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Trigeminal nerve

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Trigeminal nerve, branches and clinical anatomy,pathways,mixed nerve

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Trigeminal nerve

  1. 1. TRIGEMINAL NERVE (tri-three; gemini-twins) -- Hardik Vora Guided by- Dr. Manjunath
  2. 2. Largest cranial nerve Mixed -- Small motor root Large sensory root Nerve of the first pharyngeal arch
  3. 3.  Exteroceptive from Skin of the face & forehead; Mucous membrane of the nasal cavity; Oral cavity; Nasal sinus; Floor of mouth, teeth; Anterior 2/3 of tongue; Cranial dura Proprioception from  Teeth;  Periodontium;  Hard palate;  TMJ
  4. 4. Attached to lateral part of pons Sensory root (portio major) Motor root (portio minor)
  5. 5. Fibers arise from Semilunar Ganglion Semilunar ganglion – Develops from neural crest – Crescent shaped – Unipolar neurons – Location- Meckel’s cavity; superior to petrous part of temporal bone
  6. 6. Afferent station Afferent fibers accompany fibers of motor root Proprioception from TMJ, periodontal membrane, teeth, hard palate Afferent impulses from stretch receptors in the muscles of mastication
  7. 7. Located at midpontine level Medial to main sensory nucleus Fibres distribute to muscles of mastication, mylohyoid, anterior belly of digastric, tensor tympani, tensor veli palatini.
  8. 8. Location – midpons Forms dorsal trigeminothalamic tract Ascending fibers terminate in this nucleus Convey light touch, tactile discrimination, sense of position and passive movements
  9. 9. True sensory ganglion Contains cells that are structurally and functionally ganglion cells Convey GP input from the muscles innervated by the trigeminal nerve and the extraocular muscles, as well as from the periodontal ligament of the teeth
  10. 10. Largest nucleus Extends caudally from main nucleus to level C3 of spinal cord Forms ventral trigeminothalamic tract Conveys pain and temperature
  11. 11. extends to the pontomedullary junction inferiorly pontomedullary junction to obex Obex(medulla) to C3 level of spinal cord Tactile sense Pain and temperature
  12. 12. Smallest division From anterior medial part of semilunar ganglion  lateral wall of cavernous sinus Sensory fibres from Scalp, skin of forehead, upper eyelid lining frontal sinus, conjunctiva of eyeball, lacrimal gland, skin of the lateral angle of eyeball & lining of ethmoid cell
  13. 13. Ophthalmic division
  14. 14. Nervous tentori Supratrochlear Supraorbital
  15. 15. Long ciliary n.Short ciliary nerves Infratrochlear
  16. 16. Sensory From lower eyelid, side of the nose, upper lip; All maxillary teeth & gingivae, mucous membrane of most of nasal cavity, hard and soft palate; Tonsillar region and region of pharynx
  17. 17. Sphenopalatine ganglion
  18. 18. Sphenopalatine ganglion Parasympathetic ganglion Stellate; lies deep in pterygopalatine fossa Associated with greater petrosal nerve- branch of facial nerve Relays secretomotor impulse from facial nerve Suspended from V2 by 2 roots
  19. 19. In 1988, Dellon & Mackinnon – Sixth degree injury Nerve injuries exhibit features of different degrees of injury
  20. 20. Surgical removal of third molars(Von Arx and Simpson, 1989; Rood, 1992) Osteotomies (Walter and Gregg, 1979; Yoshida et al, 1989) Trauma (De Man and Bax, 1988) Tooth extractions (Strassburg, 1967; Hansen, 1980) Pulpectomy (Holland, 1994) Experimental Trigeminal Nerve Injury G.R. Holland CROBM 1996 7: 237
  21. 21. Implant placement Hydroxypatite ridge augmentation Endodontic surgeries Tumour resection Salivary gland and duct surgery Vestibuloplasty Biopsy procedures
  22. 22. • Inferior alveolar nerve injury – 0.41-7.5% • Lingual nerve injury – 0.06-11.5%
  23. 23. Risk factors for nerve injury
  24. 24. Local anesthetic toxicity Formation of epineural hematoma Needle-barb mechanism of injury Chemical injury
  25. 25. Sagittal split osteotomy Mandibular advancement procedure osteotomies. Intraoral vertical ramus osteotomy (IVRO) Genioplasty procedures
  26. 26. Fracture of mandibular body and ramus LeFort I & II fractures Fracture of condylar segment medially Mandibular angle, body and symphysis fracture Inadvertent placement of screws Pathologic lesions  use of Carnoy’s solution
  27. 27.  Overinstrumentation  Chemical injury  Direct trauma from apicoecotomy
  28. 28. TMJ exposures by preauricular approach Damage is minimized by incision and dissecting in close apposition to cartilagenous portion of external auditory meatus Fracture of neck of condyle
  29. 29.  Trigeminal neuralgia is defined as sudden, usually unilateral, severe, brief, stabbing, lancinating type of pain in the distribution of one or more branches of 5th cranial nerve Specific etiology unknown
  30. 30. Sudden, unilateral, intermittent paroxysmal, sharp, shooting, lancinating, like pain. Pain is elicited by slight touching superficial ‘Trigger points’ Common triggers include touch, talking, eating, drinking, chewing, tooth brushing, etc
  31. 31. Monheim’s Local anesthesia and pain control in dental practice Handbook of Local Anesthesia - Malamed Textbook of medical physiology –Guyton Peterson’s Principles of Oral & Maxillofacial Surgery
  32. 32. Experimental Trigeminal Nerve Injury G.R. Holland CROBM 1996 7: 237 Prevention of iatrogenic Inferior alveolar nerve injuriesin relation to dental procedures. Dent Update 2010; 37:350-363 J Oral Maxillofac Surg 68:2437-2451, 2010 Frequency of Trigeminal Nerve Injuries Following Third Molar Removal J Oral Maxillofac Surg 63:732-735, 2005
  33. 33. 14/09/13 69

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