Cranial Nerves

Question 1

What fibre type does the Olfactory Nerve carry?

Answer 1

SVA - smell

Question 2

What is the olfactory tract/bulb?

Answer 2

The olfactory tract is the structure which runs along the inferior surface of the frontal lobe, the olfactory bulb is a swelling at the end of this where 1st order neurones synapse with 2nd order neurones.

Question 3

Where does CN I originate?

Answer 3

It is an extension of forebrain,

Question 4

What fibre types are carried by the optic nerve?

Answer 4

SSA - special sense (vision) not associated with viscera.

Question 5

What fibre types does the Occulomotor nerve have?

Answer 5

GSE to muscles

GVE to autonomically supplied muscles

Question 6

Describe the origin of partial ptosis.

Answer 6

The eye lid is supplied by levator palpebrae Superioris - innervated by CN III however a small part called the superior tarsal muscle is innervated by sympathetic fibres, if innervation is lost to this structure then partial ptosis occurs,

Question 7

Through which structures does the Occulomotor nerve pass on its route to the orbit?

Answer 7

Cavernous sinus and medial aspect of superior orbital fissure.

Question 8

Which nerve originates from the dorsal aspect of the brainstem?

Answer 8

Trochlea nerve

Question 9

What fibres are carried by the trochlea nerve?

Answer 9

GSE to Superior oblique

Question 10

What fibres are carried by the Abducens nerve?

Answer 10

GSE to lateral rectus

Question 11

Where in the superior orbital fissure do Nerves to the orbit run?

Answer 11

Medial - Occulomotor, Abducens, nasocilliary

Lateral - frontal, trochlea, lacrimal

Question 12

Where does the Abducens nerve originate?

Answer 12

From the pontomedullary junction.

Question 13

What true trigeminal fibres run in the trigeminal nerve?

Answer 13

SVE to muscles of mastication

GSA to face and scalp

Question 14

What structures are supplied by facial nerve fibres? What fibre types supply these?

Answer 14

SVA - taste to anterior 1/3 of the tongue
SVE - muscles of facial expression
GVE - submandibular/ sublingual salivary glands, accessory palatine salivary glands, nasal glands and lacrimal glands

Question 15

Where are the cell bodies of sensory fibres of the facial nerve located?

Answer 15

Geniculate ganglion in the petrous part of the temporal bone.

Question 16

Where does the facial nerve exit the cranial cavity?

Answer 16

Internal acoustic meatus

Question 17

Besides the muscles of facial expression, which other muscles are supplied by the facial nerve?

Answer 17

Stapedius, posterior belly of digastric, stylohyoid.

Question 18

What fibres run in the vestibulocochlear nerve?

Answer 18

SSA - Auditory

Question 19

Describe the course of the vestibulocochlear nerve.

Answer 19

This nerve emerges from the cerebllopontine angle and runs laterally into the internal acoustic meatus. In the lateral aspect of this meatus it divides into 2 Nerves - vestibular and cochlea.

Question 20

How many fibre types does the glossopharyngeal nerve contain?

Answer 20

5
SVA to posterior tongue
GSA to posterior tongue, pharynx and ear
SVE to stylopharyngeus
GVE to parotid gland
GVA to carotid body and sinus

Question 21

Which nerve supplies stylopharyngeus? What is the fibre type?

Answer 21

Glossopharyngeal

SVE

Question 22

Which nerve supplies the carotid body and sinus?

Answer 22

Glossopharyngeal

GVA

Question 23

How does the glossopharyngeal nerve exit the cranial cavity?

Answer 23

Through the jugular foramen

Question 24

What are the main structures supplied by the vagus nerve?

Answer 24

Motor to the muscles of pharynx and larynx, sensory supply to external acoustic meatus, taste to vallecula and epiglottis, parasympathetic supply to thorax and abdomen and visceral sensation to thorax and abdomen,

Question 25

What fibre types are contained in the vagus nerve and what do these supply?

Answer 25

GVA - stretch to larynx and chemoception/ stretch to thorax and abdomen SVA to vallecula and epiglottis SVE - muscles of the larynx and pharynx GVE - parasympathetic supply to thorax/abdomen GSA - dura and External acoustic meatus

Question 26

Which structures are supplied by SVE fibres of CN X?

Answer 26

Muscles of pharynx and larynx, palatoglossus, levator veli palatini

Question 27

With what structures in the neck does the vagus nerve run?

Answer 27

Runs within the carotid sheath with the internal jugular vein and the internal carotid artery.

Question 28

How does CN X exit the cranial cavity?

Answer 28

Via the jugular foramen

Question 29

Where in the brainstem does the vagus nerve arise?

Answer 29

Dorsolateral sulcus of the medulla

Question 30

Describe innervation of the SCM and Trapezius muscles.

Answer 30

These muscles receive the majority of their motor supply from the accessory nerve however there is some debate as to whether cervical plexus fibres contribute to this. Proprioception supply to these muscles is by the cervical plexus.

Question 31

What fibres are contained within the accessory nerve?.

Answer 31

SVE to SCM and Trapezius

Question 32

Describe the course of the the spinal part of the accessory nerve.

Answer 32

This originates from the cervical spine and passes into the cranial cavity via foramen magnum and joins with the cranial part of the nerve. This then e it’s the cranial cavity through the jugular foramen.

Question 33

What does the hypoglossal nerve supply?

Answer 33

Motor to muscles of the tongue. GSE fibres.

Question 34

Where does the hypoglossal nerve arise?

Answer 34

Anteriorlateral aspect of the medulla.

Question 35

Where does the hypoglossal nerve exit the cranial cavity?

Answer 35

Hypoglossal canal found on the lateral aspect of foramen magnum.

Question 36

Which nerves contain SVA?

Answer 36

I, VII, IX, X

Question 37

Which nerves contain SSA?

Answer 37

II, VIII

Question 38

Which nerves contain GSA?

Answer 38

V, VII, IX, X

Question 39

Which nerves contain GVA?

Answer 39

VII, IX, X

Question 40

Which nerves contain a SVE?

Answer 40

V, VII, IX, X

Question 41

Which nerves contain GSE?

Answer 41

III, IV, VI, XII

Question 42

Which nerves contain GVE?

Answer 42

III, VII, IX, X