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)
Describe motor tracts
- Corticobulbar
o Motor cortex projection down thru internal capsule
o Thalamus
o Down to lower motor units that reside within CN nucli
CN5 input to muscle
Are autonomics carried by CN5?
- BOTH autonomics and special afferents (taste) will be carried by NC5,
- These fibers are acquired; they are NOT resident fibers
Explain pre-synaptic and post synaptic for para and sym
- pre-synaptic para… cell bodies reside in IML and their axons ascend to synapse on superior, middle, and inferior ganglia in neck= 3 7 9 10
- post-synaptic para… hitch a ride on anything (blood, lymph, nerve -including CN5)
Principal CN5 sensory nucleus is sense for
a. Fine touch, dental pressure
b. GSA
c. Called trigeminal lemnicus
d. cheif sensory (DCML)
Spinal trigeminal nucleus sense for?
a. Crude touch, pain, temperature
b. GSA
c. Called trigeminothalamic in face (Like spinothalamic in body)
Mesencephalic nucleus of CN5 sense what?
Proprioception from muscles of mastication
what are pre-synaptic parasym CN?
3, 7, 9, 10
3= ciliary
7= pterygopalatine and submandibular
9= otic ganglian
V1 and V2 course anterioly thru?
cavernous sinud with 3, 4, 6 and internal carotid artery (while V3 dives through foramen ovale)
innervation to occular muscles?
3, 4 and 6
cavernous sinus thromobsis
- spread of clot, infection into cavernous sinus (affects V1 and V2)
- network of veins lonf face/orbit that allow for migration of septic thrombi to cavernous sinus (result in edema, ophthalmoplegia, facial analgesia)
- initially unilateral but presents bilateral
facial analgesia
only Vi and V2 (V3 dives down and ISN;T in cavernous sinus)
V1 aquires? innervates?
autonomics for lacrimal gland
*is only general sense to: dura mater, cornea, mucosa of nasal cavity and paranasal sinuses
V1 terminal branches over forehead?
supraorbital and supratrochlear
branches of V1
NFL is medial to lateral after passing through superior orbital fissue
*meningeal branch is off beofre fissure
what all passes through superior orbital fissure from V1?
lacrimal n, frontal n, nasociliary n (NFL)
herpes zoster ophalmicus
- 1/4 of herpes zoster cases
- commonly known as shingles
- shown along affect dermatome
V2 carries general sensory to?
nasal cavity, paranasal sinuses, palate, max teeth, max gums, max face
posterior superior alveolar nerve of V2 innervates?
max molars except MB root of 1st molar
ALL MAX TEETH INNERVATED BY?
v2
most of posterior septum innervated by?
nasopalatine nerve of V2
V1 is anterior
What does V3 carry?
- sense from inferior face, anterior 2/3 of tongue, mand teeth, TMJ, mucosa of oral cavity and anterolateral scalp
- motor of mastication, tensor veli palatini, mylohyoid, anterior belly and tensor tympani (levator veli palatini= vagus)
posterior vs anterior division of V3? exceptions
anterior= motor; long buccal exception posterior= sense; mylohyoid is exception
