4 - Peripheral Distribution of Cranial Nerves (I + II)

Question 1

Name the 12 cranial nerves in order

Answer 1

Olfactory, Optic, Oculomotor, Trochlear, Trigeminal. Abducens, Facial, Vestibular, Glossopharyngeal, Vagus, Accessory, Hypoglossal

Question 2

Label the 12 cranial nerves on this diagram

https://www.purposegames.com/images/games/background/48/48380.jpg

Answer 2

https://s-media-cache-ak0.pinimg.com/736x/f5/a8/c2/f5a8c2e36ed7f537b036c796c1d790c4.jpg

Question 3

What are the three cranial nerves which innervate the extraocular muscles?

Answer 3

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

Question 4

What are the extraocular muscles?

Answer 4

Superior, inferior, lateral and medial rectus muscles

Superior and inferior oblique muscles

Question 5

What is the origin of the the rectus muscles?

Answer 5

Common tendinous ring

Question 6

Where do the rectus muscles attach?

Answer 6

Sclera just anterior to the equator of the eye

Question 7

Where do the oblique muscles attach?

Answer 7

Superior oblique - Common tendinous ring to the trochlear and then inserts posterior to the equator
Inferior oblique - Medial floor of the orbit to the posterolateral surface of the eyeball

Question 8

What is the action of the superior and inferior oblique?

Answer 8

Superior oblique - Depress the eye

Inferior oblique - Elevate the eye

Question 9

http://www.netterimages.com/images/vpv/000/000/007/7846-0550x0475.jpg

Label the diagram of the extrinsic eye muscles

Answer 9

http://anatomybody101.com/wp-content/uploads/2015/11/eye-muscles-anatomy-extrinsic-eye-muscles-rectus-trochlea-oblique-medial-superior-lateral-common-tendinous-ring.jpg

Question 10

What nerve innervates the

a. Superior, inferior and medial rectus muscle?
b. Lateral rectus muscle?
c. Superior oblique muscle?
d. Inferior oblique muscle?

Answer 10

What nerve innervates the
	a. Superior, inferior and medial rectus muscle?
	CN III - Oculomotor 
	b. Lateral rectus muscle?
CN VI - Abducens 
	c. Superior oblique muscle?
	CN IV - Trochlear 
	d. Inferior oblique muscle?
	CN III - Oculomotor

Question 11

What is the function of the levator palpebrae superioris?
What nerve is it innervated by?
Where does it originate?

Answer 11

• To lift up the eyelid
• CN III - Oculomotor
• Common tendinous ring

Question 12

Where is the lacrimal gland and its function?

Answer 12

Top lateral corner of the orbit and is responsible for fluid over the eye

Question 13

Which nerve travels through the

• Optic Canal
• Superior Orbital Fissure

Answer 13

• Optic nerve

- Oculomotor, Abducens, Trochlea and V1

Question 14

Label the nerves of the orbit

https://www.netterimages.com/images/vpv/000/000/015/15300-0550x0475.jpg

Answer 14

https://netterimages.com/images/vpv/000/000/060/60550-0550x0475.jpg

Question 15

Where do the oculomotor presynaptic parasympathetic fibres travel to?

Answer 15

Ciliary Ganglion

Question 16

What does the oculomotor postsynaptic parasympathetic innervate?

Answer 16

Sphincter pupillae and ciliary muscle

Question 17

Where do the sympathetic fibres of the oculomotor nerve pass through and innervate?

Answer 17

Pass through the ciliary ganglion from internal carotid plexus - innervate dilator pupillae and blood vessels of the eye

Question 18

What is the primary action of each rectus and oblique muscle?

Answer 18

Medial rectus - Adduction
Lateral rectus - Abduction
Superior rectus and Inferior oblique - elevate the eye
Inferior rectus and Superior oblique - depress the eye

Question 19

How do you test the nerves of the extraocular muscles?

Answer 19

Ask an individual to move their eyes up and in (superior rectus, inferior oblique and medial rectus)
If they have to abduct their eye first - medial rectus can’t be used

Question 20

What are the symptoms of oculomotor palsy?

Answer 20

All muscles except superior oblique and lateral rectus are paralysed
Pulls eye into a down and out position
Ptosis - Eyelid semi-closed
Dilated pupil - oculomotor brings parasympathetic fibres

Question 21

What are the symptoms of trochlear palsy? What would you see on a patient?

Answer 21

Superior oblique paralysed
Prevents abduction and depression
Eye elevates and adducts
Tilts neck - so eyes are at the same angle
Complain of neck pain or inability to walk down stairs

Question 22

What are the symptoms of Abducens palsy? What would you see on a patient?

Answer 22

Lateral rectus paralysed
Affected eye cannot abduct
Eyes appear normal when looking forward however cannot look to the side

Question 23

What are the symptoms of horner’s syndrome? What would you see on a patient?

Answer 23

Lack of sympathetic supply to the eye
Pinned pupil due to unopposed parasympathetic activity
Ptosis - lack of tone

Question 24

What is Bell’s Palsy?

Answer 24

Facial muscle paralysis LMN

Cornea is at risk of drying out, muscles of upper face are bilaterally innervated by upper motor neurones

Question 25

What are the contents of the Carotid sheath?

Answer 25

Common carotid artery
Internal carotid artery
Internal Jugular Vein
Vagus nerve

Question 26

How would you test the trochlear nerve?

Answer 26

Shine a pen torch into one eye and check that the pupils on both sides constrict

Question 27

What happens if you damage your trochlear (IV) nerve?

Answer 27

Paralysis of the superior oblique eye muscle
Leads to unopposed extortion in one eye
Patient’s head tilts away from the site of the legion

Question 28

What are the 3 sensory branches of the trigeminal (V) nerve?

Answer 28

V1 - Opthalmic
V2 - Maxillary
V3 - Mandibular

Question 29

What happens when you damage the trigeminal (V) nerve?

Answer 29

By pressure aneurysm
Paralysis in muscles of mastication
Loss of corneal reflex and sensation in face
3rd molar extraction - can damage lingual nerve - loss of sensation to the tongue and reduces saliva
- Due to loss of parasympathetic supply to the submandibular and sublingual salivary glands

Question 30

What happens if you damage the hypoglossal nerve (XII)?

Answer 30

Paralysis to ipsilateral half of the tongue

Tongue deviates towards the side of the lesion

Question 31

** Important
Fill in the table on the google docs
- The nerve type, function and where it exits the skull for all 12 cranial nerves

Answer 31

Check the google docs