Cranial Nerve 1-6

Question 1

Are the cranial nerves part of the CNS or PNS?

Answer 1

PNS

Question 2

How many Cranial nerves are there?

Answer 2

12 Pairs

Question 3

Which structures form the brainstem?

Answer 3

Midbrain, pons and medulla

Question 4

What is the first cranial nerve and what type of nerve is it?

Answer 4

Olfactory nerve, special sensory nerve for smell

Question 5

Name 1 thing that can cause anosmia?

Answer 5

Head injury

Question 6

What is the second cranial nerve and what kind of nerve is it ?

Answer 6

Optic nerve, special sensory

Question 7

At what structure does mixing of sensory fibres from the left and right optic nerve occur?

Answer 7

Optic chiasm

Question 8

How can raised intracranial pressure be seen in the eyes?

Answer 8

Optic nerves carry extension of the meninges, so a swollen optic disc(papillodema) can be seen with an opthalmoscope

Question 9

Why are the first 2 nerves not true cranial nerves?

Answer 9

They do not arise from the brainstem but are extensions of the brain itself

Question 10

What is the third Cranial nerve and what kind of nerve is it?

Answer 10

Oculomotor nerve, motor and autonomic parasympathetic innervation

Question 11

Name 3 functions of the oculomotor nerve

Answer 11

Muscles that move the eyeball, muscles of the eyelid and innervates sphincter pupillae muscle (constrict pupil)

Question 12

Why is the oculomotor nerve vulnerable to compression and what does this cause?

Answer 12

When there is raised intracranial pressure the nerve is compressed between the tentorium cerebelli and the temporal lobe so the parasympathetic fibres that constrict pupils are affected, pupils can blow (dilate)

Question 13

Name 2 things pathology of the oculomotor nerve can cause

Answer 13

Pupillary dilation and double vision (diplopia)

Question 14

What is the fourth cranial nerve and what kind of nerve is it?

Answer 14

Trochlear nerve, motor innervation

Question 15

What is the function of the trochlear nerve?

Answer 15

Innervates one of the muscles that moves the eyeball

Question 16

Which nerve has the longest intracranial course of any of the cranial nerves?

Answer 16

Trochlear nerve

Question 17

What is the fifth cranial nerve and what kind of nerve is it?

Answer 17

Trigeminal nerve, General sensory and motor innervation

Question 18

Which branch of the trigeminal nerve has motor innervation?

Answer 18

Mandibular

Question 19

How do we test the trigeminal nerve?

Answer 19

Sensation over the dermatomes, muscles of mastication and corneal reflex

Question 20

Name 3 branches of the Opthalmic division of the trigeminal nerve

Answer 20

Frontal, lacrimal and nasociliary

Question 21

Name 2 branches of the maxillary division of the trigeminal nerve

Answer 21

Infraorbital and superior alveolar nerves

Question 22

Name 3 branches of the mandibular division of the trigeminal nerve

Answer 22

Inferior alveolar, auriculotemporal and lingual

Question 23

What is the 6th Cranial and what kind of nerve is it?

Answer 23

Abducens nerve, motor nerve

Question 24

Where does the Abducens nerve originate and what structure of the skull does it pass through?

Answer 24

Pontomedullary junction, passes through the superior orbital fissure

Question 25

What does the Abducens nerve do?

Answer 25

Innervates 1 muscle that moves the eye

Question 26

Why is the Abducens nerve susceptible to increased intracranial pressure ?

Answer 26

The nerve passes under the pons toward the cavernous sinus and can be stretched