Brainstem Review

Question 1

Midbrain diagram

Answer 1

Question 2

Pathway of visual information involved in light reflexes

Answer 2

Question 3

Sympathetic pathway for pupillary dilation (diagram)

Answer 3

1. First-order neurons travel from the hypothalamus through the brainstem to the intermediolateral column (ciliospinal center of Budge).
2. Second-order (preganglionic) neurons travel from the spinal cord over the lung apex to the superior cervical ganglion.
3. Third-order (postganglionic) neurons travel from the superior cervical ganglion to the eye, traveling alongside the internal carotid artery in the neck and cavernous sinus.

Question 4

Brainstem CN nuclei diagram

Answer 4

Question 5

Brainstem CN nuclei diagram with axial cross-sections

Answer 5

Question 6

Lateral medullary syndrome summary

Answer 6

Question 7

Ventral pontine syndrome summary

Answer 7

Question 8

Ventral midbrain syndrome summary

Answer 8

Question 9

Medial medullary syndrome

Answer 9

Question 10

Levels of cerebellar peduncles

Answer 10

Question 11

Midbrain vascular supply

Answer 11

Question 12

Rostral Pons vascular supply

Answer 12

Question 13

Cerebellar peduncle summary

Answer 13

Question 14

Caudal Pons vascular supply

Answer 14

Question 15

Medulla vascular supply

Answer 15

Question 16

Corticospinal tract at all layers of spine and brainstem

Answer 16

Question 17

Anterolateral tract at all layers of spine and brainstem

Answer 17

Question 18

Dorsal column tract/medial lemniscus at all layers of spine and brainstem

Answer 18

Question 19

Identify the important midbrain regions

Answer 19

• Anterolateral tract also in green on original diagram
• Note that the trochlear nerve nucleus is just below this level in the same location as the occulomotor nucleus, but its nerve fibers decussate and exit posteriorly rather than staying ipsilateral and exiting anteriorly as the occulomotor nerve does.

Question 20

Identify the important pontine structures

Answer 20

Question 21

Major nerves entering/exiting the medulla

Answer 21

Question 22

Identify the important medullary structures

Answer 22

Question 30

Reflexes to test at each brainstem level

Answer 30

• Medulla: Gag reflex
• Pons: Corneal reflex
• Midbrain: Pupillary reflex

Question 31

The Rule of Fours

Answer 31

1. There are 4 structures in the midline that begin with M:
   
   1. The Motor pathway (corticospinal tract)
   2. The Medial lemniscus
   3. The Medial longitudal fasciculus
   4. The Motor nerve nuclei
2. There are 4 structures on the side that begin with S:
   
   1. The Spinocerebellar pathway
   2. The Spinothalamic pathway
   3. The Sensory nucleus of 5
   4. The Sympathetic pathway
3. There are 4 cranial nerves each in the midbrain, medulla, and above the pons
4. The 4 motor nuclei that are in the midline are those that divide equally into 12 except for 1 and 2
   
   1. That is 3, 4, 6, and 12