TRIGEMINAL NERVE

PRESENTED BY: T.ASHA PRAVEENA

NERVOUS SYSTEMCentral Peripheral

NEURON Structural & Functional unit

CLASSIFICATION OF NERVE FIBERSType A (myelinated) Alpha Beta Gamma Delta Type B Type C(Non myelinated)

Central nervous sys -brain & spinal cord Peripheral NS-somatic & autonomic nerves Autonomic-sympathetic & parasymapathetic Somatic-Spinal & cranial

There are 12 pairs of cranial nerves

Trigeminal nerve:N trigeminus / 5 th /tri-facial nerve Largest cranial nerve ORIGIN: Emerges from side of pons , near its upper border gives both sensory (head and face) Contains about 170,000 fibers motor (muscles of mastication) Contains about 7700 fibers by pennisi et al 1991 So in short its a mixed nerve

Supply:

Sensory : Face, greater part of the scalp, teeth , oral and nasal cavity, duramater and cerebral blood vessels. Motor: Masticatory muscle, anterior belly of diagartric, mylohyoid.

Conveys variety of impulses

Exteroceptive impulses of touch, pain, and thermal senses are transmitted from skin of face, forehead, mucous membrane of nasal cavity, oral cavity, floor of mouth and anterior 2/3 rd of tongue Proprioceptive impulses (deep pressure) are conveyed from teeth periodontium, hard palate and TMJ receptors

Special visceral efferent fibres innervate muscles of mastication, tensor tympani, tensor veli palatine muscles, efferent the motor root (portio minor) Afferent fibres constitute the sensory root (portio major)

GanglionAny group of nerve cell bodies in central or peripheral nervous system Aggregations of the cell bodies of neurons may also be found out side the central nervous system, such aggregations are referred to as ganglion.

Semi lunar /semilunare (gasseri) /gasserian ganglion

Occupies cavum meckelli (cavity) in duramater near the apex of petrous part of temporal bone Crescent shaped. Axons of unipolar cells thats present in the ganglion divide into peripheral and central branches Peripheral fibers ophthalmic and maxillary nerve and sensory root of mandibular nerve Central branch constitutes fibers of sensory root which enters the pons

Structure surrounding the ganglionMedially: Internal carotid artery, posterior part of cavernous sinus Laterally: Posterior end of zygomatic arch Inferiorly: Motor root of the nerve itself, greater petrosal nerve, apex of petrous temporal bone, foramen lacerum, carotid artery in its bony canal

Origin: sensory rootaxons of cells of trigeminal / semi lunar ganglion lies in Meckels cave of duramater covering the trigeminal impression near the apex of petrous part of temporal bone on entering pons sensory fibres runs towards Principal sensory nucleus Before reaching 50% of fibres divides into 1) Ascending 2)Descending branches and remaining 50% either ascending or descending without division

Developmental aspects of sensory rootMedullation of fibres of sensory root begins about 5th month of foetal life and completes until the 3rd month after birth.

SENSORY ROOT OF THE TRIGEMINAL NERVE

Sensory nucleiMESENCEPHALIC NUCLEUS -The fibres carry the proprioceptive impulses from masticatory muscles,teeth,facial & ocular muscles. -It is a relay for jaw jerk reflex

PRINCIPAL SENSORY NUCLEUS -Considered to be mainly concerned with tactile & pressure stimuli.SPINAL TRIGEMINAL NUCLEUS -most caudal nucleus of the trigeminal nerve.

Motor rootOvoid, contains large multipolar cells interspread with small multipolar cells. Origin : Arises from two nuclei. 1) Superior. 2)Inferior or chief nucleus.

MOTOR ROOT OF THE TRIGEMINAL NERVE

Schematic presentationMotor root origin Motor nucleus, located in the upper Pons passes along the medial aspects Semi lunar ganglion passes through Foramen ovale joins mandibular division, immediately below the base of skull Mainly supplies the muscles of mastication and is called masticator nerve

Motor nucleus: Receives afferents from sensory nuclei; mesencephalic nucleus; reticular formation ; and these represent pathways by which salivary secretion and mastication may be co- ordinated.

Division of trigeminal nerve

Trigeminal nerve

Ophthalmic nerve

Maxillary nerve

Mandibular nerve

Trigeminal nerve:

Ophthalmic contains 26000 myelinated fibers maxillary nerve contains 50,000 mandibular nerve contains 78,000

Trigeminal nerve and its branches

Three division of the main nerve is associated with 4 small ganglionCiliary ganglion: Associated with ophthalmic nerve Sphenopalatine ganglion: Associated with maxillary nerve Otic ganglion and Sub maxillary ganglion : Associated with mandibular nerve

All these four ganglion receivesSensory filaments of trigeminal nerve Motor and Sympathetic filaments from various sources

These filaments are called as ROOTS OF GANGLION

OPTHALMIC NERVE

Ophthalmic nerve1st division of T-Nerve. Superior and smallest division. Purely sensory, arises from upper part of semi lunar ganglion as short flat band, 2.5 cms long, passing forward in the lateral wall of cavernous sinus. Before entering the orbit by superior orbital fissure, divides into

Ophthalmic nerve

lacrimal

Frontal

nasociliary

this nerve is also joined by internal carotid sympathetic plexus and communicates with occulomotor, trochlear and abducent nerve

Supplies:Eyeball, lacrimal gland and conjunctiva. Part of nasal mucosa. Skin of nose , eyelids, forehead, and part of scalp.

1)Lacrimal nerveSmallest of the branch Enter the orbit through lateral part of superior orbital fissure and runs along upper border of rectus lateralis with lacrimal artery Contains lacrimal secreto -motor fibers and supplies lacrimal gland and adjoining conjunctiva It pierces orbital septum and ends in upper eyelid and joins filaments of facial nerve

Lacrimal nerve

2)Frontal nerveLargest branch Enters the orbit through Superior orbital fissure above annular tendon (of zinn) Proceeds b/w levator palpebrae superioris and periosteumBranches of frontal nerve 1)Supratrochlear nerve (small) 2)Supra orbital nerve (large)

Frontal nerve

i)Supratrochlear nerveIt emerges between trochlea and supraorbital foramina, finally carving up on fore head Supplies: Conjunctiva, upper eyelids skin, skin of lower forehead near the midline

1)Supratrochlear nerve

ii)Supra orbital nerveProceeds between levator palpebrae superioris and orbital roof and transverses supraorbital notch or foramen Supplies: Palpebral filaments of upper eyelid and conjunctiva it ascends to forehead and divides into a) Medial (smaller) b) Lateral branches ,supplying the Skin of scalp Small rami to the mucosal of frontal sinus and to pericranium

2)Supra orbital nerve

3)Nasocillary nerveEnters the orbit through Superior orbital fissure Branches are divided into those arising from the orbit, in the nasal cavity and on the face

A) Branches in the orbit1)

Long root of the ciliary ganglion, contain sensory fibers which pass thro.. the ganglion without synapsing and continue into the eye ball by means of the short ciliary nerves 2) Long ciliary nerves, usually 2 or 3 long ciliary nerves, distributed to the iris and corneas in addition they contains post ganglionic fibers from the superior cervical sympathetic ganglion 3) Posterior ethmoidal nerve, supplies ethmoidal and sphenoidal sinuses, frequently absent

Branches in the orbit

4)Anterior ethmoidal nerve, largest , appears for a short distance (in the anterior cranial fossa). Through the cribriform plate of ethmoidal bone it descends down to nasal cavity sub branches: a) Internal nasal branches, two in number i.e. medial and lateral, suppliesmucosa of nose b) External nasal branches, supplies- the lower half of the nose

5)Infra trochlear nerve: Smallest branch Appears on the face above medial angle of eye Supplies: Conjunctiva, lacrimal sac and caruncle, medial ends of eyelids and upper half of external nasal cavity.

B.Branches arising in the nasal cavity

These branches supply the mucous membrane lining the cavity.

C. Terminal branches of the ophthalmicdivision on the faceThese terminal branches course below the trochlear nerve to supply the sensory fibers to the skin of medial parts of both eyelids,lacrimal sac & caruncle & also supply the skin over the side of the bridge of the nose.

CILIARY GANGLION

It is autonomic ganglion lying in the posterior part of orbital cavity to the lateral side of optic nerve medial to the lateral rectus muscle. It has three roots. 1.Motor/short (preganglionic,parasympathetic root) 2.Sensory /long(postganglionic,sympathetic) 3.Sympathetic root.

CILIARY GANGLION

Ciliary ganglion

Maxillary nerveMaxillary nerve

MAXILLARY NERVE:Its intermediate division of trigeminal nerve Totally sensory COURSE: leaves the ganglion between the ophthalmic and mandibular nerve as a flat plexiform band,

passes across the cavernous sinus and transverse through foramen rotundum, becomes more cylindrical and compact

leads to pterygopalatine fossa

gives 2 ganglionic branches+ zygomatic and posterior superior alveolar nerve infraorbital canal as infraorbital nerve further progress

enters

divides to supply, ala of nose, lower eyelid, skin mucous membrane of cheek and upper lip

A)

Branches of maxillary nerve :

In cranial cavity: Middle meningeal nerve B) Ptergyopalatine fossa: 1)Zygomatic nerve -- zygomatico-facial nerve nerve -- Zygomatico-temporal nerve 2) Pterygopalatine (Sphenopalatine) nerves a)Orbital branches b) Nasal branches : -posterior superior lateral nasal branches -medial or septal branches palatine branches : -greater /anterior palatine nerves -middle palatine nerves -posterior palatine nerves3)Posterior superior alveolar branches

C) Infraorbital groove/canal --Middle superior alveolar nerve -- Anterior superior alveolar nerve D) Terminal branches on the face: --Inferior palpebral nerve --External/lateral nasal branches --Superior labial nerves

Branches of maxillary nerve

Branches arising from maxillary nerve

In cranial cavity Middle meningeal nerveAlso know as nervus meningeus medius Leaves near foramen rotundum It receives ramus from internal carotid sympathetic plexus and along with middle meningeal artery. supplies Duramater of middle cranial fossa.

In pterygopalatine fossaZygomatic nerveStarts in pterygopalatine fossa Enters the orbit through inferior orbital fissure

Divides into 2 branches1) Zygomatico -temporal branch 2) Zygomatico -facial branch

1) zygomatico -temporal branchSupplies : Skin of temple, it also communicates

with facial and auriculo temporal nerve.Supplies a ramus to lacrimal nerve which conveys parasympathetic post ganglionic fibers from pterygopalatine ganglion to the lacrimal gland.

2) zygomatico -facial branchEmerges on the face through the foramen in zygomatic bone Supplies: -Skin on the prominence of the cheek -Forms plexus with zygomatic branches of facial nerve and palpebral branches of maxillary nerve

In pterygopalatine fossa Pterygopalatine (Sphenopalatine) nerves two short nerve trunks that unite They areat pterygopalatine ganglion and are then redistributed into several branches They serve as important functional communications between ganglion and maxillary nerve They carry postganglionic secretomotor fibers to lacrimal gland

Branches of the Pterygopalatine ganglion

Branches of distribution of pterygopalatine nervesThree groups: 1) Orbital: 2 or 3 fine filaments, enters the orbit and supply the periosteum of the orbit and the mucous membrane of the posterior ethmoidal sinus and the sphenoid sinus 2) Nasal branches: divides into --posterior superior lateral branches --medial or septal branches

i)Posterior superior lateral branches

Transmit sensory impulse from the mucous membrane of nasal septum and posterior ethmoid sinus

ii)Medial or Septal branches

Transmits sensory impulses from mucous membrane over the vomer

3)Palatine branchesIt descends in the pterygopalatine canal and they divide into 3 strands 1)greater or anterior palatine 2)middle palatine 3)posterior palatine

i)greater or anterior palatine

Emerges on the hard palate by passing through greater palatine foramen and courses in the anterior direction between osseous hard palate and muco periosteum, supplies major part of hard palate and palatal gingiva In its course breaks up into numerous branches and extends forward to premaxillary palatine mucosa, which is also supplied by nasopalatine nerve

ii)middle palatine nerveEmerges from lesser palatine foramen Fibers are sensory to mucous membrane of soft palate

iii)posterior palatine

Emerges from lesser palatine foramen supplies the mucous membrane of tonsillar areas , thus sensory to tonsil

Superior alveolar (dental) nerves:3)Posterior Superior alveolar nerve: Leaves the maxillary nerve in pterygopalatine fossa, then pierces infratemporal surface of maxilla, descends under mucosa of maxillary sinus finally supplies molar teeth +upper gums and adjoining part of cheek

Alveolar nerve:

In infra orbital groove or canal1)Middle Superior alveolar nerve:Arises from infraorbital nerve, through the infraorbital grooves , runs to lateral wall of maxillary sinus ,this links up with superior dental plexus, supplies upper pre-molar teeth This nerve is variable, it may duplicate or triplicate or absent

2)Anterior Superior alveolar nerve

Arises from infraorbital nerve, descends down and transverses canalis sinuosus in the anterior wall of maxillary sinus , then passes medially towards the nose and divides into branches supplying incisors and canine teeth It assists in formation of superior dental plexus Gives off nasal branch which passes through inferior meatus to supply lateral wall and floor of nasal cavity Finally it emerges near the root of anterior nasal spine to supply adjoining part of nasal septum

Terminal branches on the side of the nose 1)inferior Palpebral nerve

Usually 2 in number Passes upwards and supply sensory to the skin of lower eyelid and the conjunctiva Join with facial and zygomatico - facial nerves near lateral canthus

2)External or lateral nasal branchesPass to the skin on the side of the face

3) superior labialUsually 3 in number and supplies the skin and mucous membrane of upper lip

External nasal nerve:

Autonomic ganglion associated with the maxillary division of the trigeminal nerve Sphenopalatine ganglion (pterygopalatine ganglion)Largest peripheral parasympathetic ganglian Placed deep in pterygo -palatine fossa near Sphenopalatine foramen Connected functionally with the facial nerve Majority of the branches of ganglion are maxillary division sensory fibers from the palatal nasal mucosa , pharynx and orbit , they pass through ganglion and enters the maxillary nerve through its ganglionic branches

Sphenopalatine

ganglion

MANDBULAR NERVE :

MANDIBULAR TRUNK

MANDIBULAR NERVE :

Largest division of trigeminal nerve Has large sensory root, which proceeds from foramen ovale and small motor root which passes under semi lunar ganglion and unite with sensory root just outside the skull The nerve passes immediately between the tensor veli palatine and the lateral pterygoid which later gives it branches

Supplies: -teeth and gums of mandible -Skin in the temporal region -part of the auricle including external meatus and tympanum - lower lip, lower part of face and muscles of mastication -mucosa of the anterior 2/3 rd of tongue and mucosa of the floor of the oral cavity

Division of the nerve

Divided into two groups i.e. branches from undivided and divided nerve Branches from undivided nerves 1)Nervus spinosus (meningeal branch): arises outside the skull and passes into the middle cranial fossa and supplies the dura mater and the mastoid cells2) Nerve to the medial pterygoid

Branch of motor root, passes to innervate internal pterygoid muscle, also gives off a branch to supply tensor tympani and tensor veli -palatine muscles through the otic ganglion

BRANCHES OF MANDIBULAR NERVE

Branches from the divided nerve 1) Anterior division: gives bothsensory branch i.e. buccal nerve and motor i.e. 1)massetric nerve 2)deep temporal nerve 3)lateral pterygoid nerves

Buccal nerve:

Course : Proceeds between 2 parts of lateral pterygoid, descends deep ,then anterior to the tendon of temporalis muscle, it then passes laterally in front of the masseter muscle to unite with buccal branches of the facial nerve Supplies skin over the anterior part of buccinator and the buccal mucous membrane, together with the posterior part of buccal gingivae

BUCCAL NERVE :

Massetric nerve

Passes laterally above the lateral pterygoid, it crosses the posterior part of the coronoid notch with the massetric artery and enters the deep surface of the masseter. It also supplies the TMJ

Deep temporal nerves

Usually an anterior and posterior branch passes above the lateral pterygoid to enter the deep surface of the temporalis and supplies the said muscle

Deep temporal nerve

Nerve to lateral pterygoid

Enters the deep surface of the muscle , it may arise separately from the anterior division or with the buccal nerve.

2)Posterior divisionLarger posterior division is mainly sensory but also carries motor components Branches : a) Auriculotemporal nerve b) lingual nerve c) inferior alveolar nerve

AURICULOTEMPORAL NERVE

a) Auriculotemporal nerve

Course: Arises by a medial and a lateral root unite behind the middle meningeal artery, it then passes posteriorly deep to the external pterygoid muscle and then between the sphenomandibular ligament and neck of condyle of the mandible

Branches of Auriculotemporal nerve1)Parotid nerve 2)Articular nerve 3) Auricular nerve 4) Meatal nerve 5)Terminal branches (superficial temporal)

Auriculotemporal nerve

1)Parotid nerve

Gives sensory, secreto -motor and vasomotor to the gland 1 or 2 twigs of sensory fibers pass from Auriculotemporal nerve and enters the posterior part of the temperomandibular joint

2)Articular nerve

3)Auricular branches

They supply the skin of the helix and tragus

4) Meatal nerve: They supply the skin lining the meatus and the tympanic membrane

5)terminal branches (superficial temporal accompany the superficial temporal artery, supply the skin of the temporal region and communicates with the facial and zygomaticotemporal nerves

Lingual nerve:

Origin: posterior trunk of the mandibular nerve ,lies at first between the tensor veli palatine and the lateral pterygoid where it is joined by chorda tympani branch of the facial nerve and frequently by a branch of inferior alveolar nerve Emerging from the under cover of lateral pterygoid proceeds forward and downward between ramus of mandible and medial pterygoid, lying anterior to and slightly deeper than the inferior alveolar nerve

..It then lies on the deep surface of the mandible on the medial side of the roots of the mandibular third molar where it is only cover by the mucous membrane of gums and can be pressed by the finger placed inside the mouth in the pterygomandibular space, lingual nerve lies parallel to the inferior alveolar nerve but medial and anterior to it, then passes deep to the side of the base of the tongue

LINGUAL NERVE :

CHORDA TYMPANI NERVE

Inferior alveolar nerve:

Largest of the posterior division , it passes downwards on the medial side of the lateral pterygoid muscle and the medial side of the mandibular ramus, it then enters the mandibular foramen it descends in the inferior alveolar canal and is distributed throughout the body of the mandible,

it gives off branches to the mandibular teeth as apical branches that enter the apical foramina of the lower teeth to supply the dental pulps and some fibers are distributed to supply the periodontal membrane of various lower teeth

Inferior alveolar nerve

Inferior alveolar nerve

Terminal branches :

As it reaches the mental foramen ,it divides into 2 branches 1) mental nerve : leaves the body through the mental foramen to transmit sensory fibers to the skin of the chin and lower lip and the mucous membrane lining the lower lip

2)incisive branch: continues anteriorly within the body of the mandible to form the incisive plexus that supplies the cuspid tooth and the incisor Before the inferior alveolar nerve enters the foramen , it gives off the mylohyoid nerve which continues forward and downwards in the mylohyoid groove to give motor supply to the mylohyoid muscle

MENTAL NERVE :

Nerve to mylohyoid muscle

Autonomic Ganglia Associated With The Mandibular Nerve

A. Submandibular /Sub maxillary ganglion

Its a small ovoid body that suspends from lingual nerve above the Submandibular gland . Pre ganglionic fibers come from sup.Salivatory.nucleus and pass via chorda tympani and lingual nerve to the ganglion . Post ganglionic fibers are secreto-motor to the Submandibular and sublingual gland. The ganglion also receives post ganglionic sympathetic fibers from the plexus around the external maxillary artery.

SUBMANDIBULAR GANGLION

b) OTIC GANGLIONIts a flattened ovoid body located on the medial side of undivided mandibular division of trigeminal nerve. Its below the foramen ovale and in front of middle meningeal artery. Has two roots 1.Parasympathetic root originating in inf.salivatory.nucleus,passing via gloss pharyngeal nerve to tympanic nerve, plexus then via lesser petrosal nerve to the otic ganglion. Post ganglionic fibers (secretomotor)pass via auriculo -temporal nerve to the parotid gland .

OTIC GANGLION

Clinical anatomy1) Due to involvement of sensory distribution of trigeminal nerve-HEADACHE-common symptom in involvement -of nose (common cold) -sinusitis -infections of teeth & gums -glaucoma

2) Due to paralysis of masseter & temporalis muscle laxity & atrophy difficulty in closing, opening & clenching the mouth

3)

4)

Paralysis of the pterygoid muscle chin of one side is pushed to the paralysed side by muscle of opposite side. Loss of sensation in ophthalmic division. (nasocilliary nerve)loss of blinking (corneal reflex)

Formation of ulcers on the cornea

Blindness

5) Reffered pain

Pain in different teeth referred to different parts of the face

6)

Mandibular nerve block used to anaesthetize the lower jaw (for extraction of teeth) Lingual nerve lies close to medial side of 3rd molar can be injured in careless extraction In cases of cancer of the tongue have intractable pain lingual nerve can be cut to relieve pain

7)

8)

9)

Trigeminal neuralgia - k/as Tic douloureux , Fothergills disease. - orofacial neuralgia which mainly follows 2nd & 3rd division of 5th cranial n. & almost always exhibit trigger zone - it named tic douloreux coz of spasmodic contraction of facial muscles. C/F-seldom occur before 35 yrs age - > - right side > left - unilateral

Trigger zone vermilion border of lips, alae of nose, cheeks & around eyes Pain searing , stabbing/ lancinating type precipitated by light touch on trigger zone Early stages- pain mild dull aching or burning resembling sharp toothache Each attack persists for few sec- several min.

Rx1. Earliest- peripheral neurectomy at mental / supraorbital/ infraorbital foramen, but temporary relief

2.

Injection of alcohol / phenol / boiling H2O into peripheral n / centrally into gasserion ganglion, but temporary relief ( 6mths- several yrs )

3.

Drugs- phenytoin for management & carbamazepine for diagnostic purpose.

4. Microsurgical decompression of trigeminal root by inflatable balloon newest procedure

10) HERPES ZOSTER-k/as Shingles , Zona-acute infectious viral dsz characterized by inflammation of dorsal root / or extramedullary cranial n. ganglia. -nerves 5th nerve (mostly ophthalmic)

C/F-unilateral vesicles appear in clusters on face along course of affected sensory n. Healing occurs in 2-3 weeks. Oral manifestations painful vesicles buccal mucosa, tongue, uvula , pharynx

a. b.

Diagnosis Viral isolation tissue culture Fluorescent antibody staining technique Rx Antiviral drugs- acyclovir,valacyclovir etc

11) Trigeminal Neuritis 12) Freys syndrome 13) Sphenopalatine neuralgia 14) Paratrigeminal syndrome 15) Totters syndrome 16) Neuroparaxia 17) Congenital cutaneous nevi 18) Pressure on nerve or injury to nerve during implant placement and sinus grafting procedure.

CONCLUSIONThe right and left Trigeminal nerve provides majority of sensory innervation from teeth, bone & soft tissues of oral cavity . Therefore an understanding of management of pain in dentistry requires through knowledge of 5th cranial nerve