Cranial nerves function

Question 1

Function of Olfactory nerve?

Answer 1

Special sense of smell

Question 2

Where does Cr.N I exit the skull?

Answer 2

Cribriform plate of the ethmoid bone.

Question 3

What is the function of Cr.N II?

Answer 3

The optic nerve is responsible for vision.

Question 4

Where does the Optic nerve exit the skull?

Answer 4

Cr.N II exits through the optic canal

Question 5

What three nerves contribute to eye movement?

Answer 5

Cr.N III- oculomotor (innervates all but two of the extra-ocular eye muscles)
Cr.N IV- trochlear, this innervates the superior oblique muscle and is therefore responsible for a down and outwards movement.
Cr.N VI- abducens innervates the lateral rectus muscle, this is responsible for the abduction of the eye.

Question 6

Which nerves exit the skull through the superior orbital fissure?

Answer 6

Oculomotor - III
Trochlear- IV
Ophthalmic branch of the trigeminal - V1
Abducens - VI

Question 7

What is the function of the Trigeminal nerve?

Answer 7

It is the sensory supply to the face through its three branches (including the ophthalmic branch being the sensory innervation for the eye).
It also supplies motor function to the muscles of mastication.

Question 8

What is the function of Cr.N VII?

Answer 8

The facial nerve supplies the muscles of facial expression. It also innervates special sense of taste from the anterior 2/3 of the tongue and supplies the submandibular and sublingual glands.

Question 9

Where does the Maxillary branch of the Trigeminal leave the skull?

Answer 9

The foramen rotundum

Question 10

Where does Cr.N V3 exit?

Answer 10

The foramen ovale.

Question 11

Where does the Facial nerve leave the skull?

Answer 11

Cr.N VII exits via the internal auditory meatus and then through the facial canal in the temporal bone and out of the stylomastoid foramen.
Facial supplies general sense in the ear.

The vestibulocochlear also exits via the internal auditory meatus.

Question 12

What is Cr.N VIII?

Answer 12

Vestibulocochlear nerve.

Question 13

What nerves are responsible for movement of the pharyngeal muscles?

Answer 13

The Glossopharyngeal - Cr.N IX
Vagus nerve- Cr.N X

The glossopharyngeal is also special sensory from the posterior 1/3 tongue.And general sensory from the ear.

Question 14

Which nerves leave through Jugular foramen?

Answer 14

Glossopharyngeal - Cr.N IX
Vagus- Cr.N X
Accessory- Cr.N XI

Question 15

Where does Cr.N XII exit the skull?

Answer 15

The hypoglossal nerve leaves through the hypoglossal canal.

Question 16

What is the function of the accessory nerve?

Answer 16

It innervates the sternocleidomastoid muscle and the trapezius muscle.

Question 17

What is the function of the hypoglossal nerve?

Answer 17

It supplies motor innervation to the tongue.

Question 18

What causes pupillary constriction?

Answer 18

Oculomotor - Cr.N III

Question 19

What innervates the parotid gland?

Answer 19

Cr. N IX- glossopharyneal, this stimulates salivation

Question 20

What innervates salivation on the submandibular and sublingual glands?

Answer 20

Cr.N VII - facial nerve

Question 21

What near is lacrimation innervated by?

Answer 21

The facial nerve- Cr.N VII

Question 22

Where are the nuclei of cranial nerves III and IV?

Answer 22

They are in the midbrain

Question 23

Which cranial nerves have their nuclei in the Pons?

Answer 23

V-trigeminal
VI-abducens
VII- facial

Question 24

Where is the nuclei of the vestibulocochlear nerve?

Answer 24

Nuclei of the VIII nerve is at the Ponto-medullary junction

Question 25

Which nerves have their nuclei in the Medulla?

Answer 25

IX- Glossopharyngeal
X- vagus
XI- Accessory
XII- Hypoglossal

Question 26

What is Bell’s palsy?

Answer 26

Idiopathic paralysis of the facial nerve.

Question 27

How do you treat Bell’s palsy?

Answer 27

Steroids and sometimes aciclovir

Question 28

What are the symptoms of vestibular neuronitis?

Answer 28

Sudden onset
Disabling vertigo
Vomiting
Gradual recovery

Question 29

What is the difference between Bulbar palsy and pseudobulbar palsy?

Answer 29

Bulbar palsy is a LMN problem

and Pseudobulbar palsy is an UMN problem.

Question 30

What is pseudobulbar palsy and it’s symptoms?

Answer 30

Bilateral UMN lesions e.g. in vascular lesions of both internal capsules

• dysarthria
• dysphonia (problem with volume of speech/hoarsness)
• dysphagia
• spastic, immobile tongue
• brisk jaw jerk
• brisk gag reflex

Question 31

What is bulbar palsy and what are it’s symptoms?

Answer 31

Bilateral LMN lesions affecting IX - XII

• wasted, fasciculating tongue
• dysarthria
• dysphonia
• dysphagia