trigeminal nerve v1 & v2 slides

7/27/2019 Trigeminal Nerve V1 & V2 Slides

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Trigeminal Nerve:

V1 and V2

Trigeminal Nerve:

V1 and V2

Alex Forrest

Associate Professor of Forensic OdontologyForensic Science Research & Innovation Centre, Griffith University

Consultant Forensic Odontologist,

Queensland Health Forensic and Scientific Services,

39 Kessels Rd, Coopers Plains, Queensland, Australia 4108

Oral Biology


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Do not remove this notice.


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Learning ObjectivesLearning Objectives

1. You should be able to understand and explain the gross

anatomy of V in detail2. You should be able to understand and explain the anatomy

of V in both structural and functional terms, showing how

these are correlated.


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Learning ObjectivesLearning Objectives

3. You should be able to understand and explain in detail the

nerve supply of the upper and lower teeth, and the

anatomical relations of the nerves involved.

4. You should understand, and be able to explain, how this

information is important in local anaesthesia in the clinical

setting, with particular reference to accessory nervesupplies to oral structures.


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Trigeminal NerveTrigeminal Nerve

The trigeminal nerve, or cranial nerve number five (V), is thecranial nerve of greatest importance to the dentist.


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It is the sensory nerve of

the front of the head andthe face.

It is also the motor nerve

that supplies motorinnervation to the

muscles of mastication,

the anterior belly of the

digastric and the

mylohyoid.

Grays Anatomy, Longmans, London, 38th Ed 1989 p. 1106


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It provides sensory innervation to the oral cavity and to the

dental and paradental structures.

For this reason, it is branches of this nerve that are most

commonly anaesthetized so that otherwise painful dental

procedures can be performed comfortably for patients.


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The three peripheral

divisions of the

trigeminal nerve

supply common

sensation (touch,pressure, temperature

and pain) to the skin of

the front of the face

and the scalp as farback as the vertex of

the head.

Cutaneous DistributionCutaneous Distribution


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The ophthalmic

division (V1) supplies

the skin of the

anterior portion ofthe scalp and the

forehead, the upper

eyelid, and the front

of the nose as fardown as its tip.


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The maxillary


the skin at the side

of the nose, the

lower eyelid and the

upper part of the

cheek and upper lip.


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The mandibular


the chin and lower

lip, the skin in frontof the ear, and the

skin of the side of

the head up to the

area supplied by theophthalmic division.


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The angle of themandible is not

supplied by the

trigeminal nerve; it,

along with the backof the head and

much of the neck, is

supplied by cervical

nerves C2 and C3.


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Central ConnectionsCentral Connections

The unipolarsomatic

sensory cells of the

trigeminal nerve do nothave their cell bodies

located in the central

nervous system.

Instead, they are found in

the trigeminal ganglion in

the same way that the cell

bodies of spinal somaticsensory cells are located

in the dorsal root ganglion

of a spinal nerve.Modified from Grays Anatomy, Longmans, London, 38th Ed 1989

p. 1107


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The fibres terminate

in the only nuclei for

general sensation inthe brainstem, the

spinal nucleus and

the chief sensory

nucleus.

Modified from Grays Anatomy, Longmans, London, 38th Ed 1989 p. 953


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Proprioceptive fibres are

important in various reflex

responses involving thejaws, and because they

need to be able to act very

fast, these are the only

peripheral sensory cells in

the body whose cell bodies

are located within the

central nervous system.They lie in the

mesencephalic nucleus.


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Motor cells of the

trigeminal nerveoriginate in the

trigeminal motor

nucleus.

Modified from: From Grays Anatomy, Longman, London, 38th

Edition, 1989. p 953.


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The Ophthalmic Division (V1)


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Ophthalmic Division (V1)Ophthalmic Division (V1)

The ophthalmic division, or V1 as it is commonly known (for

division "1" of "V", the fifth cranial nerve), is purely a sensory

nerve. It contains no somatic motor fibres at all.



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V1 OriginsV1 Origins

It originates in and

around the orbit andforms three main

branches, which pass

into the cranium

through the superior

orbital fissure, and join

up with each other to

run in the lateral wallof the cavernous sinus

with three other cranial

nerves (III, IV and VI).Grays Anatomy, Longmans, London, 38th Ed 1989 p. 803


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V1 BranchesV1 Branches

There are three major peripheral branches of this nerve, and

each of those has several further branches:

Frontal Nerve

Lacrimal Nerve

Nasociliary Nerve


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The frontal nerve runs

across the top of the

orbit, and as it comescloser to the face, it

divides into two major

branches.

These are the

supraorbital nerve and

the supratrochlear

nerves.

Grays Anatomy, Longmans, London,

38th Ed 1989 p. 1098



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38th Ed 1989 p. 1098

The supraorbital nerve

emerges onto the face

through thesupraorbital foramen

(sometimes this is just

a notch rather than afull-blown foramen),

and runs up onto the

forehead to supply the

tissues of theforehead and scalp.



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The supratrochlear

nerve runs more

medially and emerges

from the orbit close toits medial edge.

Here it runs up to

supply the medialportion of the upper

eyelid and the skin of

the forehead and scalp

towards the medial

aspect of the forehead

and the skin above the

root of the nose.



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38th Ed 1989 p. 1098

The lacrimal nervesupplies the

conjunctiva and skin of

the lateral side of the

upper eyelid and the

lacrimal gland with

common sensation.

The secretomotor

nerves to the lacrimal

gland are passed to

the lacrimal nerve fromthe maxillary division

of the trigeminal nerve.



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Hence the statement that the ophthalmic nerve is purely a

sensory nerve remains correct. It simply receives

communication from another source, but the motor nerves do

not originate with the ophthalmic nerve.




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In fact, they do not even originate with the trigeminal nerve, but

instead with the facial nerve (VII) via the greater superficial

petrosal nerve and the pterygopalatine ganglion.

This is a phenomenon to which we will become used - the

ability of certain groups of nerve fibres to "hitch a ride" with any

passing nerve trunk that is convenient and is heading in the

correct direction.



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Grays Anatomy, Longmans, London,38th Ed 1989 p. 1098

The nasociliary nerve

supplies the more medial

structures associated

with the orbit.

These include the lining

membranes of the

sphenoidal and ethmoidalsinuses, the tissues of

the roof of the nose and

the skin over the front of

the nose down as far as

its tip.



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You should make

an effort to

understand how the

nerves that radiatefrom the orbit

beneath the skin

contribute to the

pattern of

cutaneous nerve

sensation in the

area supplied byV1.

Modified from: Evers H &

Haegerstam G. Introduction to

Dental Local Anaesthesia.,

Mediglobe SA, Fribourg, 2nd Ed.1990, p. 12.



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The Maxillary Division (V2)


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The maxillarydivision of the

trigeminal nerve,

often known simply

as the maxillary

nerve, also contains

only sensory fibres.

Modified from Grays Anatomy,

Longmans, London, 35th Ed 1973

p. 1005

The Maxillary Division (V2)The Maxillary Division (V2)


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The nerve originates

from the trigeminal

ganglion as itsintermediate branch,

lying between those of

V1 and V3.

It runs forward in the

middle cranial fossa in

the lateral wall of the

cavernous sinus andpasses out of the

cranium through

foramen rotundum. Modified from Grays Anatomy, Longmans, London, 38th Ed 1989p. 1107



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Just before it runs through the foramen, it gives off a smallbranch to supply the dura mater of the middle cranial fossa.



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Once it enters foramen

rotundum, it passes

through the bone toemerge in the

pterygopalatine fossa.

Illustrated Handbook in Local Anaesthesia,

Ed: E. Eriksson, Munksgaard, Denmark,

1969, p.66.



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When it reaches the pterygopalatine fossa, it gives off a

number of branches.




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Lying inferior to the nervetrunk is a parasympathetic

ganglion called the

pterygopalatine ganglion.

Two branches from the nerve

pass towards this, and

subsequently continue

through the ganglion to formfurther branches within the



Longmans, London, 35th Ed 1973 p. 1005



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The main trunk of the nerve,

however, continues anteriorly

to run through the inferior

orbital fissure (be sure youunderstand how this relates to

the pterygopalatine fossa by

looking at a skull), and

changes its name to theinfraorbital nerve.





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It sinks down into a depressed

groove in the orbital surface of

the maxilla where it often gives

off a middle superior dental

nerve, and this groove

eventually roofs over to formthe infraorbital canal.

The nerve runs through this

canal, and eventually emerges

on the facial surface of the

maxilla through the infraorbital

foramen.Modified from Grays Anatomy,




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Here it gives of branches to

the upper lip, lower eyelid

and the side of the nose.

In the canal, the infraorbital

nerve gives off the smallanterior superior dental

nerve, the nerve supply to

the upper anterior teeth,

running in canaliculus

sinosus.





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The branches of the maxillary nerve in the pterygopalatine

fossa include:

posterior superior dental nerves

palatine nerves

sphenopalatine nerves (nasal nerves)

pharyngeal nerves

zygomatic nerve



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The Posterior Superior Dental NervesThe Posterior Superior Dental Nerves

The posterior superior dentalnerve ornerves (there are

usually several) contribute to

the nerve supply of the upper

teeth.

They run downwards on the

back of the maxilla and pass

into the bone through aseries of small foramina.

Modified from Grays Anatomy, Longmans,

London, 35th Ed 1973 p. 1005


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Here they run into the body of

the maxilla, and reach the

lining tissue of the maxillarysinus which they supply with

sensory nerve endings.

From here, the fibres aredistributed further to form the

molar part of the nerve plexus

that supplies the upper teeth.

This is known as the superior

dental nerve plexus.



SS


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Small nerve twiglets are also supplied to the gingivae on the

buccal aspect of the molar teeth, and also to the superior

portion of the cheek in the molar area.

Because the same nerves that supply the teeth also supply the

maxillary sinus lining, the pain of maxillary sinusitis is often

referred to the upper teeth, especially in the premolar area.


Th P l ti NTh P l ti N


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The Palatine NervesThe Palatine Nerves

The palatine nerves, as their names imply, provide somaticsensory nerve supply to the palate, and parasympathetic

secretomotor nerves to the minor salivary glands contained in

the palatal mucosa.The somatic fibres originate at first in the branches of the

maxillary nerve that extend into the pterygopalatine ganglion,

and emerge from this without having synapsed, because they

are somatic sensory nerve fibres which do not synapse along

their length.



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While the fibres that will become the palatine nerve are in theganglion however, some post-ganglionic parasympathetic

secretomotor fibres from the ganglion get picked up and run

with them to be distributed to the minor salivary glands. The

nerve also contains some taste fibres.

Modified from

Grays

Anatomy,

Longmans,

London, 35th

Ed 1973 p.

1006



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Modified from

Grays

Anatomy,

Longmans,

London, 35th

Ed 1973 p.

1006

Some branches of the palatine nerve emerge through thelesser palatine foramina in the palatine bones, and these are

termed the lesser palatine nerves. They provide taste fibres,

secretomotor fibres and common sensation to the tissues of the

soft palate.



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Modified from

Grays

Anatomy,

Longmans,

London, 35th

Ed 1973 p.

1006

The remainder pass through the greater palatine foramen andbecome the greater palatine nerves, running forwards in the

palate to approximately the level of the canine tooth, where they

meet and anastomose with the fibres of the long

sphenopalatine nerve.

Th P l ti NTh P l ti N


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Because the palatal tissues are supplied by these nerves, weneed to anaesthetize them if we wish to extract a palatal tooth,

because otherwise the palatal gums will remain sensitive.

The Sphenopalatine NerveThe Sphenopalatine Nerve


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The sphenopalatine nerve passes medially into the

sphenopalatine foramen, which lies in the deepest part of the





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After passing through the foramen, the nerve gives off some

small lateral branches (short sphenopalatine nerves) which are

distributed over most of the lateral wall of the nasal cavity.



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The long sphenopalatine or nasopalatine nerve crosses the roof

of the nasal cavity and descends on the nasal septum to supply

the overlying mucous membrane.




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The nerve continues through the incisive canal to communicate

with the greater palatine nerves. Small twigs help to supply the

palatine supporting structures of the central and lateral incisors.

Modified from: Illustrated

Handbook in Local

Anaesthesia, Ed: E.

Eriksson, Munksgaard,Denmark, 1969, p.66.

The Pharyngeal NervesThe Pharyngeal Nerves


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The Pharyngeal NervesThe Pharyngeal Nerves

The pharyngeal nerves supply the mucous membrane of the

upper nasopharynx.


The Zygomatic NerveThe Zygomatic Nerve


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The zygomatic nerve runs

into the orbit through the

inferior orbital fissure like the

infraorbital nerve, but instead

of running across the floor of

the orbit, it runs on the lateral

wall on the zygomatic bone,from which it takes its name.

It also picks up some fibres

from the pterygopalatineganglion.



p. 1005



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It divides into two branches, the zygomaticotemporal nerve

and the zygomaticofacial nerve which run into the zygomaticbone through two small foramina, and these emerge through

foramina which take the names of the nerve branches.



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The parasympathetic secretomotor fibres from thepterygopalatine ganglion travel in this branch of the nerve, and

they run to the lacrimal nerve of V1, travelling along it to the

lacrimal gland, and constitute most of its parasympathetic

secretomotor innervation.

Lacrimal Branch

Modified from

Grays Anatomy,

Longmans,

London, 35th Ed

1973 p. 1005

The Infraorbital NerveThe Infraorbital Nerve


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The Infraorbital NerveThe Infraorbital Nerve

The important

branches of the

infraorbital nervewithin the orbit are

the middle superior

dental nerve and the

anterior superiordental nerve, which

contribute to the

superior dental

plexus.



p. 1005

Upper Teeth Nerve SupplyUpper Teeth Nerve Supply


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As we haveseen, the nerve

supply to the

dental pulps of

the upper teethand the nerve

supply to the

maxillary sinus

are closelyrelated.

http://www.septodont.ca/Septodont/english/other/cea_di01.html



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Uppe eet e e Supp yUppe eet e e Supp y

The superior

dental plexus isformed by

twiglets from the

posterior superior

dental nerve, theanterior superior

dental nerve, and

the middle

superior dentalnerve when it is

present.

http://www.septodont.ca/Septodont/english/other/cea_di01.html



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pp pp ypp pp y

When the middle superior dental nerve is present, fibres fromthe posterior superior dental nerve supply the molar teeth and

a twig to the second premolar.

The middle superior dental nerve fibres supply themesiobuccal root of the upper first molar, the premolars, and

may jointly supply the canine tooth.

The anterior teeth as far back as the first premolar have

twiglets from the anterior superior dental nerve.



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pp pp ypp pp y

When the middle superior dental nerve is not present, then

the upper posterior teeth as far back as the second premolarare supplied with twiglets by the posterior superior dental

nerve, and anterior teeth as far back as the second premolar

are supplied by the anterior superior dental nerve.



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pp pp ypp pp y

There is no difference in the degree of sensitivity of the teeth

regardless of the presence or absence of the middle superior

dental nerve.

The adjacent buccal gingivae are supplied by the same nerves

that supply the dental pulps of the adjoining teeth.

Upper Teeth AnaesthesiaUpper Teeth Anaesthesia


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If pulpal anaesthesia is required, for example for a filling, then

anaesthesia of these nerves is all that is required.

If anaesthesia is required for extraction, however, then thenerve supply of the palatal tissues must also be

anaesthetized, since these will be surgically detached during

the procedure.


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The End

trigeminal nerve v1 & v2 slides

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