11_Neuro 2.6 Sensation From The Face: The Trigeminal Sensory System

Front 1

What are the DRG homologues of the face?

Back 1

Trigeminal ganglia

Front 2

What is the sensory nucleus called for the Trigeminal fine touch system and where is it located?

Back 2

It is called the main (AKA chief) sensory nucleus and it is located in the pons.

Front 3

What is the sensory nucleus for the trigeminal pain and temp system called and where is it located?

Back 3

It's called the spinal trigeminal nucleus; it is a long column-like nucleus extending from the pons down to the cervical spinal cord.

Front 4

Describe the path of the fine touch neurons in the MAJOR pathway for trigeminal.

Back 4

1. MechanoR to CHIEF (or main) SENSORY NUCLEUS OF V in the PONS on ipsi side.
2. 2nd order neurons then send off fibers that cross to the other side of the pons and form the TRIGEMINAL LEMNISCUS (which joins the MEDIAL LEMNISCUS)
3. The trigeminal lemniscus ascends to the Ventral Posterior Medial (VPM) nucleus of the thalamus and terminates on 3rd order thalamic neurons

Front 5

Describe the somatotopy of the tongue and face in the VPM

Back 5

Tongue = Medial
Face = Lateral

Front 6

Describe the minor pathway for some crude touch:

Back 6

1. A few mechanoR enter the pons
2. Descend directly in the spinal tract of V to spinal nucleus of V where they synapse
3. 2nd order neurons then send fibers that cross the midline and ascend in the trigeminothalamic tract to VPM.

Front 7

Describe the minor pathway for oral cavity:

Back 7

1. A few mechanoR enter the pons and synapse in Chief Sensory nucleus
2. 2nd order neurons don't cross but ascend on ipsi side to ipsi VPM
3. Conveys touch and pressure sensation from oral cavity, including teeth, mouth and gums.

Front 8

Somatic neurons of the face and body enter tracts at different levels of the brainstem - however they ultimately run together before reaching the cortex. Where does each enter and where do then run together? What is this tract called?

Back 8

1. Body fibers enter Medulla
2. Face fiber enter Pons
3. The run together Rostral to the pons in the Medial/Trigeminal lemniscus tracts.

Front 9

Describe the path of the trigeminal pain and temp pathway:

Back 9

1. Nociceptors from face enter nerve V at pons
2. They do not synapse but descend ipsi in the spinal trigeminal tract and terminate in the spinal trigeminal nucleus of V
3. 2nd order neurons send axons that cross to other side of medulla.
4. Then they ascend as the trigeminothalamic tract along side the anterolateral tracts to the VPM.
5. 3rd order neurons in VPM project through the posterior limb of the internal capsule and corona radiata up to the lateral SI cortex. Others project to the reticular formation.

Front 10

Tic Douloureux typically occurs in which nerve fibers? What is the treatment and how does it work?

Back 10

CNV2 and CNV3. Carbamazepine is anti convulsant that acts on Na channels and reduces excitability of neurons.

Front 11

What where is the pain in TMJD? What is the treatment?

Back 11

It is at the Maxilla and Mandibular joint. NSAIDS and stress management.