Trigeminal Flashcards
What base of skull foramina does CNV1 pass through?
Superior orbital fissure
What base of skull foramina does CNV2 pass through?
Foramen rotundum
What base of skull foramina does CNV3 pass through?
Foramen ovale
What type of information is carried on CNV1?
Sensory
What type of information is carried on CNV2?
Sensory
What type of information is carried on CNV3?
Sensory and motor
What are the sensory functions of CNV?
Somatosensation of the face, mouth, anterior 2/3rds of tongue, sinuses and supratentorial meninges / proprioception associated with chewing
CNV supplies the motor control to which muscles?
Muscles of mastication, tensor tympani, tensor veli palatini, mylohyoid, anterior belly of digastric
Where does the trigeminal nerve connect to the CNS?
At the pons (laterally, midway between midbrain and medulla)
Once the trigeminal nerve has connected with the CNS at the pons, describe its intracranial path?
Travels inferior to the edge of the tentorium cerebelli between the posterior and middle cranial fossa
Describe the extracranial path of the sensory axons of CNV?
Course from the superficial and deep structures of the face to their respective cranial formina
Describe the extracranial path of the motor axons of CNV?
Course from the foramen ovale towards the skeletal muscle they supply
What are the specific regions of the face supplies by CNV1, V2 and V3?
V1 = ophthalmic, V2 = maxillary, V3 = mandibular
What are some areas of the face which are supplied by CNV1?
Upper eyelid, cornea, conjunctiva, skin of the root/bridge/tip of the nose
Which specific part of CNV is responsible for the afferent limb of the corneal reflex?
CNV1
What are some areas of the face which are supplied by CNV2?
Lower eyelid, maxilla, ala of the nose, upper lip
What are some areas of the face which are supplied by CNV3?
Skin over the mandible and TMJ
What is the sensory supply to the angle of the mandible?
C2, 3 - great auricular nerve
Where are trigeminal sensory cell bodies located? Where do their projections terminate?
In the trigeminal ganglion / the trigeminal nucleus
Where is the trigeminal sensory ganglion found?
In the middle cranial fossa
Describe the sensory nucleus of the trigeminal nerve?
Forms a long column of neurones which stretch from the midbrain down to the upper two segments of the cervical spinal cord
Describe the function of the mesencephalic nucleus (part of the sensory nucleus of the trigeminal nerve)?
Proprioception information from the muscles of mastication
Describe the function of the pontine trigeminal nucleus (part of the sensory nucleus of the trigeminal nerve)?
Touch and vibration
Describe the function of the spinal nucleus (part of the sensory nucleus of the trigeminal nerve)?
Pain and temperature
What is unusual about the mesencephalic nucleus (part of the sensory nucleus of the trigeminal nerve)?
It is the only sensory nucleus within the CNS
What is the function of the ventral trigeminothalamic tract?
Passes the sensory fibres of CNV through the thalamus and into the cortex
The motor neurones of CNV originate where?
In the trigeminal motor nucleus
Describe the innervation of the LMNs of CNV?
They receive bilateral innervation from the UMNs
What are the three pairs of jaw closing muscles supplied by CNV3?
Masseter, temporalis and medial pterygoid
What is the one pair of jaw closing muscles supplied by CNV3?
Lateral pterygoid
What does the mylohyoid muscle do?
Opens the mouth for swallowing and speech
What does the anterior belly of digastric muscle do?
Also helps to open the mouth
What does the tensor veli palatini muscle do?
Tenses the palate during swallowing
What does the tensor tympani muscle do?
Tenses the tympanic membrane of the ear to reduce vibrations
How is the sensory function of CNV tested?
By asking the patient to close their eyes and touch their skin in each region - ask the patient to tell you when they can feel something and compare the two sides
How can the motor function of CNV be tested?
Palpate the strength of contraction of the masseter and temporalis muscles by asking the patient to clench their teeth / ask the patient to open their jaw against resistance
