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TRIGEMINAL NERVE

TRIGEMINAL NERVE . &. REFERENCE POINTS FOR ANESTHESIA. Kaan Yücel M.D., Ph .D. 23. November .2011 Wednesday. http://yeditepedentistryanatomy.wordpress.com. TRIGEMINAL NERVE. The largest of all the cranial nerves Motor & sensory roots

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TRIGEMINAL NERVE

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  1. TRIGEMINAL NERVE & REFERENCE POINTS FOR ANESTHESIA Kaan Yücel M.D., Ph.D. • 23.November.2011 Wednesday http://yeditepedentistryanatomy.wordpress.com

  2. TRIGEMINAL NERVE The largest of all the cranial nerves Motor & sensory roots Motor root originating in the motor nucleus within the pons and medulla oblongata, and sensory root in the anterior aspect of the pons.

  3. Sensory nerve for the face and the motor nerve for the muscles of mastication and several small muscles. Thesensoryportion of thetrigeminalsuppliestouch-pain-temperaturetotheface.

  4. Thetrigeminalnerve [V] dividesintothreemajordivisionsbeforeleavingthemiddlecranial fossa. : Ophthalmicnerve[V1] Maxillarynerve[V2] Mandibularnerve [V3] Thesenervesarenamedaccordingtotheirmainareas of termination: theeye, maxilla, andmandible, respectively.

  5. Each of thesedivisionspassesout of thecranialcavitytoinnervate a part of theface, somost of the skin coveringtheface is innervatedbybranches of thetrigeminalnerve [V]. Theexception is a smallareacoveringtheangleandlowerborder of theramus of mandibleandparts of theear, whichareinnervatedbythetrigeminal [V], facial [VII], vagus [X], andcervicalnerves. 1- Ophthalmic 2- Maxillary3- Mandibular4- Great auricular C35- Lesser occipital C2 6-Other branches of the cervical plexus . 

  6. TrigeminalGanglion (Semilunarganglion) Crescent-shaped Situiatedwithin an invaginatedpocket of dura in themiddlecranial fossa. Liesneartheapex of thepetroustemporal bone. Representsthefirstcellstationforallsensoryfibres of thetrigeminalnerveexceptthosesubservingproprioception.

  7. OPHTHALMIC NERVE (CN V1) Superiordivision of thetrigeminalnerve Smallest of thethreedivisions of CN V. Exitstheskullthroughthesuperiororbitalfissureandenterstheorbit.

  8. MAXILLARY NERVE (CN V2) Intermediatedivision of thetrigeminalnerve Arises as a whollysensorynerve. Suppliesupperlip, lateralandposteriorportions of nose, uppercheek, anteriortemple, mucosa of nose, upperjaw, upperteeth, roof of mouth, and dura of part of themiddlecranial fossa.

  9. Passesanteriorlyfromthetrigeminalganglionandleavesthecraniumthroughtheforamen rotundum in thebase of thegreaterwing of thesphenoid. MAXILLARY NERVE (CN V2)

  10. MAndIBULAR NERVE (CN V3) Inferiorandlargestdivision of thetrigeminalnerve. Exitstheskullthroughtheforamen ovale. Supplieslowerlip, chin, posteriorcheek, temple, externalear, mucosa of lowerpart of mouth, anteriortwo-thirds of thetongue, andportions of the dura of anteriorandmiddlecranialfossae.

  11. MAndIBULAR NERVE (CN V3) Theonlydivision of CN V thatcarries motor fibers. Themajorcutaneousbranches of CN V3 Auriculotemporal, buccal, andmentalnerves.

  12. THE ANATOMY OF TRIGEMINAL ANESTHESIA • The local infiltration technique anesthetizes the terminal nerve endings of the dental plexus. • The field blockanesthetizes the terminal nerve branches in the area of treatment. • A nerve block anesthetizes the main branch of a specific nerve allowing treatment to be performed in the region innervated by the nerve.

  13. The most commonly anesthetized nerves in dentistry are branches or nerve trunks associated with the maxillary and mandibular divisions of the trigeminal nerve. • Dentists are aware of the relative ease of successfully performing pain-free intraoperative procedures in maxillary teeth. The maxilla’s relatively porous alveolar bone allows for the use of straightforward local anesthetic techniques of paraperiosteal field blocks or infiltrations. • The mandible is different. The outer layer of cortical bone is thick and nonporous and thus normally requires the use of a nerve block at a site away from the teeth being treated.

  14. ANESTHESIA OF THE MAXILLARY TEETH From an anatomicalperspective, maxillaryinjectionsgenerallyarebelievedto be not onlymorepredictablethanmandibularinjections, but alsomorebenignandassociatedwithfewercomplications. However, this is not necessarilytrue, particularlyforblockinjections.

  15. Techniques of Maxillary Regional Anesthesia • The techniques most commonly employed in maxillary anesthesia include • Supraperiosteal (local) infiltration • Periodontal ligament (intraligamentary) injection • Posterior superior alveolar nerve block • Middle superior alveolar nerve block • Anterior superior alveolar nerve block • Greater palatine nerve block • Nasopalatine nerve block • Local infiltration of the palate • Intrapulpal injection • Of less clinical application are the maxillary nerve block and intraseptal injection.

  16. ANESTHESIA OF THE MAXILLARY TEETH Maxillarynerveblock (V2 block) can be usedtoanesthetizemaxillaryteeth, alveolus, hard andsofttissue on thepalate, gingiva, and skin of thelowereyelid, lateralaspect of nose, cheek, andupperlip skin andmucosa on sideblocked.

  17. POSTERIOR SUPERIOR ALVEOLAR (PSA) • NERVE BLOCK The PSA nerveblock is usedtoanesthetizethepulpaltissue, correspondingalveolar bone, andbuccalgingivaltissuetothemaxillary 1st, 2nd, and 3rd molars.

  18. POSTERIOR SUPERIOR ALVEOLAR (PSA) • NERVE BLOCK Thearea of insertion is theheight of mucobuccalfoldbetween 1st and 2nd ndmolar.

  19. MIDDLE SUPERIOR ALVEOLAR (MSA) NERVE BLOCK • Usefulfor procedures where the maxillary premolar teeth or the mesiobuccal root of the 1st molar require anesthesia. • Although not always present, it is useful if the PSA or ASA nerve blocks or supraperiosteal infiltration fails to achieve adequate anesthesia. Present in about 28% of the population. The height of the mucobuccal fold above the maxillary 2nd premolar is the injection site.

  20. ANTERIOR SUPERIOR ALVEOLAR (ASA) • NERVE BLOCK The ASA nerveblock is usedtoanesthetizethemaxillary canine, lateralincisor, centralincisor, alveolus, andbuccalgingiva. The area of insertion is height of mucobuccal fold in area of lateral incisor and canine. The mucobuccal fold over the maxillary first premolar is another suggested site for injection.

  21. ANTERIOR SUPERIOR ALVEOLAR (ASA) • NERVE BLOCK Inordertoanestheticallyblocktheanteriorandmiddlesuperioralveolarnerves, it is essentialtolocalizetheinfraorbitalforamenwhich, whenreachedwith a needle, permitsthediffusion of theanestheticsolutionthroughtheinfraorbitalcanal.

  22. INFRAORBITAL(ASA) • NERVE BLOCK The area of insertion is height of mucobuccal fold in area of lateral incisor and canine.

  23. ANTERIOR SUPERIOR ALVEOLAR (ASA) • NERVE BLOCK Theanatomicallocation of thisforamen has beenstudiedbynumerousauthors. MartaniandStefani (1965), studyingtheposition of thisanatomicaccidentwithinstatistical, morphologicalandtopographicalaspects, provide an extensivebibliographicalreview of thistopic.

  24. ANTERIOR SUPERIOR ALVEOLAR (ASA) • NERVE BLOCK • Inadults, theinfraorbitalforamenliessignificantlybelowtheinfraorbitalrim (8 to 10 millimeters), a safedistancefromthecavity of theorbit.

  25. ANTERIOR SUPERIOR ALVEOLAR (ASA) • NERVE BLOCK Insert the needle over the first premolar toward the infraorbital foramen. The needle should be held parallel with the long axis of the tooth. Advance the needle toward the upper rim of the infraorbital foramen beneath the tip of the index.

  26. ANTERIOR SUPERIOR ALVEOLAR (ASA) • NERVE BLOCK Tolocatetheinfraorbitalforamen, thedentist can palpate a smalldepression in theinfraorbitalrim—theinfraorbitalnotch—createdbythezygomaticomaxillarysuture. Placeyour in thisnotch, anddirecttheneedlethroughthevestibularmucosaoverthefirstpremolartoothandtowardthefinger.

  27. PALATAL INNERVATION Themucosa of the hard palateandthepalatalgingivaaresuppliedbythenasopalatineandgreaterpalatinenerves. Theboundarybetweentheareasinnervatedbythetwonervescorrespondsroughlyto a linedrawnbetweenthemaxillarycanines; however, thetwoareasare not sosharplydelineated as suchanimaginarylinemightsuggest.

  28. NASOPALATINE NERVE BLOCK Thenasopalatinenerveblock can be usedtoanesthetizethesoftand hard tissue of themaxillaryanteriorpalatefrom canine to canine. The area of insertion is immediately lateral to the incisive papilla into incisive foramen to completely anesthetize the central incisors

  29. GREATER PALATINE NERVE BLOCK Inthegreaterpalatinecanaltechnique, thearea of insertion is greaterpalatinecanal. Thetargetarea is themaxillarynerve in thepterygopalatine fossa. The dentist performs a greater palatine block and waits 3 3-5 mins. Then h/she inserts needle in previous area and walks into greater palatine foramen.

  30. GREATER PALATINE NERVE BLOCK Theforamen has beenshowntolie 1.9 mm in front of theposteriorborder of the hard palateand 15 mm fromthepalatalmidline. Thesemeasurementsareusefulformoreeasilylocatingthegreaterpalatineforamenandenhancingtheanestheticinjectiontechnique in theposteriorpalate.

  31. GREATER PALATINE NERVE BLOCK The greater palatine foramen can be located by on the palatal tissue approximately one centimeter medial to the junction of the 2nd and 3rd molar. While this is the usual position for the foramen, it may be located slightly anterior or posterior to this location.

  32. ANESTHESIA OF THE MANDIBULAR TEETH Thebuccalcorticalplate of themandiblemostoften is sufficiently dense toprecludeeffectiveinfiltrationanesthesia in itsvicinity. Theinfiltrationtechniques do not work in theadultmandibleduetothe dense cortical bone. Therefore, thedentistmustrely on blockanesthesiaforeffectivelyanesthetizingmandibularteeth.

  33. ANESTHESIA OF THE MANDIBULAR TEETH Nerveblocksareutilizedtoanesthetizetheinferioralveolar, lingual, andbuccalnerves. Itprovidesanesthesiatothepulpal, alveolar, lingualandbuccalgingivaltissue, and skin of lowerlipandmedialaspect of chin on sideinjected.

  34. INFERIOR ALVEOLAR NERVE BLOCK Themostcommonapproachtoinferioralveolaranesthesia is thetraditionalHalsteadmethod. • Inferioralveolarnerve is approached in thepterygomandibularspace, calledtheinfratemporal fossa, via an intraoralroutelocatedjustbeforethenerveentersthemandibularforamen.

  35. INFERIOR ALVEOLAR NERVE BLOCK Thearea of insertion is themucousmembrane on themedialborder of themandibularramus at theintersection of a horizontalline (height of injection) andverticalline (anteroposteriorplane). Injection in proper area of ramus to effect alveolar nerve block Identifyingmandibularramus

  36. INFERIOR ALVEOLAR NERVE BLOCK As thetarget site forthedeposition of anestheticsolution in theconventionalinferioralveolarblockinjection, themandibularforamenis an essentialstructuretoaccuratelylocate. Thetechniqueinvolvesblockingtheinferioralveolarnervepriortoentryintothemandibularlingula on themedialaspect of themandibularramus.

  37. INFERIOR ALVEOLAR NERVE BLOCK Duringadministration of anesthetictotheinferioralveolarnerve, theclinicianmust be aware of theproximalextremity of themaxillaryartery, as well as thecourse of theinferioralveolarartery.

  38. INFERIOR ALVEOLAR NERVE BLOCK

  39. Traditionally, theinferioralveolarnerveblock (IANB), alsoknown as the “standardmandibularnerveblock” orthe “Halstedblock,” has a success rate of only 80 to 85 percent, withreports of evenlowerrates. Investigatorshavedescribedothertechniques as alternativestothetraditionalapproach, of whichtheGow-Gates mandibularnerveblockandAkinosi-Vaziraniclosed-mouthmandibularnerveblocktechniqueshaveprovento be reliable. Dentistswhoknowhowtoperformallthreetechniquesincreasetheirprobability of providingsuccessfulmandibularanesthesia in anypatient.

  40. Theprimarygoal of each of thethreemandibularnerveblocksis anesthesia of theinferioralveolarnerve, whichinnervatesthepulps of themandibularteeth on thesameside of themouth, as well as thebuccalperiodontiumanteriortothementalforamen. Foreach of thethreetechniques, thisgoal is accomplishedbydepositinganestheticwithinthepterygomandibularspace.

  41. GOW-GATES • MANDIBULAR NERVE BLOCK DescribedbyGow-Gates in 1973. Theobjective of thetechnique Toplacetheneedle tip andadministerthelocalanesthetic at theneck of thecondyle. Thisposition is in proximitytothemandibularbranch of thetrigeminalnerveafter it exitstheforamen ovale.

  42. AKINOSI-VAZIRANI CLOSED-MOUTH MANDIBULAR NERVE BLOCK Described as an alternativetothe IANB in 1977. Whatmakesthistechniqueunique is thatthepatient’smouth is closed. Theobjective is toplacetheneedle tip betweentheramusandthemedialpterygoidmuscle.

  43. LINGUAL NERVE BLOCK Branches of thelingualnervesupplythelingualgingivaandadjacentmucosa of themandible. Thelingualnervecoursesthroughtheinfratemporal fossa anteriortotheinferioralveolarnerve.

  44. BUCCAL NERVE BLOCK Traditionally, thebuccalnerveblockinjection is deliveredtotheanteriorramus of themandible at thelevel of themandibularmolarocclusalplane in thevicinity of theretromolar fossa.

  45. MENTAL NERVE BLOCK Thearea of injectionmucobuccalfold at oranteriortothementalforamen. Thisliesbetweenthemandibularpremolars. • Theposition of thisforamenvariesgreatly, making it difficulttopredictablylocatethisnerveusingintraorallandmarks in a patientwith an intactdentition. Penetrate the mucous membrane at the injection site, at the canine or first premolar, directing the syringe backward and downward transversally toward the mental foramen. Advance the needle until the foramen is reached.

  46. MENTAL NERVE BLOCK

  47. LEGAL COMPLAINTS Mostlocalanaesthesia 'failures' occurwith IAN blocks. Injuriestoinferioralveolarandlingualnervesarecausedbylocalanalgesiablockinjectionsandhave an estimatedinjuryincidence of between 1:26,762 to 1/800,000. Thenervethat is usuallydamagedduringinferioralveolarnerveblockinjections is thelingualnerve. whichaccountsfor 70% of nerveinjuries.

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