Cranial Nerves

Question 1

List the Cranial Nerves

Answer 1

1 Olfactory
2 Optic
3 Oculomotor
4 Trochlear
5 Trigeminal
6 Abducens
7 Facial,
8 Vestibulocochlear
9 Glossopharyngeal
10 Vagus
11 Accessory
12 Hypoglossal

Use this mnemonic to help you remember the order: On Old Olympus Towering Tops A Fat Vested German Viewed A Hop

Question 2

Name, Function (Sensory, Motor, Both), and Monitoring Details for CN I

Answer 2

Olfactory (S)

Sense of Smell

Cannot be monitored

Question 3

Name, Function (Sensory, Motor, Both), and Monitoring Details for CN II

Answer 3

Optic (S)

Vision

Visual Evoked Potentials

Question 4

Name, Function (Sensory, Motor, Both), and Monitoring Details for CN III

Answer 4

Oculomotor (M)

Eye Movement, Inferior Rectus (Under eye)

EMG/tcMEP

Question 5

Name, Function (Sensory, Motor, Both), and Monitoring Details for CN IV

Answer 5

Trochlear (M)

Eye Movement, Superior Oblique Muscle (Over eye)

EMG/tcMEP

Question 6

Name, Function (Sensory, Motor, Both), and Monitoring Details for CN V

Answer 6

Trigeminal (B)
Three divisions of nerve: V1 Ophthalmic, V2 Maxillary, V3 Mandibular

Motor portion: Muscles of Mastication
Sensory portion: Convey Sensations of Touch, Pain, and Temperature

EMG, tcMEP: Masseter and Temporalis

Question 7

Name, Function (Sensory, Motor, Both), and Monitoring Details for CN VI

Answer 7

Abducens (M)

Eye Movement, Lateral Rectus (Lateral to eye)

EMG/tcMEP

Question 8

Name, Function (Sensory, Motor, Both), and Monitoring Details for CN VII

Answer 8

Facial (B)
Five Branches: Temporal, Zygomatic, Buccal, Marginal Mandibular, Cervical
(Use this mnemonic to help you remember: To Zanzibar By Motor Car)

Motor portion: Facial Expressions
Sensory portion: Anterior 2/3 of Tongue, Floor of Mouth/Anterior Palate

EMG/tcMEP

Question 9

What are the Five Branches of CN VII and what muscles are monitored for each branch?

Answer 9

Temporal Branch / Frontalis Muscle
Zygomatic Branch / Orbicularis Oculi Muscle
Buccal Branch / Orbicularis Oris Muscle
Marginal Mandibular Branch / Mentalis Muscle
Cervical / Platysma Muscle

Note: Branches Pass through Parotid Gland

Question 10

Name, Function (Sensory, Motor, Both), and Monitoring Details for CN VIII

Answer 10

Vestibulocochlear (S)

Balance, Maintenance of Body Position and Proprioception (Vestibular)
Sense of Hearing (Cochlear),

BAEP

Question 11

Name, Function (Sensory, Motor, Both), and Monitoring Details for CN IX

Answer 11

Glossopharyngeal (B)

Motor portion: Assist in swallowing
Sensory portion: Posterior 1/3 tongue

Soft Palate

EMG/tcMEP

Question 12

Name, Function (Sensory, Motor, Both), and Monitoring Details for CN X

Answer 12

Vagus (B)

Motor portion: Pharynx and Larynx control
Sensory portion: Sensory function of larynx

EMG/tcMEP Vocalis via Recurrent Laryngeal Nerve Monitoring

Question 13

Name, Function (Sensory, Motor, Both), and Monitoring Details for CN XI

Answer 13

Accessory (M)

Shoulder Movement, Trapezius and Sternocleidomastoid

EMG/tcMEP

Question 14

Name, Function (Sensory, Motor, Both), and Monitoring Details for CN XII

Answer 14

Hypoglossal (M)

Speech and Swallowing
Lateral aspect of the anterior 1/3 of the Ipsilateral Tongue

EMG/tcMEP

Question 15

A cavernous sinus surgery involves what cranial nerves?

Answer 15

CN III (Oculomotor)
CN IV (Trochlear) 
CN VI (Abducens)

All of these nerves pass through the cavernous sinus.

Question 16

A skull base (clival) surgery involves what cranial nerves?

Answer 16

CN V (Trigeminal)
CN VII (Facial)
CN VIII (Vestibulocochlear/Auditory)

(Skull Base surgery)
Clivus = Bone at base of skull, tumors sometimes grow here

Question 17

A Microvascular Decompression surgery for treatment of Trigeminal Neuralgia involves what cranial nerves?

Answer 17

CN V (Trigeminal)
CN VII (Facial)
CN VIII (Auditory)

MVD involves opening the skull (craniotomy) and inserting a sponge between the nerve and offending artery triggering the pain signals.

Question 18

Cerebellopontine (CP) Angle (e.g. acoustic neuroma) lesion would affect what CN?

Answer 18

CN V (Trigeminal)
CN VII (Facial)
CN VIII (Auditory)

(CN V-XII if lesion is large enough)

Question 19

What is Tic Douloureux?

Answer 19

We know this as Trigeminal Neuralgia. It comes from the French phrase Tic Douloureux which literally means “a painful tic”

Compression of CN V usually caused by Superior Cerebellar Artery (SCA) which results in intolerable facial pain

Monitored: 
CN V (Trigeminal)
CN VII (Facial)
CN VIII (Auditory)

Question 20

What is Hemifacial Spasm?

Answer 20

Hemifacial spasm is a nervous system disorder in which the muscles on one side of your face twitch involuntarily. Hemifacial spasm is most often caused by a blood vessel touching or pulsating against a facial nerve. It may also be caused by a facial nerve injury or a tumor.

Question 21

What is Glossopharyngeal Neuralgia?

Answer 21

Irritation of the ninth cranial nerve causing pain at the back of the throat (rare)

Question 22

What does the Pons control?

Answer 22

The pons relays information about motor function, sensation, eye movement, hearing, taste, and more.

The middle four cranial nerves originate from the pons:

• trigeminal nerve (CN V)
• abducens nerve (CN VI)
• facial nerve (CN VII)
• vestibulocochlear nerve (CN VIII)

Question 23

What does the Medulla control?

Answer 23

The medulla oblongata plays a critical role in transmitting signals between the spinal cord and the higher parts of the brain and in controlling autonomic activities, such as heartbeat and respiration.

The final four cranial nerves originate from the medulla oblongata:

• glossopharyngeal nerve (CN IX)
• vagus nerve (CN X)
• accessory nerve (CN XI)
• hypoglossal nerve (CN XII)