CN XI Flashcards
What fibers are carried by the accesssory nerve?
exclusively motor
What are the wo roots of CN XI that contribute lower motor neurons?
cranial and spinal
What muscles are supplied by CN XI?
SCM, Trapz, and muscles of the soft palate, pharynx and larynx
Where are the cell bodies which contribute axons to the cranial root of the accessory nerve?
nucleus ambiguus
Where is the spinal nucleus of the accessory nerve found?
anterior horn of the gray matter
T/F: the spinal nucleus of the accessory nerve extends from the foramen magnum to the C7 cord level.
False; but it does extend from foramen magnum to the the C5 or C6 cord level
Where is the apparent origin of the cranial root CN XI?
MO
After the two roots of CN XI combine, where does CN XI exit the skull?
jugular foramen
What other cranial nerves share a common skull exit with CN XI?
IX and X
After exiting the skull, fibers from which root separate and join the vagus nerve?
fibers of the cranial root
Where do fibers from the cranial root of CN XI join the vagus nerve?
at the inferior ganglion
Where are the fibers of the accessory nerve, which are carried by the vagus, distributed?
pharyngeal plexus, external and recurrent laryngeal nerves as well as the motor supply of the laryngeal muscles
What is the only laryngeal muscle that CN XI does not supply motor info to?
cricoarytenoid (supplied by external laryngeal nerve)
What is the apparent origin of the spinal root of CN XI?
lateral aspect of cervical cord between anterior and posterior rootlets
Ascending rootlets combine into the spinal root, forming a trunk which will arise between what structures?
denticulate ligaments and posterior rootlets
Where does the spinal root of CN XI enter the skull?
foramen magnum (this is efferent info)
After the spinal root combines with the cranial root, what does it pass through?
jugular foramen
T/F: CN XI pierces teh SCM.
False; CN XI passes deep to SCM
T/F: CN XI traverses the posterior triangle and pierces teh trapezius muscle.
False; it traverses the posterior triangle but travels deep to the trapz
Considerable evidence suggests that the trapezius receives some motor supply from where (as well as from CN XI)?
from the cervical plexus with CN XI supplying the upper and middle portions and cervical plexus supplying the lower 2/3
A lesion of the spinal component of CN XI would lead to paralysis of the SCM on one side. What action would then be impossible?
turning of the face to the unaffected/contralateral side
T/F: spasmodic torticollis is relatively pain free.
False; it extremely painful
What is the condition described as episodic contraction of the SCM and Trapz?
spasmodic torticollis
What kind of info is carried by the C3 and C4 rootlets to the Trapz?
proprioceptive info and maybe motor
T/F: paralysis of the trapz leads to brachial plexus traction.
True
