Nerve palsies and visual fields

Question 1

what muscle is affected in a 6th nerve (abducent) palsy

Answer 1

lateral rectus

Question 2

symptoms of a 6th nerve palsy

Answer 2

cannot abduct the eye

horizontal diplopia

Question 3

causes of 6th nerve palsy

Answer 3

microvascular
^ ICP (impinges nerve of petrous tip)
tumour
congenital

Question 4

signs of 6th nerve palsy

Answer 4

swollen optic disc from ^ICP
headaches
unable to abduct eye

Question 5

What muscle is affected in a 4th nerve (trochlear) palsy

Answer 5

superior oblique

Question 6

symptoms of a 4th nerve palsy

Answer 6

vertical diplopia
cannot intort or depress
eye seems to be looking up

Question 7

causes of a 4th nerve palsy

Answer 7

congenital
microvascular
tumour

Question 8

trochlear nerve is the longest CN and the only one to come out of the posterior brainstem, true or false

Answer 8

true

Question 9

signs of a 4th nerve palsy

Answer 9

eye seems to be looking up because unopposed from other muscles
compensate with a head tilt

Question 10

what muscles are affected in a 3rd nerve (oculomotor) palsy

Answer 10

superior rectus 
inferior rectus 
medial rectus 
inferior oblique 
levator palpebrae superioris 
sphincter pupillae muscle

Question 11

causes of a 3rd nerve palsy

Answer 11

microvascular 
tumour 
aneurysm 
demyelination 
congenital

Question 12

symptoms and signs of a 3rd nerve palsy

Answer 12

down and out eye position from unopposed SO muscle
ptosis from LPS
dilated pupil from sphincter pupillae muscle
absent accommodation reflex

Question 13

what is a cause of a painful 3rd nerve palsy

Answer 13

aneurysm

Question 14

main cause of a 3rd nerve palsy

Answer 14

aneurysm

Question 15

main cause of a 4th nerve palsy

Answer 15

congenital

trauma

Question 16

main cause of a 6th nerve palsy

Answer 16

^ ICP

Question 17

what is inter nuclear opthalmoplegia (INO)

Answer 17

sign seen as a result of a problem in the medial longitudinal fasciculus (MLF) which connects the CN3 nucleus in the midbrain and CN6 nucleus in pons

• ipsilateral adduction impaired
• contralateral abduction shows horizontal nystagmus

Question 18

Causes of INO

Answer 18

MS
stroke
vascular

Question 19

causes of damage to optic nerve resulting in nasal and temporal loss of visual field

Answer 19

ischaemic optic neuropathy

optic neuritis

Question 20

a defect in which location would result in a bitemporal hemianopia

Answer 20

optic chiasm

Question 21

causes of bitemporal hemianopia

Answer 21

pituitary adenoma

craniopharyngeoma

Question 22

a defect in which location would result in a homonoymous hemianopia

Answer 22

optic tract

Question 23

causes of homonymous hemianopia

Answer 23

stroke
demyelination
tumour

Question 24

is there macular sparing in damage to the optic tract

Answer 24

no

Question 25

temporal optic radiations carry signals from the inferior/superior retina corresponding to superior/inferior visual fields

Answer 25

temporal radiations:
inferior retina
superior visual field

Question 26

parietal optic radiations carry signals from the inferior/superior retina corresponding to superior/inferior visual fields

Answer 26

parietal radiations:
superior retina
inferior visual field

Question 27

a defect in which location would result in a superior quadrantoptropia

Answer 27

temporal branches of the optic radiations

inferior retina –> superior visual field

Question 28

a defect in which location would result in an inferior quadrantoptropia

Answer 28

parietal branches of the optic radiations

superior retina –> inferior visual field

Question 29

a defect in which location would result in homonymous hemianopia WITH macular sparing

Answer 29

occipital visual cortex