CN XII Flashcards
What is the name of CN XII?
hypoglossal nerve
What number is the hypoglossal nerve?
CN XII
How is the hypoglossal nerve classified?
exclusively motor
What does CN XII innervate?
intrinsic and extrinsic muscles of the tongue
NOT palatoglossus
What type of fibers are in CN XII?
LMN’s somatic motor fibers
What CN’s carry sensation from the area supplied by CN XII?
CN; V, VII, IX
Where are cell bodies of CN XII found?
nucleus of the hypoglossal nerve
Where is the nucleus of the hypoglossal nerve found?
floor of the rhomboid nucleus
What is another name for the nucleus of the hypoglossal nerve?
“hypoglossal nucleus”
What is the apparent origin of CN XII?
series of rootlets in the sulcus between the pyramid and olive of the medulla oblongata
How does CN XII exit the skull?
hypoglossal canal
How does CN XII travel after exiting the hypoglossal canal?
descends forming a loop to reach teh base of the tongue
What is the loop of CN XII nerve called?
arch of the hypoglossal nerve
After the hypoglossal nerve reaches the base of the tongue what does it do?
terminal branches reach the muscles of the tongue
What fibers travel with but aren’t part of the hypoglossal nerve?
C1 and C2 fibers
When the C1 and C2 fibers separate from the hypoglossal nerve what do they form?
superior root of the ansa cervicalis
What do the cervical fibers that continue with the hypoglossal nerve innervate?
geniohyoid and thyrohyoid muscles
What do the lingual branches of the hypoglossal nerve innervate?
hyoglossus, genioglossus, and styloglossus muscles
What muscle is not innervated by the hypoglossal nerve?
palatoglossus nerve
How can the tongue be used to diagnose problems with the hypoglossal nerve?
tongue will not stick out straight
What direction does the tongue point with hypoglossal nerve damage?
points to the damaged side
HEMIATROPHY
How can swallowing be evaluated for hypoglossal nerve damage?
the larynx will deviate to the “normal” unaffected side
