Accessory and Hypoglossal - Michaels

Question 1

What foramen does the spinal accessory nerve pass through?

What does the nerve innervate?

Answer 1

Ascends through the foramen magnum and descends back out the jugular foramen

Innervates the sternocleidomastoid and the trapezius

Question 2

Where SPECIFICALLY does the spinal accessory nerve originate?

Answer 2

The posteriolateral portion of the anterior horn in the cervical spine

Question 3

How will a spinal accessory nerve lesion affect the sternocleidomastoid msucle?

Answer 3

Weakness of this muscle in turning the head toward the side opposite the lesion

Question 4

CN 12 damage, obvious sign?

Answer 4

Tongue deviates toward lesion when stuck out

Question 5

Corticobulbar tract damage (upper motor neuron) will cause what problem in the hypoglossal path?

Answer 5

Now the tognue will deviate away from the side of the upper motor neuron lesion

Question 6

When it comes to upper motor neuron damage (corticbulbar tract). Why would the maount of tongue deviation chage from perosn to person?

Answer 6

The corticobulbar tract actually innervates bilaterally it’s just that MOST of the innervation of CN12 is contralateral. It all depends on the person as far as how little is ipsilateral. This will determine how little innervation the tongue now has from upper motor neurons