to?

what is its function?

A
  • projects to oculomotor subnuclei
  • projects to muscles that do vertical motion: superior and inferior recti muscles
23
Q

where is the vergence gaze center located?

where does it project to?

A
  • located in rostral midbrain (reticular formation)
  • projects to:
    • CN III (convergence)
    • CN VI (divergence)
24
Q

which cranial nerve is associated w/ CONVERGENCE?

A

CN III

(oculomotor)

25
Q

which cranial nerve is associated w/ DIVERGENCE?

A

CN IV

trochlear

26
Q

what are the cortical gaze centers?

A
  • FEF: frontal eye field
  • PEF: parietal
  • OEF: occipital
  • TEF: temporal
27
Q

frontal eye field:

fxn and projection

A
  • fxn: origin of saccadic eye movements
  • project to vertical and horizontal gaze centers & to superior colliculus
28
Q

what does parietal eye field influence?

A

influence saccadic movements

29
Q

what does temporal eye field influence?

A

influences smooth pursuit

30
Q

occipital eye fields:

fxn, and action

A
  • the origin of vergence movements
  • focus shifts: faraway object <–> near target
    • signal to oculomotor or abducens nuclei
31
Q

CC: strabismus

A

(eyes are not aligned) / aka Cranial Nerve VI palsy
Lateral rectus is NOT working, so the medial rectus is pulling inwards

32
Q

CC: Patient is cross-eyed and has trouble navigating stairs

A

vestibular testing indicates the patient has strabismus;

this is CN VI palsy (one eye looks directly at the object you are viewing, while the other eye is misaligned inward (esotropia, “crossed eyes” or “cross-eyed”), outward (exotropia or “wall-eyed”), upward (hypertropia) or downward (hypotropia).

33
Q

how would you describe the location of the misaligned globe?

which muscle/cranial nerve is affected?

A

The LEFT eye is elevated and ADDUCTED

the superior oblique muscle is affected;

CN IV (trochlear nerve)

34
Q

what is the normal movement for the superior oblique muscle?

A

“down and out”

by the tochlear nerve

35
Q

cranial nerve IV supplies which superior oblique?

which tendon is associated?

A

it is the TROCHLEAR nerve; CN IV

tendon of superior oblique

36
Q

actions of superior oblique?

A

primary action is intorsion (medial rotation);

secondary is ABduction and DEPRESSION

(inward and downward)

37
Q

innervation and action of the inferior oblique muscle?

A

cranial nerve (III): oculomotor nerve

extorsion, elevation, ABduction

38
Q

trochlea:

define

A

fascial sling in upper corner of the eye;

supports the superior trochlear muscle

39
Q

name the axes of the globes (eyeball) in the orbits (eyesockets)?

A

Red axis paralell to nose bridge - Axis of eyeball

Blue axis obliquely - Axis of orbit

40
Q

extraocular eye muscles and innervation

A

LR6 - SO4 - AO3

  • Lateral rectus: CN 6 (abducens)
  • Superior oblique: CN 4 (trochlear)
  • ALL OTHERS: CN 3 (oculomotor)
    • superior rectus
    • inferior rectus
    • medial rectus
    • inferior oblique
41
Q

primary actions of the extraocular muscles

A
  • Lateral rectus: ABDUCTION
  • Medial rectus: ADduction
  • Superior rectus: Elevation
  • Interior rectus: Depression
  • Superior oblique: Intorsion
  • Inferior oblique: Extorsion
42
Q

How to test the CN IV:

A

use the superior oblique to depress an ADDUCTED globe;

if patient is looking down to test superior oblique is working –> put the eye in an ADDucted position (and then see if it depresses the eye)

43
Q

what is the purpose of the extra-ocular muscles?

A

to allow the eyes to remain fixed on an object even when turning the head side to side (i.e. ear to shoulder)

44
Q

which cranial nerve palsy would result in a compensatory head tilt?

A

cranial nerve IV palsy –>

if the right eye is extorted and sl elevated causing double vision –>

to compensate the pt tilts head to the opposite side

Y1 - Neuroanatomy - Exam 2 (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions