Corticonuclear projections to the cranial nerve motor nuclei Flashcards
The trigeminal nucleus receives what patterning of UMN projections?
Bilateral to cranial nerve 5 from the corticonuclear axon terminals.
The facial nucleus recieves what patterning of UMN projections?
The facial nerve is split into upper and lower portions.
The upper receives bilateral innervation.
The lower half receives contralateral innervation.
The nucleus ambigus CNXI recieves what patterning of UMN projections?
Receives ipsilateral projections.
The hypoglossal nucleus receieves what patterning of UMN projections?
Recieves bilaterall with the one exception of the nerves that innervate the GENIOGLOSSUS MUSCLE.
The genioglossus muscle is innervated contralaterally.
The oculomotor, trochlear, and abducens nerve receive innervation from where?
Do not receive corticonuclear fibers instead receive motor messages from frontal and parietal eye fields via DIFFERENT NERVES THAT STOP IN THE RETICULAR FORMATION BEFORE GIVING TO 3,4,6 NUCLEI.
What is the patterning of the UMN projections to the trigeminal motor nucleus?
At the pontine level the corticonuclear nerves terminate bilaterally onto interneurons within the reticular formation near the V motor nucleus.
In an UMN damage to cranial nerve 7 the upper half of the face is unaffected, why is this?
Because the nerves to the upper half are projected bilaterally, there is more than enough coverage to make sure power stays in tact.
The lower half however, is contralaterally only which does not provide the same safety.
Why is it that continued problems are noted on the same side in the body as the facial disfigurement?
The corticonuclear fibers travel very close to the corticospinal fibers in the internal capsule, the basis pedunuli, and the pyramid of the medulla.
What is the Corticonuclear nerve patterning to the nucleus ambiguus?
Covers CN 9 and 10 with an ipsilateral innervaton within the cervical spinal cord.
What is the corticonuclear patterning to the hypoglossal nucleus?
Patterning is bilaterall except to the genioglossus which is contralateral.
The tongue deviating to one side when sticking tongue out displays damage to nervous supply to which muscle?
Damage to the genioglossus due to its contralateral innervation.
The tongue will deviate towards the weakened side.
Name the eye movement control centers for CN 3,4, and 6
What patterning do these nerves follow?
The midbrain reticular formation
and
paramedian pontine reticular formation.
These have contralateral patterning.
Why do injuries to the corticonuclear tract commonly affect the corticospinal tract as well?
The corticonuclear tract descends in the genu of the internal capsule and then travels along the anterior part of the posterior limb of the internal capsule.
The corticospinal tract descends on the anterior potion of the posterior limb of the internal capsule!!!
What blood supply if clotted would knock out both the corticonuclear and corticospinal tracts?
The lenticulostriate arteries supplying the Genu and posterior limb of the internal capsule.
Where does the corticonuclear tract travel very closely to the corticospinal tract?
What arteries supply this area?
Travels just medial to the corticospinal tract in the basis pedunculii of the midbrain.
This is supplied by the posterior cerebral artery and the basilar artery.
