Trigeminal Pathways - 4/22 Stephens

Question 1

Both the sensory and motor roots of V pierce what structure just posterolateral to the pons?

Answer 1

Middle cerebellar peduncle

Question 2

Precise tactile information to the face travels via what nucleus?

Short/long fibers?
Ascend/descending root?

Answer 2

Main sensory nucleus of V

Short ascending

Question 3

1 half of primary fibers descend only in the descending root of V, where do they terminate?

What information do they convey?

Answer 3

Subnucleus caudalis of the descending nucleus of V

A delta pain and temp info from the face

Question 4

Where do secondary axons decussate and ascend in the pain/temp pathway from the face?

Where do the secondary axons terminate?

Answer 4

Trigeminal nucleus (TL)

ventral posterior medial (VPM) nucleus of dorsal thalamus

Question 5

Tertiary axons from the VPM nucleus terminate where?

Answer 5

Post central gyrus (head region of primary somesthetic cortex)

Question 6

C type pain fibers covey slow pain to where?

Neurons from this location project to where?

Answer 6

Subnucleus caudalis

RF

Question 7

Primary axons conveying crude tactile pathways from the face convey information to what nuclei?

Answer 7

Main sensory nucleus (ascending)

Subnuclei rostralis and interpolates of the descending nucleus (descending)

Question 8

Secondary axons from the crude tactile pathway will travel in what ways before reaching the VPM of the thalamus?

Answer 8

TL

dorsal central Trigeminal tract (DCTT) REMAIN UNCROSSED

Question 9

Precise tactile information from the face has a primary neuron that travels where?

Answer 9

Ascends ONLY in the short ascending root of V and terminates in the main sensory nucleus of V

Question 10

Secondary neurons of the precise tactile pathway from the face travel how?

To where?

Answer 10

Ipsilateral dorsal central Trigeminal tract (DCTT)
TL

VPM

Question 11

Tertiary neurons from the precise tactile pathway will end up where?

Answer 11

Postcentral gyrus of the primary somesthetic cortex

Question 12

Proprioception to the face travels via what nucleus?

Crosses how?

Then where?

Final spot?

Answer 12

Main sensory nucleus

DCTT and TL

VPM

primary somesthetic cortex

Question 13

Which nuclei project to the cerebellum?

Answer 13

Subnuclei rostralis

Interpolaris

Question 14

Precise tactile and proprioception from the head to the cerebellum must coarse through what nucleus and structure?

Answer 14

Main sensory nucleus of V

Superior cerebellar peduncle

Question 15

Unilateral lesion of the Trigeminal nerve results in what?

Answer 15

Loss of sensation in Trigeminal dermatomes
Loss of jaw jerk reflex
Atrophy of muscles of mastication
Loss of ipsilateral and consensual corneal reflex

Question 16

Alternating analgesia is due to destruction of what?

Patients demonstrate what?

Answer 16

Primary fibers in descending tract of V
Secondary fibers in the SL

Ipsilateral hemianalgesia of the face
Contralateral hemianalgesia of the body

Question 17

Alternating Trigeminal hemiplegia is a result of what?

Results in what?

Answer 17

Unilateral destruction of the Trigeminal nerve and corticospinal tract (SL) in the pons

Ipsilateral Trigeminal anesthesia and paralysis
Contralateral spastic hemiplegia

Question 18

What is the only pseudounipolar neuron in the CNS?

Answer 18

Mesencephalic nucleus of CN V