Facial Nerve Pathway

Question 1

Is the facial nerve sensory, motor or mixed?

Answer 1

mixed

Question 2

Describe the branchial motor supply of the facial nerve?

Answer 2

this is the major role…

efferent supply to the ipsilateral muscles of facial expression and the stapedius

Question 3

Describe the visceral motor function of the facial nerve

Answer 3

sends preganglionic parasympathetics to the lacrimal, sumandibular, and sublingual glands

Question 4

Describe the somatic sensory properties of the facial nerve.

Answer 4

afferent supply to the ipsilateral part of outer ear, nasal cavity and soft palate

Question 5

Describe the visceral (special) sensory properties of the facial nerve

Answer 5

ipsilateral affterent supply for TASTE to the anterior 2/3 of the tongue

Question 6

Where is the facial motor nucleus located?

Answer 6

in the ventrolateral caudal pons

Question 7

Where do ribers leave the facial motor nucleus?

Answer 7

exit up and over the abducens at the genu and then out from the lasteral pons

Question 8

What will damage to the facial nerve or its motor nucleus cause?

Answer 8

paralysis of the muscles on the same side of the face

Question 9

Describe the corneal blink reflex. What two CN are involved?

Answer 9

CN 5 and 7:

You touch the cornea and sensory efferents travel in V2 to the trigeminal ganglion and then descend in the spinal trigeminal tract to the rostral spinal trigeminal nucleus.

output from the spinal trigeminal nucleus it to BILATERAL motor nuclei of the facial nerve

efferents from the motor nuclei of the facial nerve to the orbicularis oculi cause the bilateral blink.

Question 10

What is special about coricobulbar tract output to the facial motor nuclei?

Answer 10

Most output is bilateral to cranial nerve nuclei, but that’s not the case with the facial motor nucleus - it’s different depending on where you are on the face:

lower half of the face: corticobulbar fibers to the motor neurons are contralateral

upper half: corticobulbar fibers are distributed bilaterally

Question 11

Because of the odd corticobulbar innervation to the facial nerve, what will UNILATERALcorticobulbar damage cause?

Answer 11

weakness of only the contralateral LOWER quadrant of the face

Question 12

Paralysis of the entire left face resulted from what type of lesion?

Answer 12

The ipsilateral lowe rmotor neuron

Question 13

Paralysis of the left lower face only resulted form what type of lesion?

Answer 13

contralateral upper rmotor neuron damage

Question 14

Is bell’s palsy a lowe rmotor neuron lesion or an upper motor neuron lesion?

Answer 14

lower motor neuron - you get paralysis of entire ipsilateral face