Exam 2 week 6 ppt 3 CN 5 Trigeminal Nerve Flashcards
what is the number for the Trigeminal nerve?
V
name the functional categories of the trigeminal nerve
General sensory (head and face)
- –Opthalmic (V1)
- –Maxillary (V2)
- –Mandibular (V3)
Motor (muscles of mastication)
- Mandibular (V3) division
Another name for the Spinal trigeminal nucleus
nucleus of the spinal tract of V
what are the three division of the trigeminal nerve?
- –Opthalmic (V1)
- sensory
- –Maxillary (V2)
- sensory
- –Mandibular (V3)
- sensory
- motor
what is the only division of the trigeminal nerve that contains motor function?
Mandibular (V3)
What does the Ophthalmic nerve pass through when entering the scull?
Superior Orbital fissure
What does the maxillary nerve pass through when entering the scull?
foramen rotundum
What does the Mandibular nerve pass through when entering the scull?
foramen ovale
Does the trigeminal nerve have high or low innervation density?
What does the Ophthalmic nerve pass through when entering the scull?
another name for the spinal tract of V
spinal trigeminal nucleus
For the three sensory divisions of the trigeminal nerve, where are the primary afferent cell bodies found?
and what is it equivilant to?
–Primary afferent cell bodies in in the trigeminal ganglion
(equivalent to DRG)
where are the 2nd degree neurons for the sensory divisions of the trigeminal nerve? (3)
- Spinal trigeminal nucleus – (nucleus of the spinal tract of V)
- Chief (main) sensory nucleus
- Mesencephalic trigeminal nucleus
what is the difference between nociception and pain?
Physiologists distinguish between pain and nociception; where
- nociception refers to signals arriving in the central nervous system resulting from activation of specialized sensory receptors called nociceptors that provide information about tissue damage.
- Pain then is the unpleasant emotional experience that usually accompanies nociception.
http://cell.uchc.edu/pdf/fein/nociceptors_fein_2012.pdf
how many regions does the spinal trigeminal nucleus have?
three
§Oralis
§Interpolaris
§Caudalis
what are the three regions of the nucleus of the spinal tract of V?
(the nucleus of the spinal tract of V = spinal trigeminal nucleus)
- Oralis
- Interpolaris
- Caudalis
Nucleus oralis:
location
transmits
one of three regions of spinal trigeminal nucleus
- Most rostral
- Transmits
- fine (discriminative) orofacial touch
Nucleus interpolaris:
location
transmits
one of three regions of spinal trigeminal nucleus
- Mddle position
- Transmits
- Non-discriminative (crude) touch
- dental pain
nucleus caudalis:
location
Transmits
one of three regions of spinal trigeminal nucleus
- Most caudal
- transmits:
- orofacial nociception
- thermal sensations
what is the spinal trigeminal tract?
first degree afferent axons from CN V that go either ascending or descending to 2nd degree neurons in the: nucleus of the spinal tract of V (spinal trigeminal nucleus)
(the words under Dr. Lake’s powerpoint says it could be to the mesencephalic trigeminal nucleus, or the cheif trigeminal nucleus too, but that is not what other sources say. I also emailed Dr. Lake and he replied that it is just the spinal trigeminal nucleus!)
bunnies and kitty!
cheif sensory nucleus
what does it do?
Chief Sensory Nucleus receives and relays Fine (discriminative) orofacial touch sensations
Mesencephalic nucleus
location
what cell bodies are in it & purpose of those neurons?
in the midbrain and rostral pons
contains first degree afferent cell bodies for proprioceptive informatinon from the muscles of mastication - jaw position
(these primary afferents are the only CN V afferents that do not have their cell bodies in the trigeminal ganglion. This nucleus gives rise to our sensation of jaw position and is the afferent limb in reflexes like the jaw jerk reflex.)
what primary afferents ore the only CN V afferents that do not have their cell bodies in the trigeminal ganglion?
the 1° afferent cell bodies for proprioceptive information from muscles of mastication.
they synapse in the Mesencephalic Nucleus of the midbrain and rostral pons
what nucleus gives rise to our sensation of jaw poistion and is the afferent limb in reflexes like the jaw jerk reflex?
Mesencephalic Nucleus of the midbain and rostral pons
The Motor nucleus of V
location
contains
The Motor nucleus of V is
- Located in mid-pons just medial to the primary sensory nucleus of V and
- contains LMN to muscles of mastication & tensor tympani
what is true about the three ascending tracts of the Trigeminal nerve?
All are decussated secondary axons from trigeminal relay nuclei
name the three ascending tracts of teh trigeminal nerve
- –Lemniscal tract
- –Thalamic tract
- –Paramedial tract
Ascending V lemniscal pathway (tract):
origin
becomes
From the Chief sensory & nucleus oralis
Becomes the head region of the medial lemniscal tract
Ascending V thalamic pathway
Origin
becomes
–From nucleus interpolaris & nucleus caudalis
–Becomes the head region of the antero-lateral tracts
Which systems (I think this means pathways) project to the Ventral Posteromedial nucleus of the thalamus (VPM)
Powerpoint said “both systems” after describing the medial lemniscal tract and the anterolateral tracts, so I think it is the following
- Medial lemniscus system
- Anterolateral System
What are in the Ventral Posteromedial nucleus of the thalamus?
3rd degree neurons of pathway that include the
- ascending V thalamic pahtway and
- ascending V lemniscal pathway
Where does the asending V thalamic pathway synapse with 3rd degree neurons? (after becoming the head region of the anterolateral tracts)
Where do the 3rd degree neurons project?
synapse in Ventral Posteromedial thalamus (VPM)
projets onto face region along lateral somatosensory cortex
Where does the asending V lemniscal pathway synapse with 3rd degree neurons? (after becoming the head region of the medial lemniscal tract)
Where do the 3rd degree neurons project?
synapse in Ventral Posteromedial thalamus (VPM)
projets onto face region along lateral somatosensory cortex
Trigeminal nerve V: ascending tracts: The paramedial ascending system involves projcetctions
from where?
to where?
function
Projections from:
- chief sensory and
- spinal trigeminal nuclei
projcetions to:
- midline thalamus &
- into limbic system.
projections represent the Emotional response to facial touch or pain
Four ways to clinically evaluate the Trigeminal Nerve:
- Corneal reflex
- Jaw Jerk reflex
- Sensory tests for fine touch and pin prick to the face
- Palpate usles of mastication, (have pt resist jaw opening during palpation)
How do you test corneal reflex?
what is the afferent and efferent limbs?
- Touch cornea with wisp of cotton
- normal: produces blinking of the eye with V
- V is afferent limb & VII is the efferent limb
how does a jaw jerk reflex test work?
what are the afferent & efferent limbs?
what nuclei are invovled in the reflex?
- tapping of the jaw produces reflex contraction of the muscles of mastication
- –Afferent & efferent limb mandibular V3
- –Both thru mesencephalic & motor nucleus of V
sensory test for fine touch and pin prick to face
will be discussed later with somatosensory systems
what muscles should we palpate in clinical evaluation of the trigeminal nerve & locations?
what should we do while palpating?
–Masseter (A)
–Temporalis (B)
–Pterygoid (C)
have pt resist jaw opening during palpation
what is the most common disorder of CN V?
Trigeminal Neuralgia (tic douloureux)
Trigeminal Neuralgia (tic douloureux)
what is it?
what happens?
cause
)Most common disorder of CN V)
- Disease of PNS affecting the trigeminal ganglion or nerve
- No motor or sensory losses
- Excruciating bursts of pain, usually in one of the three sensory distributions of CN V
- No known cause but often triggered by use of jaw, yawning, hot and cold, light breeze on face
Lets talk about lesions to the trigeminal nerve. First Trigeminal Neuralgia (tic douloureux) is the Most common disorder of the trigeminal nerve. It is a condition of the PNS affecting the trigeminal ganglion or nerve. It involves Excruciating bursts of pain, usually in one of the three sensory distributions of CN V but with No motor or sensory losses. There is No known cause but often triggered by use of jaw, yawning, hot and cold, light breeze on face
Herpes Zoster Ophthalmicus
prevalance
what happens?
another lesion of the Trigeminal nerve
- 10-15% of all cases of herpes zoster
- Inflammatory and infectious disease
- 2–3 days of severe pain along distribution of the opthalmic division (V1) of CN V
- Rash follows in this distribution
- Can result in permanent corneal damage
Herpes Zoster Ophthalmicus occurs in 10-15% of all cases of herpes zoster. It is a viral infectious disease accompanied by Inflammatory response around the nerve. It generally has the following symptoms 2–3 days of severe pain along distribution of the opthalmic division (V1) of CN V, Rash follows in this distribution and it can result in permanent corneal damage
Wallenberg’s syndrome
what is another name for it?
what causes it?
what charecterizes it?
- •Also called lateral medullary syndrome
- •Typically caused by a vascular lesion, occlusion of the posterior inferior cerebellar artery (PICA)
- •Characterized by loss of pain and thermal sense in ipsilateral face and contralateral body due to damage of ascending spinal trigeminal and STT tracts
Wallenberg’s Syndrome is a vascular condition also called lateral medullary syndrome. It is Typically caused by a vascular lesion, specifically occlusion of the posterior inferior cerebellar artery (PICA). Wallenberg’s Syndrome is Characterized by loss of pain and thermal sense in ipsilateral face and contralateral body due to damage of ascending spinal trigeminal axons and spinothalamic tracts because it affects the ascending Spinothalamic tracts that have already decussated and the spinal tract of V which carries axons which have not yet decussated
What provides cortical control of the msucles of mastication?
the descending corticobulbar fibers
(this will be discussed more in the future)
