The three branches of the trigeminal nerve are the ophthalmic, maxillary, and mandibular nerves. The maxillary nerve has branches that innervate the maxillary teeth and gingiva. The mandibular nerve has both sensory and motor branches, with the posterior division providing sensory innervation to the mandibular teeth, gingiva and other structures. The trigeminal nerve is the most important nerve for dentistry as it provides sensory innervation to the face, teeth and oral cavity.

1. Nerves of the Head
and Neck
CHAPTER 19

2. General Information
Nervous system has two parts
Central nervous system (CNS)
Peripheral nervous system (PNS)
CNS is further classified into two parts
Brain, which is housed in cranium
Spinal cord, which is contained within vertebral
column

3. General Information
PNS is comprised of nerves that travel away from the
CNS
12 pairs of cranial nerves
31 pairs of spinal nerves
All parts of the body are connected to the CNS through
the PNS
A nerve cell is also known as a neuron, which has
three parts.

4. Shapes of Neurons
 Three parts of neurons include:
The Cell Body
Dendrite
A process that conducts impulses toward
the cell body.
A neuron may have one or many
dendrites
Axon
A process that carries impulses away
from the cell body.
A neuron only has one axon.

5. Nerves
 Sensory or Afferent: Carry impulses or messages toward the brain
 Motor or Efferent: carry impulses away from the brain
 Somatic nerves: Supply muscles
 Visceral nerves: supply internal organs (viscera)
 Autonomic Nervous System (ANS): regulates those functions over
which we have NO CONSCIOUS CONTROL
 Heart rate and respiratory
 ANS is divided into two groups:
 Sympathetic and parasympathetic

6. The Sympathetic System
Functions in response to emergencies
Sympathetic nerves increase respiration, heart rate,
and blood flow to muscles.
They decrease salivary flow and blood supply to the
digestive tract so that additional blood can be
supplied to the other muscles
Fight or Flight reaction

7. Fight or Flight
 If someone frightens you, the sympathetic nervous system is activated, and the
following things happen:
 Heart beats fast and strong because of the release of adrenalin
 You become pale
 Your skin feels clammy from shut down of surface capillaries
 You feel a knot in your stomach from the shut down of the blood supply to the digestive tract.
 all of this blood is shunted to the skeletal muscles of your body
 Your heart beats faster, and your breathing faster so that you are getting more oxygen into th
ebody, which then goes to the muscles.
 The adrenalain helps with actions of the heart and lungs and enables the body to meet stressful
situations.
 You may also find that your mouth is very dry from the shutdown of salivary glands, and the
pupil of your eye dilates to let in more light, so you can see better.

8. The Parasympathetic System
 Stimulation of the parasympathetic system does the opposite
of the sympathetic. They are antagonists.
 Referred to as the “vegetative System”, "rest-and-digest" or
"feed and breed“
occurs when the body is at rest, especially after eating, salivation,
lacrimation (tears), urination, digestion and defecation.
Slows down the heart and respiration, increases blood flow to the
digestive system, increases peristaltic contractions, and stimulates
secretions of the glands of the body, including the salivary glands

9. Cranial Nerves
12 sets of paired cranial nerves
Innervate right/left sides of body, designated by
Roman numerals
May be sensory, motor, or combination (mixed)
Four cranial nerves important for dentistry
Trigeminal (V), facial (VII),
glossopharyngeal (IX), and hypoglossal (XII)

10. Trigeminal Nerve (V) (Mixed)
 Largest cranial nerve
Most important nerve to the dental assistant
Provides innervation from face, scalp, teeth, nose, and mouth
Also distributes motor innervation to the muscles of mastication and
provides parasympathetic supply to the salivary and lacrimal glands.
Sensory cells are located in the semilunar (gasserian) ganglion found
in the petrous portion of the temporal bone.
The motor root originates in the pons and joins the mandibular
division

11. Trigeminal Nerve (V)

12. Trigeminal Nerve (V)

13. Petrous Part (pink portion)
 The petrous part of the temporal bone
is pyramid-shaped and is wedged in at
the base of the skull between the
sphenoid and occipital bones.
 Directed medially, forward, and a little
upward, it presents a base, an apex,
three surfaces, and three angles, and
houses in its interior, the components
of the inner ear.

14. Trigeminal Nerve (V)
Three divisions or branches
Ophthalmic nerve (V1): entirely afferent
Maxillary nerve (V2): entirely afferent
Mandibular nerve (V3): mixed

15. Ophthalmic Nerve (V1)
Enters eye through superior
orbital fissure
Provides sensory innervation
to eye, nose, lacrimal gland,
and skin of eyelids, forehead,
and nose

16. Ophthalmic Nerve (V1)
 Three branches (none lead to oral cavity)
 Lacrimal nerve innervates the lacrimal glands for tear production and supply
the skin of the upper eyelid
 Frontal nerve passes above the eye, dividing into supraorbital and supraochlear
nerves.
Supraorbital supplies skin of the forehead, scalp, and upper eyelid
Supraochlear supplies the skin of the forehead and upper eyelid
 Nasociliary nerve runs within the orbit, passes through the ethmoid bone, and
re-enters the cranium at the cribriform plate of the ethmoid bone. It then
passes down into the nose and supplies the inside of the nose.
Its branch, the infratrochlear nerve, supplies the medial side of the eyelids and side
of the nose.

17. What are the three branches of the
Ophthalmic Nerve?
Lacrimal, Frontal,
Nasociliary

18. Ophthalmic Nerve (V1)

19. Maxillary Nerve (V2)
Second division of the trigeminal
nerve
Exits through foramen rotundum and
passes into pterygopalatine fossa
In this fossa, the maxillary nerve
divides into four branches.
Zygomatic, infraorbital, posterior
superior alveolar (PSA), and
pterygopalatine

20. Maxillary Nerve (V2)

21. Maxillary Nerve (V2) Branches
Zygomatic (1)
Enters eye through inferior
orbital fissure and has two
branches
Zygomaticotemporal: supplies
skin and side of forehead
Zygomaticofacial: supplies skin of
cheek

22. Maxillary Nerve (V2) Branches
 Infraorbital nerve (2)
 Emerges onto the face through the infraorbital foramen giving off two
descending branches
Middle superior alveolar nerve provides innervation to mesiobuccal roots of
maxillary first molars, maxillary first and second premolars, and the adjacent
gingiva, and the maxillary sinus.
The MSA is not always present. If it is not present, innervation to the area is
provided by the ASA and PSA
Anterior superior alveolar supplies the maxillary incisor, canine teeth and
associated labial gingiva.
It also innervates the maxillary sinus

23. Infraorbital Nerve (V2) (branch of Maxillary)
 After the infraorbital nerve emerges
onto the face through the infraorbital
foramen, it divides into the following
three TERMINAL branches.
Palpebral- Supplies the skin of the lower
eyelid
External nasal- innervates the skin and
mucosa of the side of the nose
Superior labial- supplies the skin and
mucosa of the upper lip and labial
mucosa

24. Maxillary Nerve (V2)

25. Maxillary Nerve (V2) branches
 Before the infraorbital nerve enters the infraorbital groove, it gives
off the Posterior Superior Alveolar Nerve (3)
 It crosses the maxillary tuberosity and supplies the maxillary
molars, with the exception of the Mesiobuccal root of the maxillary
first molar (which is innervated by the MSA, remember?)
 Also supplies the adjacent buccal gingiva and maxillary sinus

26. Maxillary Nerve (V2) Pterygopalatine
Nerves
 Five branches of maxillary nerve given off in pterygopalatine fossa
 Pharyngeal supplies pharynx and pharyngeal mucosa
 Greater palatine enters the greater palatin foramen (palatine bone) to supply mucosa to the
hard palate and lingual gingiva of maxillary molars, premolars and canines
 Lesser palatine enters the lesser palatine foramen to supply mucosa to soft palate and tonsils
 Nasopalatine passes through the Nasopalatine (incisive) foramen of the maxilla to supply the
lingual gingiva of maxillary incisors
 Posterior superior lateral nasal supplies middle and superior nasal conchae and superior nasal
septum

27. Maxillary Nerve (V2)

28. Mandibular Nerve (V3)
Largest division of trigeminal nerve
Sensory branch gives off the meningeal nerve
Exits the skull through the foramen ovale in the sphenoid
bone
Its both afferent and efferent
After the foramen ovale, the sensory and motor roots unite
in a short trunk.
The sensory branch gives off the meningeal nerve
Passes through foramen spinosum to supply meninges

29. Mandibular Nerve (V3)
Motor branch distributes nerves to the following
muscles:
medial pterygoid
tensor tympani
tensor veli palatini
The mandibular nerve then branches into the
anterior and posterior divisions

30. Mandibular Nerve (V3)
Anterior division
Only one sensory branch
Buccal (long buccal) nerve
It crosses between the two heads of th elateral pterygoid
muscle and emerges through the buccinator muscle.
It innervates the buccal gingiva of the mandibular molars and
premolars, the mucosa of the cheek and the skin of the cheek.
NO TEETH/BONE!!!!

31. Mandibular Nerve (V3)
Anterior Division
The remaining nerves are all motor to the muscles
of mastication.
Motor
Masseteric – supplies masseter muscle
Anterior/posterior deep temporal nerves – supplies
temporalis muscle
Lateral pterygoid – supplies lateral pterygoid muscle

32. Mandibular Nerve (V3)

33. Mandibular Nerve (V3)
Posterior Division
This division only has one motor branch; the remaining
branches are all sensory.
Auriculotemporal nerve supplies the temporal region in
front of the ear, the external acoustic (auditory)
meatus, and the temporomandibular joint.
After giving off the Auriculotemporal nerve, the mandibular
nerve divides into two TERMINAL branches.

34. Mandibular Nerve (V3)
Posterior Division
Lingual nerve runs between medial pterygoid muscle
and mandible, joined by chorda tympani, a branch of
facial nerve (VII)
Together, the lingual and chorda tympani nerves enter the
posterior aspect of the mouth and run forward.
The chorda tympani supplies taste sensation to the anterior
two thirds of the tongue.

35. Mandibular Nerve (V3)
Posterior Division
The lingual nerve enters the floor of the mouth and
ventral surface of the tongue.
It supplies afferent innervation to the tongue, floor of
the mouth, and lingual gingiva of the entire mandibular
arch.
NOT BONE OR TEETH!!

36. Mandibular Nerve (V3)
Posterior Division
 Inferior alveolar nerve
Runs parallel with the lingual nerve and enters the mandible
through the mandibular foramen and continues through the
mandibular canal
Before it enters the mandibular foramen, it gives off the Mylohyoid
nerve, the only motor branch in the posterior division.
It supplies efferent sensation to the Mylohyoid muscle and the
anterior belly of the digastric muscle.
After giving off the Mylohyoid nerve, the IA is entirely sensory.

37. Mandibular Nerve (V3)
Posterior Division
 Within the mandibular canal, the IA gives off branches to the
mandibular molars and premolars.
 At the mental foramen, it divides into the following nerves:
 Mental: supplies the chin and lower lip
 Incisive: supplies the mandibular anterior TEETH and labial gingiva

38. What are the three branches of the
Trigeminal Nerve?
Ophthalmic, Maxillary,
Mandibular