2 - Cranial Nerves 2

Question 1

What is the trigeminal nerve?

Answer 1

CNV

The major sensory nerve to the skin of face and to underlying structures

3 main divisions:
V1 = ophthalmic (sensory)
V2 = maxillary (sensory)
V3 = mandibular (sensory & motor)

Question 2

Ophthalmic branch supplies what?

The major branches are…

Where does the nerve emerge on the face?

Answer 2

Supplies sensory innervation to upper eyelid and upper part of nasal cavity

• frontal > skin of forehead
• lacrimal > lateral skin of upper eyelid & conjunctiva
• nasociliary >medial skin of upper eyelid, conjunctiva & upper part of nasal cavity

Supraorbital foramen - spreads across forehead

Question 3

Maxillary branch supplies what?

What are the branches of the maxillary branch?

Where does the nerve emerge on the face?

Answer 3

Supplies sensory innervation to:

• skin from lower eyelid to upper lip
• maxillary teeth (alveolar nerves)
• palate
• most/lower part of nasal cavity

Branches:
Infraorbital nerve
Zygomatic nerve
Palatine nerve
Nasopalatine nerve
Soñé Opal atine Ganglion

Infraorbital nerve emerges from infraorbital foramen

Question 4

What does the mandibular branch supply?

What are the branches

Where does the nerve emerge

Answer 4

Supplies sensory innervation to
Lower teeth > inferior alveolar nerve
Anterior 2/3 of tongue & floor of mouth > lingual nerve

Supplies motor innervation to muscles of mastication & other muscles

Buccal
Mental
Auriculotemporal

Mental nerve (skin of lower lip and chin) emerges at mental foramen

Question 5

Give a clinical test for the trigeminal nerve

Answer 5

Sharp blunt test over all divisions - can patient distinguish between sharp and blunt

For motor function ask to clench teeth, palpate temporalis and masseter muscles - ask to protrude jaw, if there’s damage it will deviate to injured side

Question 6

What is the facial nerve (number)?

What does it supply?

What are the branches

Answer 6

CNVII

Motor innervation to muscles of facial expression
Special taste sensation to anterior of tongue > chorda tympani
Lacrimal glands, submandibular & Sublingual salivary glands > Parasympathetic and secretomotor nerves

Frontal/temporal 
Zygomatic
Buccal
Marginal mandibular 
Cervical

Question 7

Give a functional tests for the facial nerve

How does Botox affect the facial nerve?

Answer 7

• ask patient to make exaggerated facial expressions
• inspect facial droop or asymmetry
• wrinkle forehead, screw up eyes tightly
• purse lips and puff out cheeks
• stimulate taste on anterior 2/3 of tongue

Botox blocks neurotransmission in facial nerve preventing muscles from creasing the skin

Question 8

What damage occurs when specific areas are affected

Answer 8

Between brainstem and middle ear = all branches and functions are lost
After middle ear = taste and lacrimation in tact but facial expression lost on that side
On face = individual muscle groups lost depending on the branches damaged