Cranial Nerves

Question 1

How many cranial nerves originate in the brainstem?

Answer 1

10

Question 2

Cranial nerves associated with the parasympathetic division:

Answer 2

-4 cranial nerves
-Oculomotor Nerve (CN III)
-Facial (CN VII)
-Glossopharyngeal (CN IX)
-Vagus nerve

Question 3

CN I: Name, Functional modality and skull passageway

Answer 3

-Name: Olfactory Nerves

Functional Modality
—> Special sensory: olfaction (smell)
Skull Passageway:

—> cribriform plate foramina
Synapses in the olfactory bulbs

Question 4

CN II: Name, Functional modality and skull passageway

Answer 4

Name: Optic nerve
—> Brain tract, covered by meninges

Functional Modality
—> Special sensory: visual sensory information

Skull Passageway
—-> optic canal

Question 5

CN III: Name, Functional modality and skull passageway

Answer 5

Name: Oculomotor nerve

Functional modality
–> Somatic motor: Four of six extrinsic eye
—-> muscles
—-> Superior rectus
—-> Inferior rectus
—-> Medial rectus
—-> Inferior oblique
—-> Also levator palpebrae superioris

—> Visceral motor: Sphincter pupillae, ciliary muscle

Skull passageway
–> superior orbital fissure
—> Pre-ganglionic parasympathetic fibers travel to the ciliary ganglion
—> postganglionic parasympathetic fivers travel to the iris and ciliary muscle

Question 6

CN IV (4): Name, Functional modality and skull passageway

Answer 6

Name
—> Trochlear Nerve

Functional modality
—-> Somatic motor: superior oblique

Skull Passageway
—> superior orbital fissure

Question 7

CN V (5): Name, Functional modality and skull passageway

Answer 7

Name: Trigeminal Nerve

Three divisions:
-Ophthalmic (V1)
—> Skull Passageway: Superior orbital fissure
-Maxillary (V2)
-Mandibular (V3)

Functional modality:
—>Somatic (Special) Motor (V3):
——> Muscles of mastication Mylohyoid
——> Anterior belly of the digastric
——> Tensor tympani muscle
——> Tensor veli palatini
***Mandibular division only!

—> Somatic sensory: touch, temperature, and pain from the face
——> Ophthalmic (V1): cornea, nose, forehead, anterior scalp
——> Maxillary (V2): nasal mucosa,
palate, gums, cheek
——> Mandibular (V3): anterior 2/3 tongue, meninges, skin of the chin, lower jaw, lower teeth, part of the ear

Sensory axons enter the cranium and synapse at the trigeminal ganglion before entering the pons
—> Like the dorsal root ganglion
for the trigeminal nerve

Question 8

CN VI (6): Name, Functional modality and skull passageway

Answer 8

Name: Abducens Nerve

Functional modality
—> Somatic motor: lateral rectus

Skull passageway
—> superior orbital fissure

Question 9

CN VII (7): Name, Functional modality and skull passageway

Answer 9

Name: Facial Nerve

Functional modality:
–> Special sensory: taste from the anterior 2/3 of the tongue

–> Visceral motor: lacrimal, sublingual, & submandibular glands

–> Visceral sensory: Sensory from the above glands

–> Somatic sensory: Small area behind the ear

–> Somatic (Special) motor
——> Posterior belly of the digastric Stylohyoid
——> Stapedius muscles
——> Muscles of facial expression

Preganglionic parasympathetic fibers travel to the pterygopalatine and submandibular glands

Skull passageway
–> enters skull through the internal acoustic meatus
–> branch to the facial muscles exits skull via the
stylomastoid foramen

Question 10

CN VIII (8): Name, Functional modality and skull passageway

Answer 10

Name: Vestibulocochlear Nerve

Functional modality
–> Special Sensory
–> Vestibular branch: equilibrium and balance
–> Cochlear branch: hearing

Skull passageway
–> Internal acoustic meatus

Question 11

CN IX (9): Name, Functional modality and skull passageway

Answer 11

Name: Glossopharyngeal Nerve

Functional modality
–> Special sensory: taste from the posterior
1/3 of the tongue
–> Somatic sensory: pharynx
–> Visceral sensory: carotid bodies,
parotid gland
–> Somatic (Special) motor: stylopharyngeus
–> Visceral motor: parotid gland

Skull passageway
–> Jugular foramen

Preganglionic parasympathetic fibers travel to the otic ganglion

Question 12

CN X (10): Name, Functional modality and skull passageway

Answer 12

Name: Vagus Nerve

Functional modality
–> Special sensory: taste from the base of
the tongue, epiglottis, upper pharynx

–> Visceral motor: heart, pharynx, larynx, trachea, lungs, abdominal organs up to 1st 2/3 transverse colon

–> Visceral sensory: heart, lungs, abdominal organs up to the first 2/3 of the transverse colon

–> Somatic sensory: external acoustic meatus,
eardrum, laryngopharynx, larynx

–>Somatic (Special) motor: pharynx, larynx
and palate muscles
—–> Recurrent laryngeal nerve: branches in
the thorax, left loops under the arch of the aorta,
returns to neck to innervate laryngeal muscles

Skull passageway
—> Jugular foramen

Question 13

CN XI (11): Name, Functional modality and skull passageway

Answer 13

Name: Accessory Nerve

Functional modality
—> Somatic (Special) motor: trapezius and
sternocleidomastoid muscles

Skull passageway
—> Jugular foramen

Name: Hypoglossal Nerve

Functional modalities
—> Somatic motor: intrinsic and
extrinsic muscles of the tongue

Skull passageway:
—> hypoglossal canal