8. Brain & Cranial Nerves Pt. 2

Question 1

Identify this nerve.

Answer 1

Trigeminal nerve (CN V)

Question 2

Describe the trigeminal nerve and its 3 main branches IN GENERAL

Answer 2

TRIGEMINAL NERVE CN V

• comes out of the pons
• has 2 roots: sensory and motor: mostly responsible for sensory
• has 3 branches:
  1. CN V1: OPHTHALMIC NERVE
• comes out the superior orbital fissure
• general sensory of eyes and forehead
  2. CN V2 MAXILLARY NERVE
• comes out the foramen rotundum
• general sensory of cheek
  3. CN V3: MANDIBULAR NERVE
• comes out of the foramen ovale
• general sensory and motor!

Question 3

Draw out where each of the 3 branches innervate the face.

Answer 3

Question 4

Describe the ophthalmic nerve (CN V1).

Answer 4

(1st branch of the trigeminal nerve)

from the pons: trigeminal n -> trigeminal ganglion (which gives off the 3 branches) -> superior orbital fissure ->becomes frontal n ->

1. goes to innervate lacrimal gland (tears)
2. becomes the supraorbital n that goes thru the supraorbital foramen to do forehead

Question 5

What covers the trigeminal ganglion?

Answer 5

meninges

Question 6

Describe the maxillary nerve CN V2.

Answer 6

trigeminal n -> trigeminal ganglion -> maxillary n (cn v2) -> foramen rotundum ->

1. innervates maxillary teeth (upper teeth), palet, mucosa
2. gives off the infraorbital n which goes through the infraorbital foramen to do cheeks and nose sensory

Question 7

Describe the mandibular n (CN V3).

Answer 7

trigeminal n -> trigeminal ganglion -> mandibular n -> foramen ovale ->
1. inferior alveolar n -> mandibular foramen -> (travels through the mandible & inn mandibular teeth) -> mental foramen -> mental n

2. lingual n: does general sensory of anterior 2/3 of tongue and sublingual gland
3. buccal n: innervates mastication muscles and tenses cheek (pushes food back, blow a balloon)

(buccal on top of lingual on top of inferior alveolar)

Question 8

Identify the nerve:

Answer 8

CN VII: facial n

Question 9

T/F: the facial nerve is only sensory innervation.

Answer 9

False, both sensory and motor

Question 10

What does the facial nerve innervate? ?(4)

Answer 10

facial nerve (cn vii) -> internal acoustic meatus ->

1. parasympathetic branches innervate the lacrimal gland, nose, palate
2. gives off chordae tympani before entering stylomastoid foramina: chordae tympani joins with lingual n (of the manidbular n) and does special sensory of the anterior 2/3 tongue (taste)
3. parasympathetic fibers to sublingual and submandibular glands (salivary and inflame when sick)
4. through the stylomastoid foramina: gives off motor branches to muscle of facial expression

Question 11

Identify the various structures.

Answer 11

green: parotid gland: covers the facial n
purple: parotid duct

Question 12

What are the various motor branches of the facial n?

Answer 12

facial n does innervation of the muscle of facial expression

To Zanzibar By Motor Car

1. temporal branch
2. zygomatic branch (cheek)
3. buccal branch
4. mandibular branch
5. cervical branch (neck)

Question 13

Identify this nerve.

Answer 13

Vestibulocochlear n (CN VIII)

Question 14

Identify the various parts of the ear.

Answer 14

a. external ear
b. tympanic membrane
c. middle ear
d. osicles
e. vestibular apparatus
f. inner ear
g. eustachian tube = pharyngotympanic tube
h. pharynx.
i. cochlea

Question 15

What does your vestibulocochlear nerve innervate? What type of nerve is it?

Answer 15

vestibularcochlear runs with facial nerve to ear through the internal acoustic meatus: gives off 2 branches:

1. cochlear branch (for hearing)
2. vestibular branch (for proprioception and balance)

=special sensory nerve

Question 16

Where do the vestibular apparatus and cochlea situate in the skull

Answer 16

in the petrous bone

Question 17

Identify this nerve.

Answer 17

Glossopharyngeal n (CN IX)

Question 18

What does the glossopharyngeal nerve innervate? What kind of nerve is it? (4)

Answer 18

both motor and sensory nerve

goes through the jugular foramen (with the jugular vein)

1. gives general and special sensory to posterior 1/3 of tongue
2. gives motor branches to pharyngeal muscle
3. gives parasympathetic branches to the parotid gland
4. gives sensory to carotid sinus

Question 19

What is the innervation of the lacrimal gland?

Answer 19

• facial nerve CN VII - parasympathetic sympathetic innervation
• sensory innervation from ophthalmic nerve CNV1 and maxillary nerve CNV2

Question 20

What type of nerve is the vagus nerve? Describe it? Who does it travel with? What does it innervate? Does it have any branches, if so what are they?

Answer 20

• Vagus nerve is both a sensory and motor nerve.
• It comes out with the glossopharyngeal and spinal accessory n.
• travels with the jugular vein and internal carotid artery in the carotid sheet through the jugular foramen
• it has the recurrent laryngeal branches that innervate the motor control of the vocal folds
• INNERVATION:
  1. does motor innervation of pharynx and larynx
  2. does sensory innervation of larynx
  3. does parasympathetic innervation of the esophagus

Question 21

Through the jugular foramen, what can be found between the jugular vein and internal carotid artery?

Answer 21

1. vagus nerve
2. glossopharyngeal n
3. spinal accessory nerve (only vagus travels through the carotid sheet with the jugular vein and internal carotid)

Question 22

What nerve is this?

Answer 22

the spinal accessory nerve CN XI

Question 23

In which foramen does the spinal accessory nerve travel through? What forms the spinal accessory nerve? What does it innervate? What type of nerve is it?

Answer 23

• spinal accessory nerve formed of the spinal root (from the cervical spinal cord) and the cranial root (from the brainstem that goes into to join the vagus n)
• spinal accessory travels into the foramen magnum and leaves through the jugular foramen
• motor innnervation of the sternocladomastoid and trapezius muscle
• motor nerve

Question 24

Where does the vagus nerve gets its motor innervation from?

Answer 24

from the cranial root (from brainstem) because its so close to vagus nerve

Question 25

Identify this nerve.

Answer 25

hypoglossal n

Question 26

Where does the hypoglassal nerve travel? What does it innervate? What type of nerve is it?

Answer 26

• motor n
• Travels through the hypoglossal canal that goes through occipital canal travelling under the tongue
• does motor innervation of extrinsic muscles of tongue and intrinsic muscle of tongue (fine motor movement)

Question 27

Summarize all the cranial nerves, identifying which foramina they travel through and what their function is. (use mnemonics)

Answer 27

Question 28

Summarise the parasympathetic innervation by cranial nerves.

Answer 28