Cranial Nerves

Question 1

How many pairs of Cranial Nerves are there?

Answer 1

12

Question 2

How are Cranial Nerves designated?

Answer 2

With Roman Numerals

Question 3

What is Cranial Nerve I?

Answer 3

Olfactory Nerve

Question 4

What is the function of the Olfactory Nerve (CN I)?

Answer 4

Mediates the sense of smell, observed when the pet sniffs around its environment.

Question 5

What is Cranial Nerve II?

Answer 5

Optic Nerve

Question 6

What is the function of the Optic Nerve (CN II)?

Answer 6

• Carries visual signals from the retina to the occipital lobe of the brain, observed as the pet tracks an object with its eyes.
• Causes pupil constriction.

Question 7

What is the Menace response?

Answer 7

The waving of the hand at the dog’s eye to see if it blinks. CN II provides the vision, CN VII causes the pet to blink.

Question 8

What is Cranial Nerve III?

Answer 8

Oculomotor Nerve

Question 9

What is the function of the Oculomotor Nerve ( CN III)?

Answer 9

Provides Motor to most of the extraocular muscles (dorsal, ventral and medial rectus) and for pupil constriction. We observe pupil constriction in PLR.

Question 10

What is Cranial Nerve IV?

Answer 10

Trochlear nerve

Question 11

What is the function of the Trochlear Nerve (CN IV)?

Answer 11

Provides motor function to the dorsal oblique extraocular muscle and rolls the globe medially.

Question 12

What is Cranial Nerve V?

Answer 12

Trigeminal nerve - Maxillary, Mandibular and Opthalmic Branches

Question 13

What is the function of the Trigeminal Nerve (CN V)?

Answer 13

Provides motor to muscles of mastication (chewing muscles) and sensory to eyelids, cornea, tongue, nasal mucosa and mouth.

Question 14

What is Cranial Nerve VI?

Answer 14

Abducens Nerve

Question 15

What is the function of the Abducens Nerve (CN VI)?

Answer 15

Provides motor functinon to the lateral rectus extraocular muscles and retractor bulbi
Observed by touching the globe and observing for refraction. Responsible for physiologic nystagmus when turning the head.

Question 16

What is Cranial Nerve VII?

Answer 16

Facial Nerve

Question 17

What is the function of the Facial Nerve (CN VII)?

Answer 17

Provides motor to muscles of facial expression (eyelids, ears, lips) and sensory to medial pinna (ear flap). Also taste to rostral tongue.
Observe for facial paralysis, deviation of nose to one side, or droopy lips
Schirmer tear test (This nerve also helps with tear production)

Question 18

What is Cranial Nerve VIII?

Answer 18

Vestibulocochlear Nerve

Question 19

What is the function of the Vestibulocochlear Nerve (CN VIII)?

Answer 19

Sensory for hearing and head position.
- A head tilt or nystagmus may suggest dysfunction of this nerve (Vestibular disease or inner ear disease)

Question 20

What is Cranial Nerve IX?

Answer 20

Glossopharyngeal Nerve

Question 21

What is the function of the Glossopharyngeal Nerve (CN IX)?

Answer 21

Innervates the pharynx for swallowing (with X). Also innervates some salivary glands and provides taste innervation from caudal tongue.
Examine by eliciting a gag reflex and observing for dysphagia (difficulty swallowing)

Question 22

What is Cranial Nerve X?

Answer 22

The Vagus Nerve

Question 23

What is the function of the Vagus Nerve (CN X)?

Answer 23

Innervates the larynx, esophagus, and pharynx. Also provides parasympathetic innervation to the heart and viscera
Tested with a gag reflex (CN IX)

Question 24

What is Cranial Nerve XI?

Answer 24

Spinal Accessory Nerve

Question 25

What is the function of the Spinal Accessory Nerve (CN XI)?

Answer 25

Innervates Cranial cervical (neck) muscles

Question 26

What is Cranial Nerve XII?

Answer 26

Hypoglossal Nerve

Question 27

What is the function of the Hypoglosseal Nerve (CN XII)?

Answer 27

Motor to the tongue (causes tongue movement)