Peripheral organisation of cranial nerves

Question 1

Name cranial nerve I

Answer 1

Olfactory nerve

Question 2

Where in CNI derived from?

Answer 2

The olfactory bulb, which sits just under the frontal cortex over the frontal bone and ethmoid bone

Question 3

Function of CN I?

Answer 3

Sensory for smell

Question 4

Name CN II

Answer 4

Optic nerve

Question 5

What foramen does CN I pass through?

Answer 5

Olfactory foramen

Question 6

What is the optic canal a foramen for?

Answer 6

Optic nerve and ophthalmic artery

Question 7

What passes through the superior orbital fissure?

Answer 7

Cranial nerves III,IV, VI and the first part of V

Ophthalmic vein

Question 8

Where do the extraocular eye muscles attach?

Answer 8

The outside of the eye

Question 9

What are the 6 extraocular eye muscles?

Answer 9

4 rectus muscles: superior, inferior, medial and lateral

2 oblique muscles: superior and inferior

Question 10

Where do the four rectus muscles originate and attach?

Answer 10

Originate from common tendinous ring and attach to the sclera, anterior to the equator of the eye

Question 11

Describe the passage and attachment of the superior oblique muscle

Answer 11

Travels up the medial side of eye and goes to trochlea which is a pulley. Goes through pulley to insert in sclera posterior to equator

Question 12

Where does the inferior oblique muscle emerge from and insert into?

Answer 12

Emerges from maxilla inserts into sclera posterior to equator of the eye

Question 13

What is the name of CN III?

Answer 13

Occulomotor

Question 14

Which two muscles does the occulomotor nerve NOT supply

Answer 14

Superior oblique and lateral rectus

Question 15

What cranial nerves supply superior oblique and lateral rectus?

Answer 15

Superior oblique= IV

Lateral rectus= VI

Question 16

Where do oculomotor parasympathetic fibres supply?

Answer 16

Pupil/ intrinsic muscles of the eye

Oculomotor parasympathetic fibres travel to ciliary ganglion

Question 17

What is the action of medial rectus?

Answer 17

Adducts (turns eye in)

Question 18

What is the action of lateral rectus?

Answer 18

Abduct (turns eye out)

Question 19

What is the action of superior rectus?

Answer 19

Elevation and adduction

Question 20

What is the action of inferior rectus?

Answer 20

Depression

Question 21

What is the action of superior oblique

Answer 21

Intorts

Question 22

What is the action of inferior oblique

Answer 22

Extorts

Question 23

Which muscles aid superior rectus in adduction and elevation

Answer 23

Inferior oblique and medial rectus

Question 24

What would you see in oculomotor nerve palsy?

Answer 24

The only muscle that still has tone is superior oblique and lateral rectus. Eye will be down and out. Also constant dilation due to unopposed sympathetic innervation

Question 25

What would you see in trochlea nerve palsy?

Answer 25

Paralyses the superior oblique. Right eye is up and in. Patients attempt to minimise this by tilting head so could complain of neck pain.

Question 26

What would you see in abducens palsy?

Answer 26

Loss of ability to abduct eye. Paralysis of lateral rectus.

Question 27

What is the name of CN V?

Answer 27

Trigeminal nerve

Question 28

What are the three divisions of the trigeminal nerve?

Answer 28

Ophthalmic, maxillary, mandibular

Question 29

What does CN V supply (generally)

Answer 29

Sensory nerve of the face. Supplies skin and deeper structure such as mucous membrane and anterior 2/3 of the tongue

Question 30

What does the ophthalmic nerve branch into?

Answer 30

Lacrimal, frontal and nasociliary

Question 31

What does lacrimal nerve supply?

Answer 31

Lacrimal glands

Question 32

What does the frontal nerve supply?

Answer 32

Forehead

Question 33

Is the maxillary sensory, motor or mixed?

Answer 33

Sensory

Question 34

What do the branches of maxillary nerve supply?

Answer 34

Superior alveolar branches go to superior dentition Infraorbital opens up onto face via infraorbital foramen Palatine goes to palate

Question 35

What is the mandibular nerve motor to?

Answer 35

Muscles of mastication

Question 36

What are the 2 main sensory branches of the mandibular nerve?

Answer 36

Inferior alveolar and lingual

Question 37

What does the inferior alveolar supply?

Answer 37

Sensory to lower dentition

Question 38

What does the lingual nerve supply?

Answer 38

Sensory to anterior 2/3 of the tongue

Question 39

What is the name of CN VII

Answer 39

Facial nerve

Question 40

What is the motor function of the facial nerve?

Answer 40

Superficial muscles of facial expression

Question 41

What is the chorda tympani?

Answer 41

Parasympathetic branch of facial nerve, travels with 3. Special sensory related to taste on anterior 2/3 of tongue

Question 42

What is the greater petrosal nerve?

Answer 42

Higher parasympathetic branch of facial nerve- passes through parotid but does not supply

Question 43

What is the name CN IX?

Answer 43

Glossopharyngeal

Question 44

Where does CN IX exit?

Answer 44

jugular foramen

Question 45

Function of glossopharyngeal nerve (3)

Answer 45

Parasympathetic to parotid gland Special sensory to back of tongue Sensory to the oropharynx

Question 46

What is the afferent and efferent to gag reflex

Answer 46

``` Afferent= glossopharyngeal Efferent= vagus ```

Question 47

How does the vagus nerve run down the neck?

Answer 47

In the carotid sheath | Between medial carotid arteries and interal jugular veins

Question 48

What is the name of CN XI?

Answer 48

Spinal accesory nerve

Question 49

Where does CN XI emerge?

Answer 49

Cranium not the brain

Question 50

Where do nerve rootlets of CN XI arise from?

Answer 50

C5-C6

Question 51

How do nerve rootlets travel up to brain?

Answer 51

Form a nerve and ascend cranial cavity via foramen magnum. Exit through jugular foramen

Question 52

What does CN XI supply?

Answer 52

Somatic motor fibres to accesory muscles of breathing (sternocleidomastoid and trapezius)

Question 53

What is the name of CN XII?

Answer 53

Hypoglossal

Question 54

How is the hypoglossal nerve formed?

Answer 54

Rootlets from the medulla. Leaves the hypoglossal canal. Joined by C1 and C2 which go into infrahyoid muscles.