trigeminal sensory system

Question 1

Touch vibration proprioception pathway

Answer 1

1st neuron cell body: trigeminal ganglion
1st neuron central process: central trigeminal nerve fibers

2nd neuron cell bodies: principle/ chief/ main sensory nucleus
2nd neuron fiber tract: either trigeminal lemniscus (ventral trigeminothalamic tract) or dorsal trigeminothalamic tract (from oral cavity and uncrossed fibers)

3rd neuron cell bodies: VPM
3rd neuron fiber tract: internal capsule to S1 cortex

Question 2

Pain and temp pathway

Answer 2

1st neuron cell bodies: trigeminal ganglion
1st neuron central processes: Spinal Tract of V

2nd neuron cell bodies: spinal nucleus of V
2nd neuron fiber tract: Trigeminothalamic tract (ventral)

3rd neuron cell bodies: VPM
3rd neuron fiber tract: internal capsule to somatosensory cortex

Question 3

Trigeminal lemniscus (Ventral trigeminothalamic tract

Answer 3

2nd neuron, ascends from principle sensory nucleus of V to contralateral VPM carries lt, vib, prop information from the face
Runs along the medial lemniscus

Question 4

Spinal tract of V

Answer 4

1 sensory fibers, Descends from trigeminal gangion to ipsilateral nucleus of V, carries pain and temp sensation and crude touch from the face, analougous to lissauers tract in the spinothalamic path

Question 5

Trigeminal sensory nuclei

Answer 5

Main/chief/principle nucleus: located in lateral pons, fine touch and pressure from face and teeth

Spinal trigeminal nucleus: located in lateral pons, medulla and cervical sp cd, crude touch paina nd temp

Mesencephalic nucleus (Mechanoreceptors, Mastication)
Psuedounipolar neurons located in the midbrain along the lateral edge of the PAG, proprioception from muscles of mastication  (muscle spindles) and mechanoreceptors in the gums, teeth, and hard palate, central processes may project to trigeminal motor nucleus to facilitate jaw-jerk reflex

Question 6

Dorsal to Ventral somatotopy to spinal trigeminal nucleus

Answer 6

Mandibular- dorsal
Maxillary - middle
Ophthalmic- ventral

Question 7

rostral to caudal somatotopy in spinal trigeminal nucleus

Answer 7

pain and temperature fiber from… perioral regions are more rostral, occipital regions are more caudal

Central lesion of spinal trigeminal nucleus lead to deficits distributed along concentric rings

Question 8

Lateral sp cd lesion

Answer 8

body- ipsilateral lt vib and position

body- pain, temp pathway contralateral

Question 9

Lateral lesion of pons or medulla, lateral medullary syndrome

Answer 9

body- contralateral pain and temp

face- pain and temp lesion