Trigeminal nerve 2 (CNV3) Flashcards
Out of CNV1,2 and 3 what is the most important for us
CNV3 (mandibular)
what does sensory info does CNV3 provide
temple, jaw, chin, anterior 2/3 tongue, floor of mouth along with lower teeth and gums, lower lip
what motor info does CNV3 provide
muscles of mastication + a couple of others
What is the course of CNV3
passess through the foramen ovale and into the infratemporal fossa where it gives several branches
after the trigeminal ganglion where do each of the 3 branches go
CNV1 - superior orbital fissure
CNV2 - foramen rotundum
CNV3 - foramen ovale
CNV3 exits into less protected structure than CNV1 and 2, advantage and disadvantage of this? (infratemporal fossa no bone)
advantage - can target easier
disadvantage - branches are vulnerable to injury
Boundaries of the infratemporal fossa
- not continuous
- not all connected
i. e. if you have a dislocation, branches of CNV3 can be affected
laterally: ramus of mandible
medially: lateral pterygoid plate of sphenoid bone
anteriorly: posterior aspect of maxilla
superiorly: infratemporal crest of sphenoid bone
inferiorly: angle of mandible
What are the main branches of the mandibular division
- Auriculotemporal
- Buccal
- Mental
- lingual
- muscular
What info does the mandibular branch carry
Parasympathetics via submandibular and otic ganglia to submandibular and sublingual glands and parotid gland
Before CNV3 divides into anterior and posterior branches, what other small branches are there? are these sensory or motor?
- Meningeal branch (sensory)
- Branch to tensor tympani (motor)
- Branch to tensor veli palatini (motor)
- Nerve to medial pterygoid (motor)
What does the meningeal branch do
sensory to dura mater
What does the branch to tensor tympani do
- In middle ear, 3 little bones to help vibrations, 2 muscles attach to these, control vibration of ear walls
(If someone presents to injury of CNV3, very sensitive to loud noises + sensory problems in temple, jaw, chin, inability to close jaw)
What does the branch to tensor veli palatini do
elevation of soft palate
What are the branches of the anterior trunk of the mandibular division? are they sensory or motor?
- deep temporal nerves (motor)
- nerve to lateral pterygoid (motor)
- buccal nerve (sensory)
- anterior trunk (motor)
- masseteric nerve (motor)
How is the buccal branch CNV3 different to the buccal branch of CNVII
CNV3 - infratemporal fossa, behind mandible, sensory
CNVII - facial nerve, superficial, motor
What are the posterior branches of CNV3? are they sensory or motor?
- auriculotemporal (sensory)
- lingual (sensory)
- inferior alveolar (mixed)
In what way is the inferior alveolar nerve sensory and motor
Higher up (superiorly) the inferior alveolar nerve is a mixed nerve, then divides into 2:
- mylohyoid (motor component goes with this nerve)
- after it loses it’s motor component, the rest of the nerve is sensory
What part of CNV3 supplies general sensation to the anterior 2/3rds of the tongue
lingual nerve
What is the term for terrible pain usually associated with CNV3 pain
trigeminal neuralgia
What nerves provide which parts of the oral cavity general sensory supply
- Buccal nerve to cheek and lateral gum
- Inferior alveolar nerve (+incisive nerve) to lower teeth
- Inferior alveolar nerve (mental nerve) to skin of chin and lower lip (both skin and mucous membranes)
What is the course of the inferior alveolar nerve
- supplies the mylohyoid and anterior belly of digastric
- before entering the mandibular foramen
- to supply general sensation to the lower teeth
what nerve supplies the lower teeth general sensory supply
inferior alveolar nerve
incisive branch = 1-4, main trunk = 5-8
what nerve supplies the buccal aspect of the gingiva next to teeth 6-8 on the lower arch
buccal nerve
what nerve supplies the buccal aspect of the gingiva next to teeth 1-5 on the lower arch
mental nerve (from inferior alveolar
what nerve supplies the lingual aspect of the gingiva next to teeth 1-8 on the lower arch
lingual nerve
What nerve is involved in general sensation (not taste) to the anterior 2/3rds of the tongue
CNV3 via lingual nerve
What nerve is involved in special sensation (taste) to the anterior 2/3rds of the tongue
facial nerve via chorda tympani
what part of the tongue is the trigeminal nerve involved in
general sensation (pain and temp) to the anterior 2/3rds
what part of the trigeminal nerve has the motor root for the muscles of mastication
CNV3
what are the muscles of mastication
- temporalis
- masseter
- lateral pterygoid
- medial pterygoid
what muscles of mastication close the mouth (elevators)
- temporalis
- masseter
- medial pterygoid
what does the temporalis do
close the mouth (elevator)
what does the masseter do
close the mouth (elevate)
what does the medial pterygoid do
close the mouth (elevator)
what does the lateral pterygoid do
opens the mouth (depresses)
what is the only muscle of mastication to open the mouth
lateral pterygoid
apart from the muscles of mastication, what else does CNV3 supply
- tensor tympani muscle in the middle ear
- tensor palati
- mylohyoid
- anterior belly of digastric
What happens during the jaw jerk reflex
The response to the stimulus is monosynaptic, with sensory neurons of the trigeminal mesencephalic nucleus sending axons to the trigeminal motor nucleus, which in turn innervates the masseter. This reflex is used to judge the integrity of the upper motor neurons projecting to the trigeminal motor nucleus. Both the sensory and motor aspects of this reflex are through CN V
What nerve supplies the skin of the angle of the mandible?
cervical plexus with the great auricular nerve (C2 and C3)
NOT CNV!!!
what is hutchinson’s sign
shingles on the tip of nose (increases likelihood of ocular complications via nasociliary nerve)
You should always aspirate to avoid…
- hitting a vein
- hitting an artery
- hitting a muscle
- hitting facial nerve
if you hit a vein with LA what’s the most likely to hit
pteryoid plexus
if you hit an artery with LA what’s the most likely to hit
could hit lots
if you hit a muscle with LA what’s the most likely to hit and what would happen
- medial pterygoid
- trismus
if you hit the facial nerve with LA what’s most likely to happen
- unilateral palsy??
- ipsilateral palsy??
facial nerve palsy is v rare (will resolve after a day or 2)
what nerve supplies all the muscle of facial expression
facial nerve
