Trigeminal Nerve Flashcards
what is the sensory functions for CN V?
general sensation for all 3 divisions
what is the motor functions for CN V?
- somatic motor only
- mandibular division only: muscles of mastication, mylohyoid, anterior belly of digastric, tensor veli palatini, tensor tympani
what is the sensory function for maxillary division V2 of CN V?
- lower eyelid and its conjunctiva
- inferior posterior portion of the nasal cavity (superior anterior is V1)
- cheeks and maxillary sinus
- lateral nose
- upper teeth, lip and gingiva
- superior palate
what is the SENSORY function for mandibular division V3 of CN V?
- facial skin in the lower third of the face; including the chin and the lower lip
- inferior row of teeth and gingiva
- anterior 2/3 of the tongue; general sensation only taste is conveyed by chorda tympani CN VII
what is the MOTOR function for mandibular division V3 of CN V?
4 muscles of mastication
- temporalis
- masseter
- lateral pterygoid
- medial pterygoid
4 other muscles
- tensor veli palatini
- tensor tympani
- mylohyoid
- anterior belly of digastric
where is the trigeminal motor nucleus located ?
mid pons, with fascicles that join CN V3
where are the UMN and LMN cell bodies located for the muscles of orofacial region?
UMN
- pre-central gyrus of primary motor cortex
LMN
- trigmeninal motor nucleus in the mid pons for CN V3
what are the projections for the UMN?
primary motor cortex —–> corona radiata —–> internal capsule ——> crus cerebri ——> CN V nucleus
what are the projections for the LMN?
motor nuclei of CN V —-> trigeminal ganglion —-> V3 —–> muscles of mastication
do the CN V UMN project bilaterally or contralaterally? what does this mean if there is a lesion to an UMN?
bilaterally, meaning a lesion to the UMN will usually not produce symptoms
do the CN V LMN project bilaterally or ipsilaterally? what does this mean if there is a lesion to a LMN?
ipsilaterally, a lesion would cause loss of motor function on the same side as the lesion
what are the sensory modalities for cutaneous receptors and their specific nuclei?
- proprioception: mesencephalic nucleus
- touch, pressure and vibration: main sensory nucleus
- pain and temperature: spinal nucleus
what is the trigeminal pain pathway?
1st order neuron
- receptors peripherally synapse at the trigeminal spinal nucleus
2nd order neuron
- spinal nucleus conveys pain through trigeminothalamic tract that decussates then projects to the thalamus
3rd order neuron
- synapse at the VPM nucleus of the thalamus and project through the posterior limb of internal capsule to the primary somatosensory cortex
explain the thalamo-cortical projection for pain?
- neurons in the VPM send axons to posterior limb of the internal capsule
- neurons ascend to the primary somatosensory cortex in the post central gyrus
cranial parasympathetic outflow comes from what 4 cranial nerves and what are their associated ganglion?
- CN III: ciliary ganglion
- CN VII: pterygopalatine and submandibular ganglion
- CN IX: otic ganglion
- CN X: ganglion in sacral and lumbar regions
what is the pathway for CN III parasympathetic fibers?
- PREganglionic fibers in CN III
- synapse in ciliary ganglion
- POSTganglionics hitchhike on short ciliary nerve (CN V1)
what is the pathway for CN VII parasympathetic fibers?
PREganglionic fibers in CN VII
1. synapse in pterygopalatine ganglion and postganglionic fibers travel along CN V2 and V1 branches to the LACRIMAL gland
2. synapse in submandibular ganglion and postganglionic fibers travel along CN V3 (lingual nerve) to the submandibular and sublingual glands
what is the pathway for CN IX parasympathetic fibers?
- PREganglionic fibers in CN IX
- synapse in otic ganglion
- POSTganglionics hitchhike on auriculotemporal nerve (CN V3)
what symptoms would be present in a patient with a lesion in the inferior portion of the cavernous sinus?
diplopia worse with left lateral gaze and numbness on left side of her face in V1 and V2 regions
