Cranial Nerves

Question 1

Pathway of CN I nerve:

Answer 1

Olfactory nerve:

pass through foraminifera in cribriform plate of ethmoid bone and enter olfactory bulb in the anterior cranial fossa.

Question 2

Components of CN I

Answer 2

Special sensory - smell

Question 3

Pathway of CN II

Answer 3

Optic nerve:
enters via optic canal, nerves join to form optic chasm, fibres from medial half of each retina cross to form optic tract.

Question 4

Components of CN II

Answer 4

Special sensory - vision

Question 5

Pathway of CN III

Answer 5

Oculomotor:

Emerges from midbrain and exits via superior orbital fissure

Question 6

Components of CN III

Answer 6

Somatic motor - extra ocular muscles and eyelid
visceral motor - parasympathetic to pupil causing constriction and to ciliary muscle causing accommodation of the lens.
MOVEMENTS OF EYES

Question 7

Components of CN IV

Answer 7

Trochlear:

somatic motor - extra ocular muscle

Question 8

Pathway of CN V1

Answer 8

Trigeminal (opthalmic)

emerges from pons, travels through the trigeminal ganglion and exits via superior orbital fissure

Question 9

Components of CN V1

Answer 9

general sensory - from forehead,scalp,nose,eyelids and mucosa of nasal cavity and sinuses.

Question 10

Pathway of CN V2

Answer 10

Trigeminal (maxillary):

exits via the foramen rotundum

Question 11

Components of CN V2

Answer 11

General sensory - from face over maxilla, maxillary teeth, temperomandibular joint, mucosa of nose, maxillary sinuses and palate

Question 12

Pathway CN V3

Answer 12

Trigeminal (mandibular):
exits via the foramen oval
Chewing

Question 13

Pathway of CN VI

Answer 13

emerges between pons and medulla and exits via the superior orbital fissure

Question 14

Components of CN VI

Answer 14

somatic motor - extra ocular muscle

Question 15

Pathway of CN VII

Answer 15

Facial Nerve:

emerges between pons and medulla and exits via internal acoustic meatus, facial canal and stylomastoid foramen

Question 16

Components of CN VII

Answer 16

somatic motor - muscles of facial expression
visceral motor - parasympathetic innervation of submandibular and sublingual salivary glands
special sensory - taste from anterior 2/3rd of tongue

Question 17

Pathway of CN VIII

Answer 17

Vestibulocochlear:

emerges between pons and medulla and exits via internal acoustic meatus, dividing into vestibular and cochlear nerves

Question 18

Components of CN VIII

Answer 18

Special sensory - vestibular sensation from semicircular ducts, utricle. Hearing.

Question 19

Pathway of CN X

Answer 19

Vagus:

emerges from medulla and exits via jugular foramen, then everywhere

Question 20

Components of CN X

Answer 20

special sensory - taste
general sensory - sensation from auricle
visceral sensory - from pharynx, larynx, trachea…
visceral motor - parasympathetic innervation muscle in bronchi, gut, heart
somatic motor - pharynx, larynx

Question 21

Pathway of CN IX

Answer 21

Glossopharyngeal:

emerges from medulla and exits via jugular foramen

Question 22

Components of CN IX

Answer 22

special sensory - taste from posterior 3rd of tongue
general sensory - cutaneous sensations from middle ear
visceral sensory - sensation from carotid body & carotid sinus
visceral motor - parasympathetic innervation of parotid gland
somatic motor - to stylopharyngeus, helps with swallowing

Question 23

Pathway of CN XI

Answer 23

Accessory:
small cranial (medulla) and large spinal roots exit via jugular foramen.

Question 24

Components of CN XI

Answer 24

Somatic motor - striated muscle of soft palate, pharynx and larynx, and to sternocleidomastoid and trapezius

Question 25

Pathway CN XII

Answer 25

Hypoglossal:

emerges from medulla and exits through the hypoglossal canal

Question 26

Components CN XII

Answer 26

somatic motor - to muscles of tongue

Question 27

Pathway of CN IV

Answer 27

emerges from dorsal surface of the mid brain and exits via the superior orbital fissure