Trigeminal Nerve

Question 1

Name the 3 major divisions of the trigeminal nerve

Answer 1

opthalmic, maxillary and mandibular

Question 2

Name function of opthalmic nerve and where does it exit?

Answer 2

somatic sensory, exits superorbital fissue

Question 3

Name nerves that branch off the opthalmic nerve

Answer 3

Tentorial n
Nasociliary N
Frontal N
Lacramal N

Question 4

What does the tentorial n innervate and where is it located?

Answer 4

in the middle cranial fossa, serves dura mater of tentorial cerebelli

Question 5

How does the Nasociliary N branch? Where does it originate in?

Answer 5

sensory fibers to cilliary ganglion
Long cilliary root
Posterior ethmoid
Anterior ethmoid
Infratrochlear n

Question 6

Sensory root of the cilliary ganglion route and function:

Answer 6

V1 -> nasocilliary -> sensory root ganglion - sensory fibers that pass through the cilliary ganglion to subserve structures within the eye.

Question 7

Long cilliary root route and function:

Answer 7

• alt route for sensory fibers to eyeball

Question 8

posterior ethmoid nerve route and function:

Answer 8

• from Nasociliary n -> transits small foramina on the media surface of the orbit (through frontal bone near its junction with the orbital plate of the ethmoid bone
• Subserves the ethmoidal aircells and sphenoid sinus

Question 9

anterior ethmoidal nerve route and function

Answer 9

• from Nasociliary n -> transits small foramina on the media surface of the orbit (through frontal bone near its junction with the orbital plate of the ethmoid bone
• Subserves the ethmoidal aircells and sphenoid sinus
• Small branches transit through the ethmoid bone and subserve skinover the superior rim of nose (external branches of the anterior ethmoid nerve) and some subserve the dura mater (anterior meningeal branch of the anterior ethmoid nerve)

Question 10

Descirbe the Frontal nerve

Answer 10

splits into supraorbital n and supratrochlear nerve from v1 after it passes through the superior orbital fissure

Question 11

Supraorbital n

Answer 11

from v1 -> frontal n. originates in orbit. larger than supratrochlear n, subserves skin of the forehead; more lateral than supratrochlear

Question 12

Supratrochlear n.

Answer 12

from v1-> frontal n. smaller than frontal n. near medial edge of orbital rim. subserves medial portions of the skin of the forehead. more medial than supraorbital n

Question 13

Lacrimal n

Answer 13

originates in orbital fissure from v1. subserves lacrimal gland (sensory). located on lateral edge of orbital rim. subserves small patch of skin superior and lateral to the eye

Question 14

Describe the maxillary nerve and route.

Answer 14

Entirely somatic sensory in function; exits the middle cranial fossa via the foramen rotundum.

Question 15

What are the branches of the maxillary nerve?

Answer 15

A. Meningeal branch of the Maxillary Nerve

B. Zygomatic nerve – originates within the orbit

C. Ganglionic branches to the pterygopalatine ganglion

D. Posterior superior alveolar nerve

E. Middle superior alveolar nerve

F. Anterior superior alveolar nerve

G. Infraorbital nerve

Question 16

Meningeal branch of the Maxillary Nerve originates from and does what?

Answer 16

• Originates within the middle cranial fossa

* Subserves the dura mater of medial portions of the anterior and middle cranial fossae.

Question 17

Zygomatic nerve originates from where and does what?

Answer 17

– originates within the orbit
Gives off two branches:
1. Zygomaticotemporal nerve
2. Zygomaticofacial nerve

Question 18

Zygomaticotemporal nerve route and function?

Answer 18

• Forms the “cummuncating branch of the zygomaticotemporal nerve” that carries hitchhiking post-ganglionic parasympathetic fibers to the
lacrimal nerve (which then innervate the glandular cells of the lacrimal gland)
• Transits the zygomaticotemporal foramen of the zygomatic bone to subserve the skin overlying the superior zygoma

Question 19

Zygomaticofacial nerve route and function?

Answer 19

transits the zygomaticofacial foramen of the

zygomatic bone to subserve the skin overlying the inferior zygoma

Question 20

Ganglionic branches to the pterygopalatine ganglion has what type of fibers and what branches off of it?

Answer 20

– contains sensory fibers that pass through the pterygopalatine ganglion to enter one of the
following nerves.
1. Greater palatine nerve

2. Lesser palatine nerve
3. Nasopalatine nerve
4. Posterior superior lateral nasal branch of the maxillary nerve

Question 21

Greater palatine nerve originates in and does what?

Answer 21

• Originates within the sphenopalatine fossa
• Gives rise to posterior inferior lateral nasal branch of the greater palatine nerve that subserves the inferior-lateral portions of the nasal cavities (i.e., the inferior nasal cocha)
• Transits through the greater palatine foramen (at the junction of the horizontal plate of the palatine bone and the maxillary bone) to enter the
oral cavity
• Subserves the oral mucosa of the hard palate on the roof of the mouth
• Communicates with the nasopalatine nerve through the incisive foramen of the maxillary bone

Question 22

2. Lesser palatine nerve originates in and does what?

Answer 22

• Originates within the sphenopalatine fossa
• Transits through the lesser palatine foramen on the horizontal plate of the palatine bone
• Subserves the oral mucosa of the soft palate on the roof of the mouth

Question 23

Nasopalatine nerve originates in and does what?

Answer 23

• Originates from the pterygopalatine ganglion (or greater palatine nerve)
• Subserves the nasal mucosa of the nasal septum
• Communicates with the greater palatine neve through the incisive foramen of the maxillary bone

Question 24

Posterior superior alveolar nerve originates in and does what?

Answer 24

• Originates within the sphenopalatine fossa
• Transits through the posterior superior alveolar foramen of the maxillary bone
• Subserves the nasal mucosa of the maxillary sinus and the upper teeth
• Communicates with the middle and anterior superior alveolar nerves within the maxillary bone

Question 25

Middle superior alveolar nerve originates in and does what?

Answer 25

* Originates within the orbit * Transits through the middle superior alveolar foramen of the maxillary bone * Subserves the nasal mucosa of the maxillary sinus and the upper teeth * Communicates with the posterior and anterior superior alveolar nerves

Question 26

Anterior superior alveolar nerve originates in and does what?

Answer 26

* Originates within the infraorbital foramen * Transits through the anterior superior alveolar foramen of the maxillary bone * Subserves the nasal mucosa of the maxillary sinus and the upper teeth * Communicates with the middle and posterior superior alveolar nerves

Question 27

Infraorbital nerve originates in and does what?

Answer 27

-- transits through the infraorbital foramen to subserve the skin on the lateral portions of the nose and anterior portions of the face from the lower eyelid inferior to the upper lip

Question 28

Mandibular Nerve has what kind of fibers, and what is its route?

Answer 28

-- Contains BOTH somatic (general) sensory and branchial motor fibers; Route: exits the middle cranial fossa via the foramen ovale

Question 29

What are the branches of the Mandibular nerve?

Answer 29

A. Meningeal branch of the mandibular nerve B. Auriculotemporal nerve C. Buccal nerve D. Lingual nerve E. Muscular branches of the mandibular nerve F. Inferior alveolar nerve (and Mental Nerve)

Question 30

Meningeal branch of the mandibular nerve originates in and does what?

Answer 30

• Originates just inferior to the foramen ovale • Re-enters the middle cranial fossa via the foramen Spinosum (a.k.a. nervus spinosum) • Entirely sensory; subserves the dura mater of lateral portions of the middle cranialfossa

Question 31

Auriculotemporal nerve originates in and does what?

Answer 31

• Originates just inferior to the foramen ovale • Subserves lateral portions of the head, just anterior to the external auditory meatus

Question 32

Buccal nerve originates in and does what?

Answer 32

* Originates inferior to the foramen ovale * Contains only somatic sensory fibers * Subserves BOTH the inner and outer walls of the cheek

Question 33

Lingual nerve originates in and does what?

Answer 33

* Originates inferior to the foramen ovale * Contains only somatic sensory fibers * Subserves the floor of the oral cavity

Question 34

Muscular branches of the mandibular nerve originates in and does what?

Answer 34

• Originate just inferior to the foramen ovale • Contain both branchial motor fibers innervating the named nerve, as well as somatic sensory fibers carrying proprioceptive feedback from those muscle to the CNS. 1. Nerve to the masseter muscle 2. Deep temporal nerves (subserve the temporalis muscle) 3. Nerve to the medial pterygoid muscle 4. Nerve to the lateral pterygoid muscle 5. Nerve to the tensor veli palatini muscle 6. Nerve to the tensor tympani muscle

Question 35

Inferior alveolar nerve (and Mental Nerve) originates in and does what?

Answer 35

• Originates inferior to the foramen ovale • Contains both branchial motor fibers and somatic sensory fibers • Splits to form the mylohyoid nerve just superior to the mandibular foramen – the portion that enters the mandibular foramen is still called the inferior alveolar nerve that will transit through the mental foramen to become the mental nerve

Question 36

Mylohyoid nerve originates in and does what?

Answer 36

--contains both branchial motor fibers innervating the named nerve, as well as somatic sensory fibers carrying proprioceptive feedback from those muscles to the CNS. a. Nerve to the mylohyoid muscle b. Nerve to the anterior belly of the digastric muscle

Question 37

Inferior Alveolar Nerve (continuation in the mandibular foramen) originates in and does what?

Answer 37

* Contains only somatic sensory fibers * subserves the roots of the inferior teeth * transits through the mental foramen at the anterior end of the mandibular canal to become the mental nerve; subserves the skin on the chin and superior to the lower lip.

Question 38

Summarize the dermatomal innervations of each branch of the trigeminal nerve.

Answer 38

V1 - Frontonasal prominence V2 - Maxillary prominence plus the lateral and medial olfactory prominences V3 - Mandibular prominence

Question 39

Summarize the muscles innervated by the mandibular N.

Answer 39

2+2+4 = 8 2 tensors • tensor tympani • tensor veli palatini (soft palate) 2 muscles associated with mylohyoid nerve • mylohyoid muscle • anterior belly of the digastric muscle ``` 4 M&M’s= muscles of mastication • masseter muscle • temporalis muscle • medial pterygoid muscle • lateral pterygoid muscle ```