Spinal Accessory and Hypoglossal Nerve Pathways Flashcards
What neuron fibers form the spinal accessory nerve?
C1-C5 lower motor neurons fibers that emerge from the cervical cord
Where does the spinal accessory nerve go FIRST?
It ascends into the cranium in the CSF-filled subarachnoid space through the foramen magnum
THrough what foramen does the spinala ccessory nerve exit the skull?
the jugular foramen
What does the spinal accessory nerve innervated?
the trapezius and sternocleidomastoid
THe motor rootlets that make up XI originate in what portion of the cervical spinal cord?
in the posteriolateral portion of the ventral horn
Weakness in turning the head to the right suggests damage to which muscle?
the left sternocleidomastoid/left spinal accessory nerve
With injury to the spinal accessory nerve, what will the shoulder look like on the affected side?
It will doop
From what area of the brain stem does the hypoglossal nerve exit? Medial or lateral?
the ventral medulla between the pyramids and olive (so medial)
What muscles are innervated by the hypoglossal nerve?
ipsilateral tongue muscles
Where is the nucleus of the hypoglossal nerve located?
near the midline in the floor of the ventricle of the rostral medulla
What happens tot he tongue if you damage the hypoglossal nerve?
The ipsilateral muscles will atrophy, so when you stick the tongue out, it will deviate to the affected side
When there is uppe rmotor damage to the corticobulbar tract, which way will the tongue deviate? Why?
Corticobulbar axons provide mostly contralateral innervation, so it will deviate away from the side of the lesion.
Why do patients differ in the degree of tongue deviation in corticobulbar damage?
there is some genetic variability in the degree of ipsilateral vs. bilateral corticobulbar projects
