2 CN5 Flashcards
what are the 3 branches of trigeminal nerve and their entrance to the cranium?
1) ophthalmic (V1)= superior orbital fissure
2) Maxillary (V2)= Pterygopalatine fossa via foramen rotundum
3) Mandibular (V3)= passes through foramen ovale to the infraorbital fossa
what is the only division of CN5 to contain motor fibers?
Mandibular V3
** CN5 is mixed (both sensory and motor)
V1
ophthalmic
superior orbital fissure
V2
maxillary
pterygopalatine fosse via foramen rotundum
V3
mandiular
foramn ovale to infraorbital fossa
what branch of CN5 is ONLY motor?
V3 mandibular
SVE are what nerves?
5,7, 9, 10, 11
Sensory dermatome fibers of V1?
- Tip of nose**
- Along top of nose
- Upper eyelids
- Forehead and along majority of parietal bone region
Sensory dermatome fibers of V2?
- Upper lip
- Sides of nose
- Lower eyelid
Sensory dermatome fibers of V3?
- Anterior tongue
- Bottom lip
- Along jaw and up side of face in anterior to ear
What branch of CN5 is largest?
- V3 is largest! Each branch gets larger as the number of myelinated axons increases
- Reminder: this is represented in homunculus (which depicts the proportions of nerves for bodily regions
- V1 > V2 > V3
What are the 3 main neural tracts on CN5?
1) Principal CN5 sensory nucleus
2) Spinal trigeminal nucleus
3) Mesencephalic nucleus of CN5
Principal CN5 sensory nucleus pathway
- 1st neuron cell body in CN5 ganglia
- Projects to ipsilateral principle nucleus to synapse on 2nd neuron there
- 2nd neuron axon decussates
- 2nd ascends as TRIGEMINAL LEMNISCUS to the thalamus
- At the thalamus, the 2nd neuron synapses on 3rd
- 3rd neuron axon travels to ‘face’ region of primary somatosensory cortex of post-central gyrus (lateral area)
Spinal trigeminal nucleus pathway
i. 1st neuron cell body in CN5 ganglia
ii. Projects to ipsilateral spinal nucleus to synapse on 2nd neuron there
1. Sometotopically arranged
iii. 2nd neuron axon decussates
iv. 2nd ascends as TRIGEMINOTHALAMIC TRACT to the thalamus
v. At the thalamus, the 2nd neuron synapses on 3rd
vi. 3rd neuron axon travels to ‘face’ region of primary somatosensory cortex of post-central gyrus (lateral area)
Mesencephalic nucleus of CN5 pathway
i. 1st neuron cell body IN THE NUCLEUS ITSELF
1. NOT IN TRIGEMINAL GANGLIA like other tracts
ii. 1st neuron could stop in nucleus
iii. 1st
iv. 2nd neuron axon decussates
v. 2nd ascends as TRIGEMINOTHALAMIC TRACT to the thalamus
vi. At the thalamus, the 2nd neuron synapses on 3rd
vii. 3rd neuron axon travels to ‘face’ region of primary somatosensory cortex of post-central gyrus (lateral area)