Midbrain

Question 1

contains which CN?

Answer 1

IV, III

Question 2

GSE (IV)

Answer 2

trochlear nucleus to contralateral superior oblique

Question 3

trochlear nucleus lesion

Answer 3

rare, contralateral SO affected, possibly with Horner’s

Question 4

trochlear nerve lesion

Answer 4

before decussation (rare): contralateral SO at decussation: bilateral SO’s after decussation: ipsilateral SO

Question 5

signs of trochlear lesion

Answer 5

extorsion (inability to look down and in); vertical diplopia (seen when reading or walking down stairs); head tilted, and chin down contralateral to affected SO (reduces diplopia),

Question 6

causes of trochlear lesion

Answer 6

hemmorhage, infarct, hydrocephalus, trauma

Question 7

GSE (III)

Answer 7

oculomotor nucleus to levator palpebrae superioris and extrinsic eye muscles

Question 8

GVE (III)

Answer 8

nucleus of Edinger-Westphal to ciliary ganglion (to pupillary constrictor and ciliary body)

Question 9

oculomotor palsy

Answer 9

causes eye to look down and out; mydriasis (dilation); full ptosis

Question 10

posterior commissure

Answer 10

pupillary light reflexes

Question 11

periaqueductal grey

Answer 11

pain

Question 12

red nucleus

Answer 12

motor system

Question 13

substantia nigra

Answer 13

production of dopamine; motor system

Question 14

ventral tegmental area

Answer 14

dopamine production; limbic system

Question 15

lateral leminiscus

Answer 15

hearing