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

2. TRIGEMINAL
NERVE
(tri-three; gemini-twins)
-- Hardik Vora
Guided by-
Dr. Manjunath

3. Largest cranial nerve
Mixed -- Small motor root
Large sensory root
Nerve of the first pharyngeal arch

4.  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

5. Attached to lateral part of pons
Sensory root (portio major)
Motor root (portio minor)

7. 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

11. 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

14. 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.

15. Location – midpons
Forms dorsal trigeminothalamic tract
Ascending fibers terminate in this nucleus
Convey light touch, tactile discrimination,
sense of position and passive movements

16. 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

17. Largest nucleus
Extends caudally from main nucleus to level
C3 of spinal cord
Forms ventral trigeminothalamic tract
Conveys pain and temperature

18. extends to the
pontomedullary
junction inferiorly
pontomedullary
junction to obex
Obex(medulla) to C3
level of spinal cord
Tactile sense Pain and temperature

28. 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

29. Ophthalmic division

30. Nervous
tentori
Supratrochlear
Supraorbital

31. Long
ciliary n.Short
ciliary
nerves
Infratrochlear

33. 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

36. Sphenopalatine
ganglion

38. 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

51. In 1988, Dellon & Mackinnon – Sixth
degree injury
Nerve injuries exhibit features of different
degrees of injury

52. 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

53. Implant placement
Hydroxypatite ridge augmentation
Endodontic surgeries
Tumour resection
Salivary gland and duct surgery
Vestibuloplasty
Biopsy procedures

54. • Inferior alveolar nerve injury – 0.41-7.5%
• Lingual nerve injury – 0.06-11.5%

56. Risk factors for nerve injury

57. Local anesthetic toxicity
Formation of epineural hematoma
Needle-barb mechanism of injury
Chemical injury

58. Sagittal split osteotomy
Mandibular advancement procedure
osteotomies.
Intraoral vertical ramus osteotomy (IVRO)
Genioplasty procedures

60. 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

63.  Overinstrumentation
 Chemical injury
 Direct trauma from apicoecotomy

64. 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

65.  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

66. 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

67. 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

68. 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

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