Cranial Nerves

Question 1

Name the cranial nerves in order.

Answer 1

Olfactory 
Optic
Occulomotor 
Trochlear 
Trigeminal 
Abducens 
Facial 
Vestibulocochlear 
Glossopharyngeal 
Vagus 
Spinal Accessory 
Hypoglossal

Question 2

Where does the olfactory nerve arise and leave the cranial cavity?

Answer 2

Cerebrum

Cribiform plate.

Question 3

Where does the optic nerve arise and leave the cranial cavity?

Answer 3

Cerebrum

Optic canal.

Question 4

Where does the occulomotor nerve arise and leave the cranial cavity?

Answer 4

Midbrain-pontine junction

Superior orbital fissure.

Question 5

Where does the trochlear nerve arise and leave the cranial cavity?

Answer 5

Midbrain

Superior orbital fissure.

Question 6

Where does the trigeminal nerve arise and leave the cranial cavity?

Answer 6

Pons
Ophthalamic V1 - Superior Orbital Fissure
Maxillary V2 - Foramen Rotundum
Mandibular V3 - Foramen Ovale

Question 7

Where does the abducens nerve arise and leave the cranial cavity?

Answer 7

Pontine-medullary junction

Superior orbital fissure.

Question 8

Where does the facial nerve arise and leave the cranial cavity?

Answer 8

Pontine-medullary junction

Internal acoustic meatus.

Question 9

Where does the vestibulococchlear nerve arise and leave the cranial cavity?

Answer 9

Pontine-medullary junction

Internal acoustic meatus.

Question 10

Where does the glossopharyngeal nerve arise and leave the cranial cavity?

Answer 10

Medulla posterior to the olive

Jugular foramen.

Question 11

Where does the vagus nerve arise and leave the cranial cavity?

Answer 11

Medulla posterior to the olive

Jugular foramen.

Question 12

Where does the spinal accessory nerve arise and leave the cranial cavity?

Answer 12

Medulla oblongata posterior to the olive

Jugular foramen.

Question 13

Where does the hypoglossal nerve arise and leave the cranial cavity?

Answer 13

Medulla anterior to the olive

Hypoglossal canal.

Question 14

How do you test the olfactory nerve?

Answer 14

Ask patient to sniff something familiar e.g. coffee or toothpaste. Ensure it isnt an irritant (as this stimulates V1 also). Check each nostril.

Question 15

How do you test the optic nerve?

Answer 15

Test visual fields by asking patient to look at you whilst wiggling finger in 4 quadrants.
Check pupillary reflex.

Question 16

How do you test the occulomotor, trochlear and abducens nerve?

Answer 16

Draw a H shape.
Vertical - superior/inferior rectus and superior and inferior oblique muscles.
Horizontal - medial and lateral rectus muscles.

Question 17

How do you test the trigeminal nerve?

Answer 17

Sensory: Close eyes and toch the 3 areas innervated by branches of V - forehead, cheeks and chin.
Motor: Ask patient to clench jaw and palpate masseter and temporalis. Check pterygoids by opening mouth against resistance. Jaw should not deviate.

Question 18

How do you test the facial nerve?

Answer 18

Ask patient to perform movements.

e.g. show teeth, raise eyebrows, keep eyes closed against resistance, puff cheeks against resistance, purse lips.

Question 19

How do you test the vestibulococchlear nerve?

Answer 19

Rinnes test: Tuning fork against mastoid process and once it stops vibrating next to the external ear and ask if they can still hear it.
Webers test: Tuning fork is placed in centre of forehead and ask which ear it is louder in. Should be the same.
Neural deafness heard louder in the intact ear.
Conductive heard louder in the affected ear.

Turning test for vestibular: Ask patient to march on spot with arms outstretched and eyes closed. If lesion, patient will turn towards the side the lesion is on.

Question 20

How do you test the glossopharyngeal nerve?

Answer 20

Check gag reflex.
Ensure no dysphagia.
Ask them to cough and swallow.

Question 21

How do you test the vagus nerve?

Answer 21

Ask patient to speak to assess larynx/pharynx muscles.

Check uvula is central when patient says ahhhhh…

Question 22

How do you test the spinal accessory nerve?

Answer 22

Check trapezius and SCM.

Should be able to shrug shoulders and turn the head against resistance.

Question 23

How do you test the hypoglossal nerve?

Answer 23

Stick out tongue and move it side to side. Check muscles of the tongue are symmetrical.