Cranial Nerves: Functions, Exits and Reflexes

Question 1

What nerves/arteries exit through the:

Cribriform plate

Answer 1

CN I (olfactory)

Question 2

What nerves/arteries exit through the:

Optic Canal

Answer 2

CN II (optic)
Ophthalmic artery (internal carotid branch)

Question 3

What nerves/arteries exit through the:

Superior orbital fissure

Answer 3

CN III (occulomotor)
CN IV (trochlear)
CN VI (abducens)
CN V1 ( Trigeminal- opthalmic)

Question 4

What nerves/arteries exit through the:

Foramen Rotundum

Answer 4

CN V2 (trigeminal- Maxillary)

Question 5

What nerves/arteries exit through the:

Foramen Ovale

Answer 5

CN V3 (trigeminal- Mandibular)

Question 6

What nerves/arteries exit through the:

Foramen Spinosum

Answer 6

Middle Meningeal artery

Question 7

What nerves/arteries exit through the:

Internal Auditory Meatus

Answer 7

CN VII (facial)
CN VIII (vestibulocochlear)

Question 8

What nerves/arteries exit through the:

Jugular Foramen

Answer 8

CN IX (Glossopharyngeal)
CN X (Vagus)
CN XI (Accessory)
Jugular vein

Question 9

What nerves/arteries exit through the:

hypoglossal canal

Answer 9

CN XII (Hypoglossal canal)

Question 10

What nerves/arteries exit through the:

Foramen Magnum

Answer 10

Brain stem
Spinal root of XI (accessory)
Vertebral arteries

Question 11

What is the type (S/M/B) and function of:

CN I: Olfactory

Answer 11

Sensory

Smell (only CN w/o thalamic relay to cortex)

Question 12

What is the type (S/M/B) and function of:

CN II: Optic

Answer 12

Sensory

Sight

Question 13

What is the type (S/M/B) and function of:

CN III: Oculomotor

Answer 13

Motor
Eye movement (SR,IR,MR,IO)
Pupillary constriction (sphincter pupillae: edinger westphal nucleus, MUSCarinic receptors) 
Accommodation
Eyelid opening (levator palpebrae)

Question 14

What is the type (S/M/B) and function of:

CN IV: Trochlear

Answer 14

Motor
Eye Movement (SO)

Question 15

What is the type (S/M/B) and function of:

CN V: Trigeminal

Answer 15

Both
Mastication
Facial sensation (opthalmic, max, mand)
Somatosensation from anterior 2/3 tongue

Question 16

What is the type (S/M/B) and function of:

CN VI: Abducens

Answer 16

Motor
Eye movement (LR)

Question 17

What is the type (S/M/B) and function of:

CN VII: Facial

Answer 17

Both
Facial movement
TASTE from ant 2/3 of tongue (chorda tympani)
Lacrimation
Salivation (Submandibular and sublingual)
Eyelid CLOSING (orbicularis oculi)
Auditory volume modulation (stapedius)

Question 18

What is the type (S/M/B) and function of:

CN VIII: Vestibulocochlear

Answer 18

Sensory
Hearing
Balance

Question 19

What is the type (S/M/B) and function of:

CN IX: Glossopharyngeal

Answer 19

Both
Taste and sensation of post 1/3 of tongue
Swallowing
Salivation (PAROTID gland)
Monitoring carotid body and sinus chemo and baroreceptors
Elevation of pharynx/larynx (stylopharyngeus)

Question 20

What is the type (S/M/B) and function of:

CN X: Vagus

Answer 20

Both
Taste from supraglottic region
Swallowing
Soft palate elevation
Midline uvula
talking
Cough reflex
Parasympathetics to thoracoabdominal viscera
monitoring aortic arch chemo and baroreceptors

Question 21

What is the type (S/M/B) and function of:

CN XI: Accessory

Answer 21

Motor

Head turning and shoulder shrugging (SCM and trapezius)

Question 22

What is the type (S/M/B) and function of:

CN XII: Hypoglossal

Answer 22

Motor

Tongue movement

Question 23

What is the Function of the Nucleus solitarius and what CN are involved with it?

Answer 23

CN: VII, IX, X

Visceral sensory information (taste, baroreceptors, gut distention)

Question 24

What is the Function of the Nucleus ambiguus and what CN are involved with it?

Answer 24

CN: IX, X, XI (cranial portion)

Motor innervation of pharynx, larynx, upper esophagus (swallowing, palate elevation)

Question 25

What is the Function of the Dorsal Motor Nucleus and what CN are involved with it?

Answer 25

``` CN: X Sends autonomic (parasympathetic) fibers to the heart, lungs, and upper GI ```

Question 26

Name the Afferent and Efferent branch of: | The Corneal Reflex

Answer 26

Afferent: CN V1 Ophthalmic (nasociliary branch) Efferent: Bilateral CN VII (temporal branch: orbicularis oculi)

Question 27

Name the Afferent and Efferent branch of: | The Lacrimation Reflex

Answer 27

``` Afferent: CN V1 (loss of reflex does not preclude emotional tears) ``` Efferent: CN VII

Question 28

Name the Afferent and Efferent branch of: | The Jaw Jerk Reflex

Answer 28

``` Afferent: CN V3 (sensory-muscle spindle from masseter) ``` ``` Efferent: CN V3 (motor- masseter) ```

Question 29

Name the Afferent and Efferent branch of: | The Pupillary Reflex

Answer 29

Afferent: CN II Efferent: CN III

Question 30

Name the Afferent and Efferent branch of: | The Gag Reflex

Answer 30

Afferent: CN IX Efferent: CN X

Question 31

How many pairs of spinal nerves are there total and what is the distribution

Answer 31

``` 31 pairs in total 8 Cervical (all exit above: C8 above T1) 12 Thoracic (all below) 5 Lumbar 5 Sacral 1 Coccygeal ```

Question 32

Where does the spinal cord end on adults and where do you do a lumbar puncture?

Answer 32

Spinal cord ends: L1-L2 lower border | Do lumbar puncture: L3-L4 or L4-L5 (level of cauda equina) (use illiac crest as guide)