Exam 2 - Cranial Nerves

Question 1

Sensory Cranial Nerves

Answer 1

CN I, II, VIII

Question 2

Motor Cranial Nerves

Answer 2

CN III, IV, VI, XI, XII

Question 3

Mixed Cranial Nerves

Answer 3

CN V, VII, IX, X

Question 4

CN III
Function
Course

Answer 4

Oculomotor nerve
Innervates 5 extraoccular muscles - 4 of the extrinsic eye muscles
Course: exits midbrain between the cerebral peduncles, exits cranium superior orbital fissure

Question 5

CN III

GSE Component

Answer 5

1) Levator palbebrae superioris - controls upper eyelids
2) Superior rectus
3) Inferior oblique
4) Inferior rectus
5) Medial rectus

Question 6

Lesion to CN III

Answer 6

Palpebrae ptosis - damage to innervation of levator palbebrae superioris (eyelid droops)
External strabismus - damage to medial rectus (eye looks outward)

Question 7

CN IV

Answer 7

innervates superior oblique muscle

Lesion results in eye rotating laterally to compensate and correct for diplopia, head turns to opposite side

Question 8

CN V

Answer 8

Trigeminal nerve
Sensory innervation to face, motor innervation to chewing muscles
Originates from pons
Carries GSE fibers from the face

Question 9

V(1)

&clinical

Answer 9

Superior orbital fissure
Opthalmic branch
Inflammation = Herpes Zoster

Question 10

V2

Answer 10

Foramen rotundum
Maxillary branch
Upper teeth

Question 11

V3

Answer 11

Foramen ovale
Manibular branch
Lower teeth, general sensations of tongue (anterior 2/3 of tongue)

Question 12

SVE fibers in V3 innervate skeletal muscles derived from the 1st branchial arch

Answer 12

1) muscles of mastication
2) Ant belly of diagastric
3) Tensor tympani
4) Tensor veli palatini

Question 13

CN VI

&clinical

Answer 13

Abducens nerve
Abducts the eyeball (lateral rectus)
Damage = cross-eyed (Abducens palsy, internal strabismus)

Question 14

CN VII

Answer 14

Facial nerve
sensory innervation of face
innervates muscles of facial expression
taste (anterior 2/3 of tongue)
Exits posterior cranial fossa through internal auditory meatus, exits stylomastoid foramen

Question 15

Facial canal

Answer 15

in petrous portion of temporal bone
connects internal auditory meatus and stylomastoid foramen
potential site for compression injuries if CNVII becomes inflamed (ie herpes infection)

Question 16

Motor branches of CN VII

Answer 16

1) temporal (occipitofrontalis)
2) zygomatic
3) buccal
4) mandibular
5) cervical
6) auricular

Question 17

CN VII SVE

Answer 17

muscles of facial expression

stapedius, buccinator, posterior belly of digastic, stylohyoid

Question 18

Bell’s Palsy

Answer 18

Lack of wrinkles on affected side
Mouth drawn to unaffected side
Hyperacusia

Question 19

Chorda tympani

Answer 19

1) crosses tympanic membrane
2) exits ptero-tympanic fissure
3) joins linguinal nerve in infratemporal fossa
4) terminates in submandibular ganglion
5) tastes to anter 2/3 of tongue
6) secretomotor to sublingual and submandibular glands