CN XI

Question 1

What fibers are carried by the accesssory nerve?

Answer 1

exclusively motor

Question 2

What are the wo roots of CN XI that contribute lower motor neurons?

Answer 2

cranial and spinal

Question 3

What muscles are supplied by CN XI?

Answer 3

SCM, Trapz, and muscles of the soft palate, pharynx and larynx

Question 4

Where are the cell bodies which contribute axons to the cranial root of the accessory nerve?

Answer 4

nucleus ambiguus

Question 5

Where is the spinal nucleus of the accessory nerve found?

Answer 5

anterior horn of the gray matter

Question 6

T/F: the spinal nucleus of the accessory nerve extends from the foramen magnum to the C7 cord level.

Answer 6

False; but it does extend from foramen magnum to the the C5 or C6 cord level

Question 7

Where is the apparent origin of the cranial root CN XI?

Answer 7

MO

Question 8

After the two roots of CN XI combine, where does CN XI exit the skull?

Answer 8

jugular foramen

Question 9

What other cranial nerves share a common skull exit with CN XI?

Answer 9

IX and X

Question 10

After exiting the skull, fibers from which root separate and join the vagus nerve?

Answer 10

fibers of the cranial root

Question 11

Where do fibers from the cranial root of CN XI join the vagus nerve?

Answer 11

at the inferior ganglion

Question 12

Where are the fibers of the accessory nerve, which are carried by the vagus, distributed?

Answer 12

pharyngeal plexus, external and recurrent laryngeal nerves as well as the motor supply of the laryngeal muscles

Question 13

What is the only laryngeal muscle that CN XI does not supply motor info to?

Answer 13

cricoarytenoid (supplied by external laryngeal nerve)

Question 14

What is the apparent origin of the spinal root of CN XI?

Answer 14

lateral aspect of cervical cord between anterior and posterior rootlets

Question 15

Ascending rootlets combine into the spinal root, forming a trunk which will arise between what structures?

Answer 15

denticulate ligaments and posterior rootlets

Question 16

Where does the spinal root of CN XI enter the skull?

Answer 16

foramen magnum (this is efferent info)

Question 17

After the spinal root combines with the cranial root, what does it pass through?

Answer 17

jugular foramen

Question 18

T/F: CN XI pierces teh SCM.

Answer 18

False; CN XI passes deep to SCM

Question 19

T/F: CN XI traverses the posterior triangle and pierces teh trapezius muscle.

Answer 19

False; it traverses the posterior triangle but travels deep to the trapz

Question 20

Considerable evidence suggests that the trapezius receives some motor supply from where (as well as from CN XI)?

Answer 20

from the cervical plexus with CN XI supplying the upper and middle portions and cervical plexus supplying the lower 2/3

Question 21

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?

Answer 21

turning of the face to the unaffected/contralateral side

Question 22

T/F: spasmodic torticollis is relatively pain free.

Answer 22

False; it extremely painful

Question 23

What is the condition described as episodic contraction of the SCM and Trapz?

Answer 23

spasmodic torticollis

Question 24

What kind of info is carried by the C3 and C4 rootlets to the Trapz?

Answer 24

proprioceptive info and maybe motor

Question 25

T/F: paralysis of the trapz leads to brachial plexus traction.

Answer 25

True