Trigeminal Nerve System

Question 1

Where do sensory signals from the body come from?

Answer 1

• posterior column-medial lemniscal pathway
• spina-cerebellar pathways
• anteriolateral system

Question 2

Where do sensory signals for head come from

Answer 2

Trigeminothalamic pathways

-trigeminocerebellar pathways

Question 3

The sensory system that detects and transmits signals from the face no anterior scalp

Answer 3

Trigeminal nerve

Question 4

What are some types of sensations of trigeminal nerve

Answer 4

• fine touch
• flutter-vibration
• proprioception (position sense)
• temperature sensation
• nociception (pain)
• visceral sensation from the oral cavity

Question 5

Trigeminal nerve also provides touch and pain sensation to

Answer 5

• supratentorial dura mater

- the nasal sinuses, nasal cavity, mouth, and anterior two-thirds of the tongue

Question 6

Where does the trigeminal nerve exit the brainstem

Answer 6

Midpontine level

Question 7

After the trigeminal nerve crosses the subarachnoid space, what does it enter

Answer 7

A fossa posterior and inferolateral to the cavernous sinus called meckel’s cave

Question 8

What lies in Meckel’s cave

Answer 8

Trigeminal ganglion

Question 9

Where does V1 exit the skull

Answer 9

Superior orbital fissure

Question 10

Where does V2 exi the skull

Answer 10

Foramen rotundum

Question 11

Where does V3 exit skull

Answer 11

Forman ovale

Question 12

Where are the cell bodies of the trigeminal PRIMARY afferent neurons located

Answer 12

In he trigeminal ganglion

Question 13

What are the sensory nuclei for the trigeminal nerve

Answer 13

• principal sensory nucleus

- spinal nucleus

Question 14

What is the motor nucleus for trigeminal nerve

Answer 14

Motor trigeminal nucleus (muscles of mastication)

Question 15

Where do part of the primary sensory neurons synapse?

Answer 15

Principal sensory nucleus, some in the spinal nucleus (descending branches)

Question 16

The relay and central processing of input from trigeminal first order neurons occurs in the ________ nuclei

Answer 16

Brainstem

Question 17

Second order neurons cross the midline forming the

Answer 17

Anterior trigeminothalamic tract

Question 18

Where do the second order neurons that cross the midline and form the anterior trigeminothalamic tract communicate with third order neurons

Answer 18

In the contralateral thalamus

Question 19

Within the brainstem, the ascending branches of trigeminal terminate in the ______________ located in the pons

Answer 19

Principal sensory nucleus

Question 20

What do the fibers that terminate in the principal sensory nucleus carry?

Answer 20

• fine touch
• position
• vibration

Question 21

The descending branches of the trigeminal nerve coalesce to form the ____________ of the trigeminal nerve

Answer 21

Spinal (descending) tract

Question 22

What kind of fibers do the descending branches that terminate in the spinal trigeminal nucleus carry?

Answer 22

• pain

- temperature

Question 23

What happens if there is a lesion on the spinal trigeminal nucleus?

Answer 23

Lesion here will spare fine touch

Question 24

Neurons in the ventrolateral part of the principal sensory nucleus give rise to axons that project to the what

Answer 24

Contralateral ventral posteromedial nucleus of the thalamus

Question 25

The ascending projections from the principal sensory nucleus form what

Answer 25

Anterior trigeminothalamic tract, which courses close to the medial lemniscus

Question 26

What do the neurons in the principal sensory nucleus relay?

Answer 26

Discimitive tactile info from the head to the (VPM) of the thalamus

Question 27

The third order neurons of the trigeminal nerve project from the VPM through the posterior limb of the internal capsule and do what

Answer 27

Reach the sensory cortex

Question 28

What forms the anterior trigeminothalamic tract

Answer 28

The axons of the second order neurons in the spinal trigeminal nucleus decussate, then coalesce to form this

Question 29

Where do the fibers of the trigeminothalamic tract terminate

Answer 29

In the ventral posterio-medial (VPM), the posterior, and the intralaminar nuclei of the thalamus

Question 30

What do the fibers of the trigeminothalmic tract carry

Answer 30

Pain and temp

Question 31

The third order neurons from the trigeminothalamic tract project from the VPM through the posterior limb of the internal capsule and reach what

Answer 31

Sensory cortex

Question 32

Unilateral lesion at the spinal trigeminal tract/nucleus but sparing the main nucleus

Answer 32

Lost: pain and temp ipsilateral Spared: fine touch and position

Question 33

Lesion of the lateral pons or medulla-pons border damaging all the main sensory, motor nucleus, and the ascending TTT from the medulla

Answer 33

Lost: pain and temp contralterally Lost: fine touch and position ipsilateral lay Paralysis of the muscles of mastication

Question 34

Lesion rostral to all the nuclei that damages the TTT

Answer 34

Lost: pain and temp Lost: fine touch and position

Question 35

How are the spinal trigeminal tract and nucleus organized

Answer 35

Somatotopically - V1 more localized more centrally - V2 in the middle - V3 dorsally

Question 36

Perioral areas are represented where

Answer 36

More rostrally in then nucleus

Question 37

PICA stroke

Answer 37

Affects lateral medulla - sensory loss for pain and temp from ipsilateral face - if only the lower part of spinal nucleus is affected, the sensory loss will be around mouth - if only the upper part of the spinal nucleus is affected, the sensory loss will be as a mantle around the face

Question 38

Some of the neurons of the trigeminal nerve reside in the ____________ if they are not in the trigeminal nucleus

Answer 38

Mesencephalic nucleus

Question 39

The central processes of the trigeminal mesencephalic neurons innervate what

Answer 39

Cells of the trigeminal motor nucleus

Question 40

Trigeminal motor neurons project through V3 and innervate

Answer 40

Muscles of mastication

Question 41

Sensory neurons located in the mesencephalic nucleus that contact with motor neurons in the motor nucleus do what

Answer 41

Form a reflex loop

Question 42

The input from trigeminal mesencephalic nucleus sensory neurons to the motor nucleus forms the

Answer 42

Afferent limb of the myotatic jaw jerk reflex

Question 43

The jaw jerk reflex consists of sensory neurons that innervate _____________ and terminate on _________

Answer 43

Muscle spindles in jaw closing muscles Trigeminal motor neurons

Question 44

In jaw jerk reflex the axons of the trigeminal motor neurons innervate

Answer 44

Muscles that elevate jaw

Question 45

What does a gentle tap on the jaw activate

Answer 45

The afferent fibers of the jaw jerk reflex and initiates a contraction of the homonymous muscle as we its synergists

Question 46

What does the jaw jerk proved reflex for

Answer 46

To jaw muscles during mastication to regulate bite force

Question 47

What do the primary neurons from CNV serve

Answer 47

Cutaneous sensation from face, temporal region, and the anterior scalp

Question 48

The trigeminal also innervates

Answer 48

- supratentorial meninges - temporomandibualr joint - oral cavity, tooth pulp, and periodontium

Question 49

The peripheral distribution of the branches of the CNV delineate what

Answer 49

The facial dermatomes

Question 50

Boundaries of the facial dermatomes

Answer 50

Sharply defined

Question 51

What helps sharpen the contrast between adjacent receptive fields in the facial dermatomes

Answer 51

Second order neurons in the principal sensory nucleus have relatively small receptive fields

Question 52

How to test CNV

Answer 52

- pt clsoe eyes - use sharp object to test pain or soft object to test fine touch - test each side of the face at the levels of the nerve - ask patient to point where they felt the touch

Question 53

What is a clinical condition that illustrates the divisional pattern of the trigeminal system

Answer 53

Herpes zoster or shingles

Question 54

Rash from shingles

Answer 54

Outlines the affected dermatome or spinal cord segment. V1 or V2 is usually affected, and the rash is unilateral. Cornea may be affected and could lead to blindness

Question 55

This type of headache is from hypertension. Feels like the head is being squeezed

Answer 55

Tension headache

Question 56

This type of headache is usually mostly one sided accompanied by vertigo, nausea, photophobia

Answer 56

Migraine

Question 57

This type of headache more common in men, above hte eye (red eyes). Very intense

Answer 57

Cluster headache

Question 58

This type of headache is extremely intense pain. Can originate from anywhere, very sharp. Can be neuropathic or symptom of CNV compression. Imaging would be needed

Answer 58

Trigeminal neuralgia

Question 59

Headache connected to trigeminal nerve

Answer 59

Meninges are supplied by fibers of the trigeminal ganglion cells that terminate in the spinal trigeminal nucleus. These fibers are though to be involved in the pain of migraine headaches

Question 60

Described as one of the most painful conditions known

Answer 60

Trigeminal neuralgia

Question 61

Principal sensory nucleus

Answer 61

Transmits fine touch

Question 62

Spinal nucleus

Answer 62

Transmits pain and temp

Question 63

Mesencephalic nucleus

Answer 63

Forms reflex loop

Question 64

Motor nucleus

Answer 64

Sends motor neurons via V3 to innervate the muscles of mastication

Question 65

What forms the anterior trigeminothalamic tract

Answer 65

Second order neurons crossing the midline

Question 66

What do third order neuron of trigeminal do

Answer 66

Project through the posterior limb of the internal capsule and reach the sensory cortex