Brainstem Lesions

Question 1

Hallmark sign of brainstem lesions

Answer 1

alternating syndromes

ipsilateral CN Sx

contralteral long tract Sx

Question 2

Rule of 4s

Answer 2

4 medial structures with “M”

4 lateral structures with “S”

4 CN locations

4 motor CN nuclei at midline, factors of 12

Question 3

4 medial brainstem structures

Answer 3

Motor pathway (corticospinal)

Medial lemniscus

Medial longitudinal fasciculus

Motor CN nuclei

Question 4

4 CN locations

Answer 4

4 in pons, 4 above , 4 below

pons: V, VI VII, VIII
forebrain: I, II
midbrain: III, IV
medulla: IX, X, XII
cord: XI

Question 5

4 motor nuclei in midline

Answer 5

all divide into 12

CN III

CN IV

CN VI

CN XII

Question 6

4 “side”/lateral lesions “S”

Answer 6

spinothalamic

sympathetic tract

sensory nucleus of CN V

spinocerebellar tract (ataxia of limbs)

Question 7

Spinocerebellar tract is located where

lesion causes what?

Answer 7

lateral brainstem

lesion: limb ataxia

Question 8

Medial longitudinal fasiculus

location?

lesion?

Answer 8

midline pons

lesion → ipsilateral internuclear opthalmoplegia