Trigeminal Nerve Anatomy

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THE TRIGEMINAL NERVE

Department of Oral & Maxillofacial SurgeryNARSINHBHAI PATEL DENTAL COLLEGE AND HOSPITAL VISNAGAR

Guided By :Dr. Arvind Agarwal , HOD and ProfessorDr.Anil Mannagutti , ProfessorDr.Shreedevi BhoiPresented by: Dr. Harsh Patel1st year PG

11-Oct-13Oral And Maxillofacial Surgery1

111-10-2013Oral And Maxillofacial Surgery

Contents:IntroductionTrigeminal NucleiFunctional ComponentsCourse & DistributionTrigeminal GanglionDivisions of Trigeminal NerveClinical Examination of V NerveApplied AnatomySummaryReferences


INTRODUCTIONThe largest cranial nerveIt is mixed nerve ( sensory and motor )Sensory to Skin of face -Mucosa of cranial viscera -Except base of tongue and pharynxMotor to Muscles of Mastication -Tensor ville palatini,Tensor tympany -Anterior belly of digastric -Mylohyoid 11-Oct-13Oral And Maxillofacial Surgery3

NUCLEI11-Oct-13Oral And Maxillofacial Surgery4

TRIGEMINAL NUCLEIAcranial nerve nucleusis a collection ofneurons(gray matter) in thebrain stemthat is associated with one or more cranial nerves.Axonscarrying information to and from the cranial nerves form asynapsefirst at thesenuclei. Lesions occurring at these nuclei can lead to effects resembling those seen by the severing of nerve(s) they are associated with.


SENSORY NUCLEI :

1.Mesencephalic nucleusCell body of Pseudounipolar neuron Relay proprioception from muscles of mastication, Extra ocular Muscles, Facial muscles. Situated in Midbrain just latetral to Aqueduct.


2.Principal sensory nucleus-Lies in Pons lateral to Motor nucleus Relays touch sensation


3.Spinal nucleus-

Extends from caudal end of principal sensory Nucles in pons to 2nd or 3rd spinal segment It relys Pain and Temperature


MOTOR NUCLEUS :Innervates muscles of mastication and tensor tympani and tensor palatini Derived from first branchial arch. Located in pons medial to principle sensory nucleus.11-Oct-13Oral And Maxillofacial Surgery9



FUNCTIONAL COMPONENTS

Sensory Root Motor Root11-Oct-13Oral And Maxillofacial Surgery12

SENSORY ROOTGENERAL SOMATIC AFFERENTS- Face, Scalp, Teeth, Gingiva, Oral, Nasal, Cavities, Para nasal sinus, Conjunctiva and Cornea.

Pain, temp, light touch touch, pressure proprioception Trigeminal gang. Bypasses trigem gang. sensory root.

11-Oct-13Oral And Maxillofacial Surgery13Spinal nuc. Principal sen nuc. MesencephalicCNS

MOTOR NUCLEUS

MOTOR ROOT

MANDIBULAR NERVE

Muscles of mastication Tensor tympani Masseter Tensor palatini Lateral & Medial Pterygoids Temporalis CNS11-Oct-13Oral And Maxillofacial Surgery14MOTOR ROOT


COURSE & DISTRIBUTIONBoth motor and sensory root are attached ventrally to junction of pons and middle cerebellar peduncle with motor root lying ventromedially to the sensory root.

Pass anteriorly in middle cranial fossa to lie below tentorium cerebelli in cavum trigeminale, here motor root lies inferior to sensory root.11-Oct-13Oral And Maxillofacial Surgery16

Sensory root connected to postromedial concave border of the trigeminal ganglion.

Convex antrolatateral margin of the ganglion gives attachment to the 3 div. Of the trigeminal nerve.





Motor root turns further inferior with sensory component of V3 to emerge out of foramen Ovale as Mandibular nerve. Ophthalmic and Maxillary division emerges through Superior orbital fissure and foramen Rotundum respectively.



GANGLION11-Oct-13Oral And Maxillofacial Surgery23

THE TRIGEMINAL GANGLIONSEMILUNAR OR GASSERIAN GANGLION.Cresentric in shape with convexity anterolaterally.Contains cell bodies of pseudounipolar neurons.LOCATION: lies in a bony fossa at apex of the petrous temporal bone on floor of middle cranial fossa, just lateral to posterior part of lateral wall of the cavernous sinus.


COVERINGS: covered by dural pouch = MECKLES CAVE or CAVUM TRIGEMINALE. cave lined by pia and arachnoid thus the ganglion is bathed in CSF.

ARTERIAL SUPPLY: Ganglionic branches of Internal Carotid Artery, middle meningeal artery and accessory meningeal artery. 11-Oct-13Oral And Maxillofacial Surgery25


RELATIONS: SUPERIORLY: *superior petrosal sinus *free margin of tentorium cerebelliINFERIORLY: *motor root *greater petrosal nerve *petrous apex *foramen lacerumMEDIALLY: *posterior part of lateral wall of cavernous sinus *Internal Carotid Artery with its sympathetic plexusLATERALLY: *uncus of temporal lobe *middle meningeal artery and vein *nervous spinosum 11-Oct-13Oral And Maxillofacial Surgery27


DIVISIONS OF TRIGEMINAL NERVE

1. Ophthalmic nerve 2. Maxillary nerve 3. Mandibular nerve11-Oct-13Oral And Maxillofacial Surgery29


OPTHALMIC NERRVE11-Oct-13Oral And Maxillofacial Surgery31

OPHTHALMIC NERVESmallest division. Sensory onlySupplies : eyeballs, conjunctiva, lacrimal gland, mucosa of nose and paranasal sinus, skin of forehead eyelid and nose


Course:

3 branches in ant part of cavernous sinus superior orbital fissure lat wall cavernous sinusorbit lacrimal, nasocilliary, frontalemerges from trigeminal ganglion 11-Oct-13Oral And Maxillofacial Surgery33


LACRIMAL NERVE

Smallest Passes into orbit through lateral compartment of the Superior orbital fissure outside the tendinous ring.Receives communicating branch from Trochlear nerve branch of Opthalmic


Receives branch from Zygomaticotemporal nerve branch of maxillarySensory to lateral conjunctiva, Upper Lid, lacrimal glandPost synaptic parasympathetic fibers from pterigopalatine ganglion to lacrimal gland (parasym secretomotor).



FRONTAL NERVELargest Enters orbit through lateral part of superior orbital fissure outside tendinous ringPasses forward between roof of orbit and Levator Palpebral Superioris Supratrochlear Nerve Divides midway into : Supraorbital Nerve 11-Oct-13Oral And Maxillofacial Surgery38


SUPRATROCHLEAR NSUPRAORBITAL NSmaller nerveMedial branchReceives communication branches from infratrochlear nerveCurves around superomedial margin of orbit

Larger nerve lateral branchPasses through supraorbital notch Divides in medial and lateral branches.


supplies: median conjunctiva, Upper Lid and lower part of foreheadLies between frontalis and corrugator supercilliary muscles

Lies beneath frontalis muscleSupplies: conjunctiva, scalp upto vertex , mucous membrane of frontal sinus


NASOCILLIARY NERVE

Purely SensoryPasses through middle part of superior orbital fissure within the tendenious ring . Runs along medial wall of orbit between Superior Oblique and Medial RectusDivides into Anterior Ethmoidal and External Nasal5 branches in orbit.


1. Short Clliary Nerves: Fibers reaches eyeball and also contains fibers from Cilliary Ganglion2. Long Cilliary Nerves : 2 or 3in no. supply to Iris and Cornea.3. Post Ethmoidal Nerve: passes through posterior ethmoidal foramen to supply the Ethmoid and Sphenoid PNS.4. Infratrochlear Nerve: appears on face above med angle the eye. Supplies to skin of lacrimal sac and caruncle.




l5. Anterior Ethmoidal Nerve: larger terminal branch Course: anterior ethmoidal foramen and canal into anterior cranial fossa on sup surf of cribriform plate

Through slit lat to crista galli into nasal cavity

Med internal nasal branch lat internal nasal branchSupplies ant nasal septum supplies ant part lat nasal cavity emerges as external nasal nerve to skin of ala,vestibule,and tip of nose 11-Oct-13Oral And Maxillofacial Surgery46

MAXILLARY NERVE11-Oct-13Oral And Maxillofacial Surgery47


MAXILLARY NERVESecond division of trigeminal nervePure sensorySupplies derivatives of maxillary process and frontonasal process


Course: 11-Oct-13Oral And Maxillofacial Surgery50Trigeminal ganglion-> Middle cranial fossaLateral wall of cavernous sinusForamen rotundum Pterigopalatine fossaIn groove on posterior surface of maxillaThrough inferior orbital fissure into orbit as INFRA ORBITAL NThrough infraorbital foramen on face

After leaving foramen rotundum it moves anteriorly in the uppermost part of pterygopalatine fossa.As it passes through pterygopalatine fossa it also gives branches to sphnopalatine ganglion, posterior superior alveolar nerve and zygomatic branches.


It then moves laterally and moves in a groove on posterior surface of maxilla.Then enters orbit through infra orbital fissure and moves through infra orbital groove where it is called as Infraorbital nerve and emerges on face from infra orbital foramen.




BRANCHESIN MIDDLE CRANIAL FOSSA:- Meningeal branch:Travels along the middle meningeal artery and provides sensory innervation to cranial dura matter.11-Oct-13Oral And Maxillofacial Surgery55

IN PTERIGOPALATINE FOSSA:1. Ganglionic branches-Arises as 2trunks.Trunks join to form single root within pterygopalatine ganglion.Gives Orital branches,Palatine branches,Pharyngeal branches,Nasal branchesGives postganglionic secretomotor fibers to lacrimal gland via zygomaticotemporal and lacrimal.


2.Orbital branch: Supplies periosteum of orbit3.Nasal branch: Supplies to mucosa of superior and inferior conchae, posterior ethmiodal sinus and posterior portion of nasal septum. It also includes Nasopalatine branch. -It passes across roof of nasal cavity downwards and forwards lying between mucosa and periosteum of nasal septum. -Reaches to floor of nasal cavity n give branch to anterior part of nasal septum and floor of nasal cavity. -Enters Incisive canal and enters oral cavity through insicive foramen -It provides sensation to palatal mucosa of premaxilla region.11-Oct-13Oral And Maxillofacial Surgery57



4. Palatine branch: Arise as greater palatine (anterior) and lesser palatine (middle and posterior) -Greater palatine nerve descends through pterygopalatine canal from the ganglion and emerges from greater palatine foramen of hard palate. -Then moves anteriorly between mucoperiostem and hard palate upto 1st premolar supplying sensory innervation to palatal soft tissue and bone. Then communicates with nasopalatine -Middle palatine and posterior palatine emerges from lesser palatine foramen and supply soft palate and tonsilar region respectively.11-Oct-13Oral And Maxillofacial Surgery60


5. Pharyngeal branch: It leaves the posterior part of pterygopalatine ganglion and passes through the phryngeal canal It is distributed to the mucous mambreane of the nasal part of pharynx, posterior to eustachian tube.11-Oct-13Oral And Maxillofacial Surgery62

POST. SUPERIOR ALVEOLAR NERVE

-It arises from the main trunk of maxillary nerve in the petrygopalatine fossa just before the nerve enters the inferior orbital canal- Usually arises as 2 trunks.- Passes downwards and crosses the pterygoplatine fossa reaching infratemporal surface of maxilla.- 1st trunk continues downwards on posterior surface of maxilla and provide sensory innervation to buccal gingiva in maxillary molar region and adjacent facial mucosal surface


-2nd trunk enters maxila through PSA canal to travel to posterolateral wall of maxillary sinus providing sensory innervation to sinus mucosa. Continuing downwards this also provides sensory innervation to alveoli, PDL, pulp of molar tooth.



Zygomatic nerve :

A. Zygomaticofacial nerve -Appears on face through foramen in the zygomatic bone -Supplies skin on prominence of cheek B. Zygomaticotemporal nerve -Appears in infratemporal region thru foramen in zygomatic bone -Supplies skin of temporal region after peircing temporal fascia 2 cm above zygoma -Gives communicating branch to lacrimal N suppling parasymp. Secretomotor fibres to lacrimal gland. 11-Oct-13Oral And Maxillofacial Surgery66It enters orbit through infra orbital fissure.

IN THE INFRAORBITAL CANAL 1.Middle superior alveolar nerve: runs along lat wall of maxilla Participates in superor dental plexus Supplies premolars. 2. Anterior superior alveolar nerve: Runs in canal in ant wall of maxilla=canalii sinosus #Dental branches # nasal branches

Joins sup dental plexus lat wallof inf meatus to to supply canines opening of max sinus. 11-Oct-13Oral And Maxillofacial Surgery67

3. FACIAL BRANCHES:1.Palpebral nerves-pierces Orbicularis Occuli and supplies skin of lower lid.

2.Nasal branches-supplies skin of lat wall nose and mobile part of septum.

3. Superior labial nerve- forms infraorbital plexus supplies skin and mm of upper lip, cheek and labial glands.11-Oct-13Oral And Maxillofacial Surgery68


MANDIBULAR NERVE11-Oct-13Oral And Maxillofacial Surgery70

MANDIBULAR NERVELargestMixedNerve of 1st branchial arch

Motor root- from motor nucleus in ponssensory root- gasserian ganglion aa small ant. Division

exit through foramen ovale in greater wing of sphenoidfrom trunk which remain 2-3 mm undivided in infratemporal fossatravels between lat. Pterygoid and Otic ganglion laterally and tensor palatine medially anteriorly to med. Meningeal A.large post. division11-Oct-13Oral And Maxillofacial Surgery71


BranchesTrunk (undivided)Nervous SpinosusNerve to medial PterygoidAnterior DivisionMassetric Nerve.Deep temporal Nerve.Nerve to lateral PterygoidBuccal Nerve.Posterior DivisionAuriculo Temporal NerveInferior. Alveolar NerveLingual Nerve.11-Oct-13Oral And Maxillofacial Surgery73

Branches from trunkBefore dividing into anterior and posterior division it gives 2 branches during its 2-3mm path1.Nervous spinosus or Meningeal branch of Mandibular nerveIt reenters cranial cavity through foramen spinosus along with middle meningial arterySupply Dura matter of middle cranial fossa and mastoid air sinus2.Nerve to mededial PterygoidSupplies medial pterygoidThrough Otic ganglion without interruption to Tensor tympaniTensor palatini 11-Oct-13Oral And Maxillofacial Surgery74


Branches from the anterior divisionThe anterior division is significantly smaller than posterior. After dividing from the main trunk. It runs anteriorly and below the lateral pterygoid muscle to over its upper border. After this the nerve is buccal nerve. reach its external surface of muscle by either passing through two heads or winding 1.Nerve to lateral pterygoid: It enters the deep surface of the muscle. It may arise as independent branch or may arise in common with buccal nerve.11-Oct-13Oral And Maxillofacial Surgery76

2.Massetric nerve- Emerges at the upper border of the lateral pterygoid just in front of TMJ. Passes laterally through mandibular notch along with massetric vessels, and enters the deep surface of masseter, also suppliesTMJ3.Buccal nerve-is the only sensory branch of ant div. travels betwn 2 heads of lat pterygoid and emerges in cheek at ant border of masseter. Supplies skin and mucous membrane of cheek.4.Deep temporal nerve-There are anterior and posterior deep temporal nerves. Passes between skull, and enters deep surface of the temporalis. Anterior is often a branch of buccal nerve and the posterior may arise in common with massetric nerve.



Branches Of Posterior Division11-Oct-13Oral And Maxillofacial Surgery79

1.Auriculotemporal nerve- Arises from 2 roots which run backwards and encircle the middle meningeal artery and form single trunk

The trunk passes posterior to lateral pterygoid between neck of mandible and sphenomandibular ligament superior to 1st part of maxillary art.

Lies behind the TMJ close to the parotid

Ascends behind superficial temporal vessels and then in temporal region divides into superficial temporal branches.



Branches Of Auriculotemporal Nerve

Auricular branches- supply tragus, upper part of aurical,roof of external auditory meatus, anterosuperior part of tympanic membrane

Superficial temporal branches-supply skin of templeIt also supply sensory and secretomotor to parotid.Articular branches-supply the TMJ.


2. Inferior alveolar nerve:Is mixed nerveRuns vertically downwards medial to lateral ptrygoid and lateroposterior to lingual nerve. Then moves between the sphenomandibular ligament and medial surface of mandibular ramusEnters mandible through mandibular foramen to run in a bony canal below the teeth


Branches:1.Mylohyoid: Arises just before the nerve enters mandibular foramen.It pierces the sphenomandibular ligament along with mylohyoid muscle and runs in the mylohyoid goove. Supplies to mylohyoid muscle and anterior belly of digastric. It is also sensory to skin on inferior and anterior surface surfaces of mental protuberence. It may provide sensory innervation to mandibular incisors. There is also evidence that mylohyoid supply to mesial root of mandibular frist molar.2.Branches to lower teeth and gums.3.Mental nerve : It exits canal and divides into three branches innervating skin of chin and skin and mucous membrane of the lower lip.4.Incisive nerve : It remains within the canal and form plexus that innervates pulpal tissue of first premolar canine and incisors through dental branches.




3.Lingual nerve: lies anterior to inferior alveolar n between lateral pterygoid and tensor palatini

receives chorda tympani (SVA)

Emerges from inferior border of lateral pterygoid to lie between ramus and medial pterygoid in peterygomandibular space

moves downwards and forwards deep to pterygomandibular raphe between origins of supirior constrictor and mylohyoid

Reach to side of base of tongue 1 cm below and behind 3rd molar just below mucous membrane of lateral lingual sulcus


11-Oct-13Oral And Maxillofacial Surgery88-Then proceeds anteriorly across the muscles of tongue ,looping medially and downwards to submandibular duct to deep surface of submandibular gland where it break in terminal branches

-Sensory to anterior 2/3 of tonge along with special sensation also sensory to floor of mouth and gingiva on lingual side of mandible.




Branches of lingual nerve and its communications:

1.Chorda tympani

2.Communications with submandibular ganglion

3.Hypoglossal nerve11-Oct-13Oral And Maxillofacial Surgery92

Ganglia Associated With The Trigeminal Nerve1.Cilliary Ganglion: connected with nasocilliary nerve by ganglionic branches in orbit, non synapsing sensory for orbit

2.Pterygopalatine Ganglion: connected to maxillary nerve in infratemporal fossa sensory to orbital septum, orbicularis and nasal cavity, max sinus, palate, nasopharynx.

3. Otic Ganglion: betwn trunk of mandibular n and tensor palatini, nerve to med pterygoid passes thru but does not synapse in the ganglion.

4.Submandibular Ganglion: related to lingual n, rests on hypoglossus supplies post gang. Parasym secretomotor fibres to submandibular and sublingual gland.11-Oct-13Oral And Maxillofacial Surgery93

CUTANEOUS DISTRIBUTION OF TRIGEMINAL NERVEEach half of face is supplied by 13 cut N1motor and 12 sensoryOf 12 sensory : 11 are from trigeminal N 1 is c2 greater auricular NBranches of trigeminal N5 from ophthalmic: lacrimal supraorbital supratrocheal infratrochlear external nasal 11-Oct-13Oral And Maxillofacial Surgery94


3 from maxillary N: infra orbital N zygomaticofacial N zygomaticotemporal N3 from mandibular N: buccal N auriculotemporal N mental N

DIVISIONAL SUPPLY:From lat canthus to vertex- ophthalmic NFrom angle of mouth to vertex- mandibular NBetween the two areas-maxillary N


Examination of trigeminal nerve


Examination of trigeminal nerve1- Sensation Function2- Motor Function3- Corneal reflex4- Test jaw jerk


Sensation functionuse sterile sharp item on forehead, cheek, and jawIf any abnormality present we test the thermal sensation and light touch


Corneal reflexa clean piece of cotton wool and ask the patient to look away gently touch the cornea with the cotton wool and the patient will blink.11-Oct-13Oral And Maxillofacial Surgery100

Test jaw jerkDoctor finger on tip of jaw, grip patellar hammer halfway up shaft and tap finger lightly usually nothing happens, or just a slight closure.


APPLIED ANATOMY


1. Trigeminal Neuralgia Tic DouloureuxSudden, usually unilateral severe, brief, stabbing lancinating, recurring pain in the distribution of one or more branches of the 5th Nerve


2. TRIGEMINAL NEUROPATHYsensory loss of face or weakness of the jaw musclescauses- sjogren syndrome herpes zoster, leprosymeningioma,schwanomma11-Oct-13Oral And Maxillofacial Surgery104

4. HERPES ZOSTER OPHTHALMICUS:Recurrent neurocutaneous inf. In opth. Div. of trigeminal dermatome, most freq. affecting nasociliary branchHHV3 / vericella zosterGasserian ganglion

ophthalmic nerve

Supraorbital N.Infraorbital N.Supratrochlear N.Infratrochlear N.Nasal N.11-Oct-13Oral And Maxillofacial Surgery105


5. Cavernous sinus syndromeCavernous sinus syndromeMultiple cranial neuropathiesExophthalmos, ocular motor defects, sensory loss in V1 and / or V2.Pupils may be spared or involved. causes: bacterial thrombophlebitis actinomycosis rhinocerebellar mucormycosis aspergillosis tolosa hunt syndrome neoplasms vascular lesions 11-Oct-13Oral And Maxillofacial Surgery107

6.Gradenigos syndrome Petrous bone osteitis due to otitis mediaCharacterized by I/L trigeminal N palsy (Va, Vb) retro orbital pain I/L sixth N palsy. 11-Oct-13Oral And Maxillofacial Surgery108

ConclusionSince Trigeminal nerve is mixed nerve, suplies mainly head and neck region. Hence as a Oral and Maxillofacial surgeon one should know throughly about itracranial and extracranial course and distribution of Trigeminal nerve,to diagnose the pathologies associated with Trigeminal nerveand for appropriate treatment.11-Oct-13Oral And Maxillofacial Surgery109

Refrences: Greys anatomy Snells anatomy Head and Neck Anatomy-BD Chourasia Textbook of Local Anesthesia-Stenly F Malamed


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Trigeminal Nerve Anatomy