Cranial Nerves

Question 1

I

Answer 1

Olfactory (sensory) olfactory

nucleusl location -

origin -

innervation target -

type (motor/sensory/mixed) -

Question 2

II

Answer 2

Optic (sensory) visual

nucleusl location -

origin -

innervation target -

type -

Question 3

III

Answer 3

Oculomotor

nucleusl location - medially in rostral midbrain

origin - receives bilateral innervation from frontal eye field; Exits brain ventrally in interpeduncular fossa

innervation target - all extraocular muscles for eye movement and elevates eyebrow

type - motor (visual)

Question 4

IV

Answer 4

Trochlear

nucleus location - medially in caudal midbrain

origin - (decussates in midbrain) Exits dorsally below inferior colliculus (all others

exit ventrally)

innervation target - superior oblique muscle that rotates eye medially and downward

type - (motor) visual

Question 5

V

Answer 5

Trigeminal

nucleus location - Nuclei is distributed continuously throughout brainstem

origin - But nerve root exits from ventrolateral pons

innervation target - Innervates face, anterior scalp, portion of meninges, oral tract, nasal mucosa, teeth and anterior 2/3 of tongue

type - (mixed) visual

Question 6

VI

Answer 6

Abducens

nucleus location - medially in caudal pons

origin - Exits brain ventrally at pontomedullary junction

innervation target - Innervates lateral rectus muscle; Controls eye abduction

type - (motor) visual

Question 7

VII

Answer 7

Facial

nucleusl location - motor nucleus in caudal pons

origin - Exits pontomedullary junction laterally relative to CN VI (cerebellopontine angle)

innervation target - Nerve divides into 5 branches to innervate muscles: Temporal, zygomatic, buccal, mandibular and cervical

type - (mixed) motor speech and swallowing

Question 8

VIII

Answer 8

Vestibulocochlear/Auditory/Acoustic

nucleusl location - Nuclei located ventrolaterally in pontomedullary junction

origin - Enter brainstem laterally to CN VII in cerebellopontine angle

innervation target -

type - (sensory) Auditory and balance

Question 9

IX

Answer 9

Glossopharyngeal

nucleus location -

origin - Visceral motor fibers originate in the inferior salivatory nucleus and innervate the parotid gland

innervation target - General somatic efferent fibers innervate the stylopharyngeus (active during swallow and is part of the efferent arm of the gag reflex )

type - (mixed) Motor speech and swallowing

Question 10

X

Answer 10

Vagus

nucleusl location -

origin - Exits post‐olivary sulcus lateral to hypoglossal as multiple rootlets

innervation target - (motor) muscles of pharynx and larynx; (sensory) Lower pharynx, larynx, trachea, posterior meninges, portion of external ear canal

type - (mixed) motor speech and swallowing

Question 11

XI

Answer 11

(Spinal) Accessory

nucleusl location - Nucleus is in spinal cord but fibers move rostrally and exit brainstem

origin -

innervation target - the sternomastoid and upper fibers of the trapezius

type - (motor) motor speech and swallowing

Question 12

XII

Answer 12

Hypoglossal (motor) motor speech swallowing

nucleusl location -

origin - Nerve exits ventral medulla as multiple rootlets between pyramid and inferior olive

innervation target - somatic motor innervation to all muscles of tongue (intrinsic and extrinsic); multiple muscles that connect to the hyoid bone

type -