Cranial nerves

Question 1

eye movements - muscles + nerves tested

Answer 1

medial - medial rectus (3):
+ up - inferior oblique (3)
+ down - superior oblique (4)

lateral - lateral rectus (6):
+ up - superior rectus (3)
+ down - inferior rectus (3)

Question 2

3rd (oculomotor) nerve palsy - presentation

Answer 2

eye deviated down and out
ptosis
dilated pupil

Question 3

3rd (oculomotor) nerve palsy - causes

Answer 3

diabetes - pupil oft spared
PCA aneurysm - oft painful
raised ICP - false localising sign

Question 4

ptosis - differentials + how do you determine them

Answer 4

normal pupil - myasthenia, partial 3N palsy
small pupil - horner’s
large pupil - complete 3N palsy

Question 5

6th (abducens) nerve palsy - presentation

Answer 5

failure of abduction (lateral rectus affected)

Question 6

6th (abducens) nerve palsy - causes

Answer 6

idiopathic
skull fracture
diabetes
tumour (nasopharyngeal)
demyelinating disease