Cranial Nerves

Question 1

Which CN is in the ciribiform plate?

Answer 1

Olfactory (CN I)

Question 2

Which CN is within the optic canal?

Answer 2

CN II (optic)

Question 3

Which nerves pass through the superior orbital fissure?

Answer 3

CN III (oculomotor), IV (trochlear), V1 (opthalamic division of trigeminal), VI (abducens)

Question 4

Which nerves pass through the foramen rotundum?

Answer 4

CN V2 (maxillary division of trigeminal)

Question 5

Which CN pass through the foramen ovale?

Answer 5

CN V3 (mandibular division of trigeminal)

Question 6

Which nerves pass through the internal acoustic meatus?

Answer 6

CN VII (facial) and CN VIII (vestibulocochlear)

Question 7

Which CN pass through the jugular foramen?

Answer 7

CN IX (glossopharyngeal), X (vagus), IX (accessory)

Question 8

Which CN passes though the hypoglossal canal?

Answer 8

CN XII (hypoglossal)

Question 9

All sympathetic fibers in the head are what?

Answer 9

Postganglionic arising from the superior cervical ganglion of the sympathetic trunk They travel on vessels to the structures that they innervate (deep petrosal nerve)

Question 10

Preganglionic parasympathetic fibers in the head arise from what?

Answer 10

Nuclei in the brain stem and synapse at 4 ganglia in the head (ciliary, pterygopalatine, otic and submandibular)

Question 11

Which CNs carry preganglionic parasympathetics?

Answer 11

CN III, VII, IX and X

Question 12

All postganglionic fibers in the head piggy back on a branch of what?

Answer 12

The trigeminal to arrive at the structure that they innervate

Question 13

Which CNs are branchiomotor?

Answer 13

V, VII, IX, X and XI

Question 14

What is the function of CN I (olfactory)?

Answer 14

Sensation of olfaction or smell Only type of nervous tissue to regenerate

Question 15

What does damage to olfactory nerve cause?

Answer 15

Anosmia (partial or loss of smell)

Question 16

What is the function of optic nerve (CN II)?

Answer 16

Special sensory: convey visual info from the retina

Question 17

What is caused by damage to the optic nerve?

Answer 17

Anopsia (visual defects)

Question 18

What is the pathway of the olfactory nerve?

Answer 18

Travels through the foramina in the cribiform plate of the ethmoid bone and synapses in the olfactory bulbs located in the anterior cranial fossa

Question 19

What is the pathway of the optic nerve?

Answer 19

Enters cranium via optic foramen of sphenoid bone Left and right optic nerves unit at optic chains Optic tracts travel to lateral geniculate nucleus of thalamus Information is forwarded to the occipital lobe

Question 20

What is the somatic motor/GSE function of the oculomotor nerve (CN III)?

Answer 20

To supply the levator palpebrae superioris, superior rectus, medial rectus, inferior rectus and inferior oblique muscles of the eye Supplies 4 extrinsic eye muscles

Question 21

What is the visceral motor/GVE function of the oculomotor nerve?

Answer 21

Provides the parasympathetic supply to constrictor pupillae and ciliary muscles via the ciliary ganglion Contracts ciliary muscles to make the lens of eye more spherical (as needed for near vision)

Question 22

What is the pathway of the oculomotor nerve?

Answer 22

Leaves cranium via superior orbital fissure and travels to eye and eyelid (parasympathetic fibers travel to ciliary ganglion and postganglionic parasympathetic fibers then travel to iris and ciliary muscle)

Question 23

Which conditions are caused by damage to the oculomotor nerve?

Answer 23

Ptosis (upper eyelid droop), paralysis of eye muscles, leading to strabismus (eyes not in parallel/dedicated improperly), diplopia (double vision) and focusing difficulties

Question 24

What is the function of the trochlear nerve (CN IV)?

Answer 24

To supply the superior oblique muscle of the eye that loops through a pulley shaped ligament to move eyeball inferiorly and laterally (down and out)

Question 25

What is the pathway of the trochlear nerve?

Answer 25

Leaves cranium via superior orbital fissure and travels to superior oblique muscle

Question 26

What conditions are caused by damage to the trochlear nerve?

Answer 26

Paralysis of superior oblique, leading to strabismus (eyes not in parallel/deviated improperly), diplopia (double vision)

Question 27

What is the function of the abducens nerve (CN VI)?

Answer 27

To supply the lateral rectus muscle of the eye which abducts the eye (pulls away laterally)

Question 28

What is the pathway of the abducens nerve?

Answer 28

Leaves cranium through superior orbital fissure and travels to lateral rectus muscle

Question 29

What conditions are caused by damage to the abducens nerve?

Answer 29

Paralysis of the lateral rectus limiting lateral movement of the eye and diplopia (double vision)

Question 30

What is right oculomotor nerve palsy?

Answer 30

Downward and outward gaze of the right eye Dilated pupil, ptosis

Question 31

What is left abducent nerve palsy?

Answer 31

L eye does not abduct (cannot move eye outward/laterally)

Question 32

What is the branchial motor/SVE function of the trigeminal nerve?

Answer 32

Innervate muscles of mastication, tensor tympani, tensor palatini, mylohyoid and anterior belly of digastric

Question 33

What is the general sensory/GSA function of the trigeminal nerve?

Answer 33

From the face and scalp as far as the top of the head, conjunctiva, bulb of the eye, mucous membranes of paranasal sinuses, nasal and oral cavities including tongue and teeth, part of the external aspect of the TM, and fro the meninges of the anterior and middle cranial fossa

Question 34

CN V1 conducts sensory impulses from what structures?

Answer 34

Cornea, nose, forehead and anterior scalp

Question 35

CN V2 conducts sensory impulses from which structures?

Answer 35

Nasal mucosa, palate, gums and cheek

Question 36

CN V3 conducts sensory impulses from which structures?

Answer 36

Anterior 2/3 of tongue, skin of chin, lower jaw, lower teeth, 1/3 from sensory fibers of auricle of ear

Question 37

What are the three branches of the trigeminal nerve (CN V)?

Answer 37

Ophthalmic (VI), maxillary (V2) and mandibular (V3) which receive sensory impulses from face, oral cavity, nasal cavity, anterior scalp

Question 38

What conditions are caused by damage to the trigeminal nerve?

Answer 38

Trigeminal neuralgia (tic douloureux) which is caused by inflammation of the sensory components of the trigeminal nerve and results in intense, pulsating pain lasting from minutes to several hours

Question 39

What are the branches of the ophthalmic branch of CN V?

Answer 39

Lacrimal, frontal (supratrochlear and supraorbital), nasociliary (long and short ciliary, infratrochlear, ethmoidal) and meningeal branch nerves

Question 40

What are the branches of the maxillary branch of CN V?

Answer 40

Zygomatic, Infraorbital, superior alveolar, palatine and meningeal nerves

Question 41

What are the branches of the mandibular branch of CN V?

Answer 41

Buccal, lingual, inferior alveolar and auriculotemporal nerves

Question 42

What are the brachiomotor branches of the mandibular nerve (V3)?

Answer 42

Medial ptergoid, lateral pterygoid, masseteric, deep temporal and mylohyoid nerves