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
