Spinal Accessory And Hypoglossal Nerves Flashcards
What forms the spinal accessory nerve?
Confluence of c1-c5
A little component of nucleus ambiguous
What is the function of the 11th and 12th CN?
Motor
Where does the accessory nerve go?
Ascend in the vertebral column into the cranium through the foramen magnum through the subarachnoid and then exit through the jugular foramen. May have a cranial portion.
What are the two main muscles it innervates?
The trapezius and sternocleidomastoid
Where does the accessory nerve come off?
The anterior horn, a little boot, no defined nucleus
What happens if the lower motor neurons are damaged?
Weakness in the ipsilateral side, trouble turning your head in the opposite side
Same side damage
What is most of the accessory nerve in tract wise?
Corticospinal tract
Crosses at the pyramidal decussation
Where is the corticospinal tract?
Right by the spinal accessory nerve origin
Is the spinal accessory purely ipsilateral?
No
Somewhat bilateral because of the decussation
SCM is mostly ipsilateral
Trapezius is mostly contralateral
What is the sensory of the SCM muscles and traezius?
C2/3 and c2/4
Where does the hypoglossal nerve come from?
Base of ventral medulla between pyramids and olive
What does the hypoglossal nerve innervate?
Innervates muscles of the ipsilateral tongue (eating, speech, breathing)
Where is the nucleus of the hypoglossal nerve located?
In the floor of the ventricle of the rostal medulla
What does CN XII branch into?
Ansa cervicalis
What happens with damage to the hypoglossal nerve?
Lower motor neuron damage results in ipsilateral atrophy
