Brainscape's Knowledge GenomeTM

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


See full index

Ophthalmology > Neuro-Ophthalmology > Flashcards

Neuro-Ophthalmology Flashcards

1
Q

What fibres come together to form the optic nerve?

A

Retinal ganglion cell axons

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

Nasal axons of CNII form what part of the field of vision?

A

Temporal vision

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

CNII has four parts. What are they?

A

Intraocular
Intraorbital
Intracanalicular
Intracranial

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

Describe the intraocular CNII?

A

Shortest; 1mm

Exits posteriorly via the lamina cribrosa (scleral opening)

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

Describe the intraorbital CNII?

A

Longest; 25mm

Has myelinated covering. Ends at the optic foramen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the intracanalicular CNII?

A

Where the optic nerve exits the orbit through the optic canal to enter the middle cranial fossa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the intracranial CNII?

A

Ends at the optic chiasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where the the location of the optic chiasm?

A

Located anterior to the hypothalamus and usually directly superior to the pituitary gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the direction of inferonasal axons take in the chiasm

A

Turn anteriorly to the contralateral CNII (Willibrand’s knee)

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

Willibrand’s knee explains the visual field defect in anterior chiasm lesions. Describe it.

A

Junctional scotomas: ipsilateral optic neuropathy with contra-lateral superotemporal defects

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

How is the Circadian rhythm exerted on the eyes?

A

A few photosensitive retail ganglion cell axons connect with the suprachiasmatic nucleus of the hypothalamus

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

What is the optic tract?

A

Connects the optic chiasm with the lateral geniculate nucleus

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

What are the optic radiations?

A

Optic radiations connect the LGN to the occipital lobe

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

Superior optic radiations represent which visual field defects?

A

Inferior visual quadrants

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

Superior optic radiations pass thorough which brain lobe?

A

Parietal lobe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where do superior optic radiations terminate?

A

Primary visual cortex (V1/Brodmann area 17) in the occipital lobe

Superior to the calcarine sulcus (cuneus gyrus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the eponymous name of the inferior optic radiations?

A

Meyer’s loop

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

Inferior optic radiations represent which visual field defects?

A

Superior visual fields

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the journey of Meyer’s loop

A

Passes through the temporal lobe and terminates in the primary visual cortex, inferior to the calcarine sulcus (lingual gyrus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What area of the brain represents the macula?

A

Posteriorly, just lateral to the tip of the calcarine sulcus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where is the oculomotor nucleus located?

A

Dorsal midbrain at the level of the superior colliculus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the motor functions of the oculomotor nerve?

A

Ipsilateral innervation to IO, IR and MR

Contralateral innervation of the SR

Bilateral innervation of the LPS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where does CNIII exit the brainstem?

A

Through the interpeduncular fossa

Between the posterior cerebral and superior cerebellar artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

CNIII is susceptible to compression at what anatomical locations

A

Uncal herniation of the temporal lobe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What vascular structure does CNIII pass on its way out of the cranium

A

Lateral wall of the cavernous sinus superior to CNIV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

After CNIII passes the cavernous sinus, what happens to it?

A

Bifurcates into a superior and inferior branch at the anterior aspect of the sinus

27
Q

Where does CNIII exit the cranium?

A

Superior orbital fissure within the annulus of Zinn

28
Q

What branch of CNIII innervates the SR?

A

Superior branch

29
Q

What other muscle is innervated by the superior branch of CNIII?

A

Levator

30
Q

What muscles are innervated by the inferior branch of CNIII?

A

MR, IR, and IO

31
Q

What other neural fibres accompany CNIII?

A

Parasympathetic fibres originating from the Edinger-Westphal nuclei

32
Q

Where is the EW nucleus located?

A

In the midbrain, dorsal to the oculomotor nuclei

33
Q

What does the EW nucleus innervate?

A

Sphincter papillae and CB muscles

34
Q

Describe the afferent and efferent limbs of the pupillary reflex

A

Afferent (CNII)

Efferent (CNIII)

35
Q

Describe the pupillary light reflex in full

A

Fibres originate from retinal ganglion cells

Exit optic tract before reaching LGN to synapse on the ipsilateral pretectal nucleus

Pretectal nuclei project bilateral fibres to contralateral and ipsilateral EW nuclei

Preganglionic parasympathetic fibres from EWN travel w CNIII and exit from inferior branch of CNIII to synapse onto ciliary ganglion

Post-ganglionic fibres carried via short ciliary nerves to CB muscle and sphincter papillae

36
Q

What is accommodation?

A

Adaption of the eye when focussing on a near object

37
Q

How does accommodation work?

A

Increasing lens curvature (CB muscles contract via parasympathetics from EWN, leading to relaxation fo the zones)

Pupil contraction (sphincter activation from EWN)

Eye convergence (MR contraction from CNIII)

38
Q

Where is the nucleus of CNIV located?

A

Midbrain at the level of the inferior colliculus

39
Q

What does the trochlear nerve innervate?

A

Contralateral SO muscles

40
Q

Where does CNIV enter the SOF?

A

Above the common tendinous ring

41
Q

What are three defining characteristics of the trochlear nerve?

A

Only cranial nerve to exit dorsally from the brainstem.

Smallest cranial nerve in number of axons.

Longest unprotected intracranial course.

42
Q

Where is the abducens nucleus located?

A

Pontine tegmentum ventral to the fourth ventricle

Near the paramedial pontine reticular formation and surrounding fibres of CNVII

43
Q

Where does CNVI exit the brainstem?

A

At the pontomedullary junction and crosses over the apex of the petrous apex of the temporal bone

44
Q

There is a fibrous channel through the petrous apex of the temporal bone that transmits CNVI. What s it called and what is it s significance?

A

Dorello’s channel

Site of stretching of CNVI in the case of raised ICP

45
Q

Where does CNVI travel through the cavernous sinus in relation to the internal carotid artery?

A

Lateral to the ICA

46
Q

Where does CNVI enter the SOF?

A

Through the tendinous ring to innervate the LR

47
Q

What division of the nervous system is responsible for pupillary dilation?

A

Sympathetic

48
Q

What is Mullers muscle?

A

Smooth muscle in the upper eyelid, responsible for elevating the upper lid

49
Q

Describe the pathway for pupillary dilation?

A
  1. First order neutrons: start at the posterolateral hypothalamus and synapse at the interomediolateral cell column between C8 and T2 (ciliospinal centre of Budge)
  2. Second-order preganglionic neutrons leave the centre of Budge, travel over the lung apex and synapse at the superior cervical ganglion at the carotid bifurcation
  3. Third-order postganglionic neutrons travel around the ICA and innervate the dilator pupilae via long ciliary nerves (branches of the nasociliary n.)
50
Q

Where are voluntary/supranuclear eye movements initiated?

A

Frontal eye field (FEF), Brodmann area 8 in the frontal lobe

51
Q

Where are reflex eye movements initiated?

A

Occipital cortex and superior colliculus

52
Q

Supranuclear motor control consists of what three types of movements?

A
  1. Saccadic eye movements
  2. Smooth pursuit movements
  3. Vestibulo-ocular movements
53
Q

What are saccades?

A

Fast eye movements which involve the rapid fixation of a desired object onto the fovea with abrupt change of point fixation when switching from one object to the next.

54
Q

Describe the angular speed, duration and latency of saccades

A

Angular speed 600 degrees/s lasting around 30-100 milleseconds
after a latency of approximately 200ms

55
Q

Voluntary horizontal saccades are initiated by what part of the brain?

A

Frontal eye field

56
Q

Describe the route and destinations of projections from the FEF

A

Projections from the FEF go directly or via the superior colliculus to the contralateral paramedian pontine reticular formation (PPRF) which lies ventral to the abducens nerve

57
Q

What is the function fo the PPRF in the case of horizontal saccades?

A

Activates the ipsilateral abducens nucleus and sends impulses through the medial longitudinal fasciculus to activate contralateral oculomotor nucleus

58
Q

What part of the brain controls vertical saccades?

A

Rostral interstitial nucleus of the MLF (riMLF)

59
Q

What are smooth pursuit movements?

A

Refers to slow movements of the eye designed to keep a moving stimulus fixed at the fovea

60
Q

What is the latency of smooth pursuit?

A

100ms with much slower velocity than saccades

61
Q

Where is smooth pursuit initiated?

A

Parieto-occipital areas

62
Q

What are vestibule-ocular movements?

A

Eye movements which stabilise the eye relative to head movements

63
Q

How do vestibule-ocular movements work?

A

Sensory information from the semi-circular canals result in eye movements opposite to head movements

64
Q

What areas of the brain control vestibule-ocular movement?

A

Projections from the vestibular nuclei to cranial nerves and PPRF

Ophthalmology (7 decks)

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