Accessory Nerve XI

Question 1

Where are the LMN that innervate a few of the laryngeal muscles (cranial component) located for cranial nerve XI?

Answer 1

In Nucleus Ambiguus

Question 2

What do the LMN of the cranial component of CN XI innervate?

Answer 2

A few of the Laryngeal muscles

Question 3

What do the LMN of the spinal component of CN XI innervate?

Answer 3

Sternocleidomadotid and trapezius muscles

Question 4

Where are the cell bodies of the LMN for the spinal component located?

Answer 4

Cervical levels of the spinal cord (dorsal to the ventral horn

Question 5

Where do the axons of the spinal component leave the spinal cord and ascend to?

Answer 5

The cranial cavity to re-exit the skull as the accessory nerve

Question 6

For the cranial component a small number of fibers exit the medulla along with what nerve?

Answer 6

The Vagus Nerve

Question 7

UMN (corticobulbar fibers) decent with the corticospinal fibers and decussate where?

Answer 7

At the Pyramidal decussation and terminate in the cervical region C2-C4

Question 8

Clinically to test for involvement of the spinal part of CN XI the patient is asked to do what?

Answer 8

Turn their head to the side and shrug their shoulders

Question 9

Clinically to test for involvement of the cranial component what is the patient asked to do?

Answer 9

Nothing…. the cranial component is indistinguishable from the vagus nerve