Trigminal Nerve V3 Slides

7/27/2019 Trigminal Nerve V3 Slides

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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

Trigeminal Nerve: V3Trigeminal Nerve: V3


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Mandibular Division V3Mandibular Division V3

Recall the area

supplied with

sensory innervation

by the mandibular

division of the

trigeminal nerve

(V3).

Grays Anatomy, Longmans, London,

38th Ed 1989 p. 1106


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The mandibulardivision of the

trigeminal nerve,

often known simply

as the mandibularnerve, contains both

sensory fibres and

motor fibres.

Modified from: Evers, H & Haegerstam, G.

Introduction to Local Anaesthesia, Mediglobe SA,

Fribourg, 2nd Edition 1990. P. 60



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The sensory portion of

the mandibular nerve

passes into thetrigeminal ganglion and

from there to the

brainstem along with

the sensory fibres fromV2 and V1.

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



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The somatic motornerve fibres leave the

pons in a separate

motor root, which joins

the main trunk of themandibular nerve just

after it exits the

cranium throughforamen ovale in the

greater wing of the

sphenoid bone.



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Here it forms a common

trunk for a very short

distance, before givingoff its first branch.


Introduction to Local Anaesthesia,

Mediglobe SA, Fribourg, 2nd

Edition, 1990.P. 60

Mandibular Division V3


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This is a small twig

containing sensory fibres,

and it dives back into the

cranium with the middle

meningeal artery through

foramen spinosum of thesphenoid bone to supply

most of the dura mater

with sensation. It is known

as the recurrentmeningeal nerve, or

nervus spinosus.

Modified from Grays Anatomy, Longmans, London, 38th

Ed1989 p. 1105



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The common nervetrunk now gives off

small muscular

branches containing

motor fibres to thetensor palati and

tensor tympani

muscles, and the

medial pterygoid

muscle.

Modified from Grays Anatomy, Longmans, London, 38th Ed 1989

p. 1105



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It also acquires smallcommunicating

branches from the

otic ganglion, a

parasympatheticmotor ganglion which

lies deep to it in the

infratemporal fossa.


p. 1105



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The nerve now divides into a larger posterior division and a

smaller anterior division. A general (and inaccurate) rule:

The posterior division is entirely composed of sensorybranches except for one motor one.

The anterior division comprises entirely motor branches

except for one sensory one.



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Posterior DivisionPosterior Division


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Posterior DivisionPosterior Division

The branches of the posterior division of the

mandibular nerve are:

Auriculotemporal nerve (sensory)

Inferior dental nerve (sensory)

Lingual nerve (sensory)

Nerve to mylohyoid and anterior belly of digastric (motor)


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Auriculotemporal NerveAuriculotemporal Nerve


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The auriculotemporalnerve or nerves are

important because it is

the sensory nerve to

the TMJ and carries

secretomotor fibres

from the otic ganglion

to the parotid gland.



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It leaves the main trunk of

the mandibular nerveshortly after the motor root

attaches to it, and passes

posteriorly towards the

middle meningeal artery.

It splits into two, the two

branches pass around the

middle meningeal arteryand circle it, and then they

join up again to form a

single branch.Modified from Grays Anatomy, Longmans, London, 38th Ed 1989

p. 1105



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p. 1105


It continues to runposteriorly, lying on the

tensor palati muscle,

and reaches the deep

aspect of the neck of themandible past which it

runs, between the bone

and the

sphenomandibularligament.


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p. 1105


It then curves around

behind the

temporomandibular jointwhich it supplies with

sensory fibres and runs

into the parotid salivary

gland.


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It gives off sensory and parasympathetic secretomotor fibres

acquired from the otic ganglion to the gland, and then curves

to run superiorly in the gland, and terminates in the superiortemporal branches, which supply common sensation to the

skin and underlying structures in the posterior temple area and

the side of the scalp.



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Inferior Dental NerveInferior Dental Nerve


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Modified from: Evers, H & Haegerstam, G. Introduction to

Local Anaesthesia, Mediglobe SA, Fribourg, 2nd

Edition,1990. P. 60


The inferior dental nerve, also

known as the inferior alveolarnerve, is of great importance

because it provides the

sensory nerve supply to the

pulps of the lower teeth.

To do so, it must enter the

body of the mandible.


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It does this by passing through the

mandibular foramen on the internal

surface of the mandibular ramus,

and running in the inferior dental

canal.


Local Anaesthesia, Mediglobe SA, Fribourg, 2nd

Edition,1990. P. 60



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Initially, the nerve lies in the mandibular canal as a single trunk,

but soon divides into numerous smaller branches which form a

plexus within the body of the mandible.


From Shigeru Tajiri, An Atlas of Anatomy of the Head and Neck, Aproman 1998


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J.M. Sanchis, Miguel Penarrocha, and F. Soler, Bifid

Mandibular Canal. J Oral Maxillofac Surg 61:422-424, 2003

Purpose: To determine the incidence and characteristics of bifidmandibular canals.

Methods:A retrospective study was performed using panoramicradiographs of 2012 patients subjected to dental treatment in the Dental

Clinic of the Valencia University Dental School (Valencia, Spain) between1996 and 1999. The goal was to investigate the presence of double

mandibular canals.

Results: The extraoral panoramic radiographs revealed a total of 7 imagessuggestive of bifid canals. Mandibular computed tomography revealed the

existence of this anatomic variant in 2 of 3 patients. An analysis wasperformed on the incidence of this type of image in extraoral panoramic

radiography, itspossible interpretations, and the clinical implications of bifid mandibular

canals.

Conclusions: In this study, 0.35% of canals were bifid. All cases were in

women.


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The nerve suppliesthe pulps of the lower

teeth and their

periodontal

ligaments, the

mandibular bone, and

the labial gingivae

and buccal gingivaeback about as far as

the second premolar.


Evers, H & Haegerstam, G. Introduction to Local Anaesthesia, Mediglobe SA, Fribourg, 2nd Edition, 1990. P. 85


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While in the body of the

mandible, the nervesplits into two branches.

Grays Anatomy, Longmans, London, 38th Ed 1989 p. 1101



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One of these continues

forwards in the body of

the mandible to supplylabial gingivae and

pulps of the lower

anterior teeth, and it is

known as the incisivenerve, or more

correctly, the incisive

plexus, because it hasceased to be a single

nerve trunk by this

stage.




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The other exits the

mandible through asmall backwards-

directed foramen in the

external surface of the

body of the mandible

called the mental

foramen, usually found

between the roots of thelower first and second

permanent premolar

teeth.




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This branch is called the

mental nerve, and it

supplies commonsensation to the lower

lip and the front of the

chin.




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Nerve to the MylohyoidNerve to the Mylohyoid


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The nerve to the mylohyoid

muscle and anterior belly of the

digastric branches off from theinferior dental nerve just before

it passes into the mandibular

foramen.

It is the only motor branch of

the posterior division, which is

why it supplies muscles instead

of other tissues.


Local Anaesthesia, Mediglobe SA, Fribourg, 2nd Edition,

1990. P. 60


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Frommer and colleagues,however, showed that

histologically, the mylohyoid

nerve contains both sensory

and motor nerve fibres.



1990. P. 60

Frommer, J, Mele, FA, & Monroe, CW. 1972.

The possible role of the mylohyoid nerve in

mandibular posterior tooth sensation. J.

American Dental Assoc. 85, 113-117.



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Other studies have shown that

it may pass through small

lingual foramina in the mandible

with varying frequency in the

anterior and premolar regions.


Local Anaesthesia, Mediglobe SA, Fribourg, 2nd Edition,1990. P. 60

(Madeira, MC, Percinoto, C, & Silva, M. 1978.

Clinical significance of supplementaryinnervation of the lower incisor teeth: a

dissection study of the mylohyoid nerve. Oral

Surg. 46: 608-614.

Wilson, S, Johns, P, & Fuller, PM. 1984. The

inferior and mylohyoid nerves: an anatomicstudy and relationship to local anaesthesia of

the lower anterior teeth. J American Dental

Assoc. 108: 350-352).



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If the nerve branches from the

main trunk of V3 high enough in

the infratemporal fossa to avoid

being bathed in anaesthetic

solution, then such patientsmay show signs of successful

anaesthesia and still show

sensitivity when dental

procedures are undertaken.



1990. P. 60



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Bennett and Townsend have

shown that the mean height of

the nerve branch in their seriesof 6 dissections was 13.4 mm

with a maximum height of 20.7

mm, high enough in some

cases to avoid anaesthesia witha conventional block.



1990. P. 60

(Bennett S and Townsend G. Distribution of the

mylohyoid nerve: anatomical variability andclinical implications. [online].Aust Endod J,

2001 Dec; 27 (3): 109-11).



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This would seem to suggest a

possible accessory nerve

supply for anterior and premolar

mandibular teeth.

Additional anaesthesia of the

mylohyoid nerve can be

obtained with a lingualinfiltration injection in the

premolar region.



1990. P. 60

(Bennett S and Townsend G. Distribution of the

mylohyoid nerve: anatomical variability and

clinical implications. [online].Aust Endod J,

2001 Dec; 27 (3): 109-11).



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Indeed, Sillanpaa and

colleagues anaesthetized the

mylohyoid nerves of volunteerdental students and in 21%

reported obtaining partial

anaesthesia of the lower teeth,

including the first mandibular

molar.



1990. P. 60

(Sillanpaa M, Vuori V & Lehtinen R. The

mylohyoid nerve and mandibular anaesthesia.Int J Oral Maxillofac Surg. 1988 Jun; 17(3): 206-

207).



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A specific cutaneous sensory

branch of this nerve supplying

an area of the chin has recently

been recognized.



1990. P. 60

(Hwang K, Han JY, Chung IH & Hwang SH.

Cutaneous sensory branch of the mylohyoid

nerve. J Craniofac Surg. 2005 May; 16(3): 343-345 (Discussion 346)).



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Lingual NerveLingual Nerve


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The lingual nerve leaves the

anterior aspect of the main

trunk of the posterior division

well above the mandibular

canal, and runs parallel to the

inferior dental nerve for aconsiderable distance.

It often goes numb when the

inferior dental nerve isanaesthetized.


Introduction to Local Anaesthesia, Mediglobe

SA, Fribourg, 2nd Edition, 1990. P. 60

Li l NLi l N


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It comes to lie a little deeper

than the inferior dental nerve

though, and does not runinto the mandible.

Li l NLi l N


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Instead, it curves gently above the mylohyoid muscle, passingbetween the body of the mandible and the duct of the

submandibular gland to pass beneath the duct, rising again

medially to terminate in the substance of the anterior part of the

tongue.

Netter, F.

1989,

Atlas of

Human

Anatomy,

Summit,

New

Jersey,

Ciba-

GeigyMedical,

Plate 53.

Li l NLi l N


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The lingual nerve is the

major sensory nerve of

the anterior two-thirds of

the tongue, and thereforealso carries the special

sensation of taste, as well

as common sensation.







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It also supplies common

sensation to the tissues ofthe floor of the mouth, and

to the lingual gingival

tissues.

It must therefore be

anaesthetized if extraction

of a lower tooth is required.







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It is commonlyanaesthetized along

with the inferior dental

nerve during the

inferior dental nerve

block.

Modified from: Haglund, J. & Evers, H Local

Anaesthesia in Dentistry, Astra Lkemedel

Sdertlje, 2nd Edition, 1975. p. 52.




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Grays Anatomy, Longmans, London, 38th

Ed 1989 p. 1101


During its path as it

descends towards the

mylohyoid, it picks up asmall branch called the

chorda tympani, which

carries secretomotor

parasympathetic fibres

which it distributes to the

submandibular and

sublingual salivary glands,as well as to minor salivary

glands in the floor of the

mouth.



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These are preganglionic

fibres initially, and they

synapse in the

submandibular ganglion

which is located just inferior

to the lingual nerve close to

the submandibular gland.

The postganglionic fibres

pass to the submandibular

gland and some hook a ridewith the continuing lingual

nerve to reach the

sublingual gland.


Grays Anatomy, Longmans, London, 38th

Ed 1989 p. 1101

Accessory Nerve SuppliesAccessory Nerve Supplies


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The lingual nerve can often provide accessory innervation to

anterior teeth, as can small branches from the ascending

branch of the transverse cutaneous nerve of the neck.

Depositing a small amount of anaesthetic lingually (with

aspiration to avoid intravascular injection) will often solve the

problem.



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McGeachie JK. Anatomy of the lingual nerve in relation topossible damage during clinical procedures. Ann R

Australas Coll Dent Surg. 2002 Oct;16:109-10.

Oral Health Centre of Western Australia. [email protected] to the lingual nerve, resulting in transient or permanent

paraesthesia or anaesthesia, is a common undesirable complication ofsurgical interventions to the lower third molar region. The anatomy of thenerve, as it travels from its origin high in the infra-temporal fossa, to the

floor of the mouth is quite variable. The most critical part of its course iswhere it enters the sublingual region just alongside the lingual alveolar

plate of the lower third molar.

A significant number of lingual nerves are located above the alveolar

bone in the gingival tissues, or very close to the bone. Retraction ofthe lingual mucosa can lead to lingual nerve trauma. There is no doubt thatthe lingual nerve is extremely vulnerable in this region and clinicians must

assume that it is closely adjacent to the lingual region of the lower thirdmolar, in all cases, in order to minimize possible damage.


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Anterior Division of V3Anterior Division of V3

Anterior Division of VAnterior Division of V


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Anterior Division of V3Anterior Division of V3

The branches of the anterior division of the

mandibular nerve are:

Nerves to masseter (motor)

Nerves to temporalis (motor)

Nerve to lateral pterygoid (motor)

Nerve to medial pterygoid (motor)

Buccal nerve (Sensory)

Buccal NerveBuccal Nerve


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The buccal nerve,sometimes known as the

long buccal nerve (especially

in oral surgery), is the

source of common sensationto most of the cheek and the

buccal gingival tissues of the

lower posterior teeth.






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It must therefore

also be

anaesthetized if alower posterior

tooth is to be

extracted.

Modified from: Haglund, J. &

Evers, H Local Anaesthesia in

Dentistry, Astra Lkemedel

Sdertlje, 2nd

Edition, 1975. p. 53.

Nerve Supply to Lower TeethNerve Supply to Lower Teeth


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Pain sensation to the dental pulps of the lower teeth and

common sensation to buccal and labial gingival tissues is

supplied by the inferior dental nerve.

Therefore, any procedure that requires anaesthesia of the

pulps of any lower tooth can be performed successfully if the

inferior dental nerve is blocked.



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We try to anaesthetizeit just before it enters

the mandibular

foramen, and this

ensures that tooth

pulps along the whole

of the anaesthetized

side remain numb.







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Because there is some

crossing over of nervesupplies from the right

and left inferior dental

nerves near the

midline, sometimes

infiltration anaesthesia

is also required in this

area.


Modified from: Evers, H & Haegerstam,

G. Introduction to Local Anaesthesia,

Mediglobe SA, Fribourg, 2nd Edition,

1990. P. 87



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If anaesthesia is required for extraction, however, then the

nerve supply of the gingival tissues must also beconsidered. The lingual nerve can be blocked to ensure

anaesthesia of the lingual gingivae.



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Posteriorly, the buccal gingivae are supplied by the buccal

nerve, and this must therefore also be anaesthetised for

extractions in this region.For premolar and anterior teeth, the buccal and labial gingivae

are supplied by the inferior dental nerve, and they will

therefore have been successfully anaesthetised already by an

inferior dental nerve block.


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Difficulty in anaesthetizing palatal teeth is most commonly due

to accessory innervation of those teeth by branches of the

greater palatine nerve or from the terminal branches of the long

sphenopalatine nerve.Injection of a small amount of anaesthetic palatally will normally

secure anaesthesia. Other techniques such as intra-ligamental

or intraosseous injections may also be useful, as may newer

methods of anaesthetic delivery such as the wand.



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Difficulty in anaesthetizing mandibular teeth is most commonly

encountered in the molar area.

It it recognized that the long buccal nerve, lingual nerve,

mylohyoid nerve, and branches of the inferior dental nerve may

all contribute to such problems. In addition, sensory fibres from

the muscles of mastication may also provide an accessory

innervation to these teeth.



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Problems due to the long buccal nerve can be overcome by

administering a buccal block injection.



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Those from the mylohyoid nerve or from accessory innervation

from muscles of mastication can usually be solved by injecting

into the floor of the mouth between the submandibular fold andthe mandible, taking care not to inject intravascularly, especially

into the facial artery. Inject through the mylohyoid muscle.



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The cortical bone here is sometimes porous and thin enough to

allow diffusion of anaesthetic into the bone to anaesthetize

accessory nerve bundles from the muscles of mastication.

Copyright

A. Forrest

2004



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The lingual nerve can often also provide accessory innervation

to anterior teeth, as can small branches from the ascending

branch of the transverse cutaneous nerve of the neck.

Depositing a small amount of anaesthetic lingually (with

aspiration to avoid intravascular injection) will often solve the

problem.


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Why is dental pulpal pain difficult to localize?The pulp contains only pain fibres (A-delta and C fibres),

therefore touch, temperature and pressure are only perceived

as pain. Any potentially damaging stimulus will cause

changes to the fluid in the dentinal tubules.

This pain is difficult to localize unless the inflammation

extends to the periodontal ligament where additional sensory

receptors (pressure, proprioception) give further information.


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In addition, the numerous pain fibres of the pulp converge onto

fewer fibres in the brainstem and information about the specific

tooth is lost.

Dental pain can be referred from one arch to the other arch,

but it never crosses the midline. It may also be referred to the

ear, neck etc.

Dental pain may sometimes be a pain referred to the teeth

from a non-odontogenic source e.g. sinuses, heart.

The only way to ensure accurate diagnosis of dental pain is by

thorough history taking, examination and testing.



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The following resources might be useful to you:

A good page on LA techniques is found at:

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

For a discussion on accessory foramina and innervation in themandible, see:

http://dmfr.birjournals.org/cgi/reprint/29/3/170.pdf

For a recent American discussion of LA in Dentistry, see:

http://www.cda.org/member/pubs/journal/jour0503/budenz.htm


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