CN XII Flashcards
What is the name of CN XII?
Hypoglossal
What kind of info is carried by CN XII?
exclusively motor
What muscles are supplied by the hypoglossal nerve?
intrinsic and extrinsic muscles of the tongue, except for the palatoglossus
What nucleus contains the cell bodies of the axons that form CN XII?
nucleus of the hypoglossal nerve
Where is the nucleus of the hypoglossal nerve located?
floor of the rhomboid fossa (in the MO)
What is the apparent origin of CN XII?
a series of rootlets arise from the sulcus between the pyramid and the olive of the MO.
How many bundles are formed by the rootlets of the hypoglossal nerve?
2
How do the bundles of the hypoglossal nerve exit the skull?
exit through the hypoglossal canal as separate entities and combine upon exiting the canal.
After exiting the skull, CN XII forms a loop to reach the base of the tongue. What is the name of this loop?
the arch of the hypoglossal nerve
Where are the fibers of the hypoglossal nerve sent after forming the arch of the hypoglossal nerve?
fibers are then distributed into terminal branches supplying the muscles of the tongue
T/F: some fibers from the first (and likely the second) cervical nerves travel with and become incorporated into CN XII.
False; these fibers travel with but do not become incorporated with CN XII
Fibers from C1 and C2 nerves which travel with CN XII separate to form what structure?
superior root of the ansa cervicalis
T/F: some cervical fibers will continue with the hypoglossal nerve to ultimately supply the geniohyoid and thyrohyoid muscles.
True
What muscles are supplied by the lingual branches of the hypoglossal nerve?
hyoglossus, genioglossus, and styloglossus
Where are the fibers of the lingual branches of CN XII originally from?
the cervical plexus originally
