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Trigeminal nerve and its course

S
Shruti MISHRA

This document provides an overview of the trigeminal nerve (CN V) including its: - Intracranial course and branches originating from the trigeminal ganglion - Three main divisions - ophthalmic, maxillary, and mandibular nerves - Branches of each division and the areas they innervate, such as the face, nasal cavity, and oral cavity - Applied anatomy and clinical significance of parts like the trigeminal ganglion

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Good Morning
TRIGEMINAL NERVE Presented by:- Dr. Shruti Mishra MDS 1st year Dept. of conservative and Endodontics
GUIDED BY:- • Dr. Gopal Tawani (Reader and Guide) • Dr. Manoj Chandak (Professor and HOD) • Dr. Pradnya Nikhade (Professor) • Dr. Ajay Saxena (Professor) • Dr. Anuja Ikhar (Reader) • Dr. Neelam Chandwani (Reader) • Dr. Aditya Patel (Reader)
CONTENTS • Introduction. • Trigeminal Ganglion. • Origin & Attachments of the Trigeminal Nerve • Branches of the Trigeminal Nerve. Course. Branches. Innervations. • Applied Anatomy. • Summary
SPECIFIC LEARNING OBJECTIVES S/N Learning Objectives Domain Level Criteria 1. Intracranial course Cognitive Must know All 2. Trigeminal ganglion Cognitive Must know All 3. Origin and attachments of the trigeminal nerve Cognitive Must know All 4. Branches of the nerve Cognitive Must know All 5. Course and innervations Cognitive Must know All 6. Applied anatomy Cognitive Must know All
INTRODUCTION • The word ‘Trigemina’ meaning ‘Threefold’ gives the V Cranial Nerve its name – The Trigeminal or Trifacial Nerve as it forms 3 divisions:- 1. The Opthalmic(sensory) 2. The Maxillary(sensory) & 3. The Mandibular nerve(Sensory,motor). • It is the largest of all the Cranial Nerves, & of mixed variety having a large sensory root & a small motor root. • As major general sensory nerves of face, it transmits afferent impulses from Touch, Temperature & Pain receptors.
Figure showing inferior view of the brain showing cranial nerves and the organs and tissue they innervate
• It is composed of a small motor root and a considerably larger (tripartite) sensory root. • The motor root supplies the muscles of mastication and other muscles in the region. • The three branches of sensory root supply the skin of the entire face and the mucous membrane of the cranial viscera and oral cavity, except for the pharynx and base of the tongue.
ORIGIN • Cell bodies of sensory neurons of all three divisions are located in the large Trigeminal (or Semilunar or Gasserian or Gasser's) Ganglion. • The mandibular division also contains motor fibers that innervate the muscles of mastication. Gaserrian ganglion
TRIGEMINAL / SEMILUNAR / GASSERIAN GANGLION • In 1765, Anton Balthasar Raymund Hirsch, described the Gasserian ganglion, naming it in honor of his professor “Gasser’ a Professor of Anatomy at the University of Vienna. • It is the sensory ganglion of the Vth cranial nerve. • The ganglion is Flat, Crescentric Or Semilunar in shape, measuring 1 x 2 cms with its convexity directed anterolaterally. • The three divisions of the trigeminal nerve emerge from this convexity.
Situation & Meningeal Relations : • The ganglion lies at a depth of 4.5 – 5 cms from the lateral aspect of head, at the posterior extremity of the Zygomatic arch. • It occupies a special space of dura mater, called the Trigeminal (or Meckel’s) Cave covering the trigeminal impression on the anterior surface of the petrous temporal bone near its apex. Clinical Significance : • After recovery from a primary herpes infection, the virus is not cleared from the body, but rather lies dormant in a non-replicating state within the trigeminal ganglion. Thus, herpes zoster may follow from Chickenpox.
Opthamlmic nerve V1 Maxillary nerve V2 Mandibular nerve V3 Trigeminal ganglion Trigeminal nerve Trigeminal Nerve in the interior of the base of the cranium
Sensory root Mouth of Meckel’s cave Trigeminal ganglion Greater pertrosal nerve Lesser petrosal nerve Mandibular nerve Maxillary nerve Opthalmic nerve Lacrimal nerve Frontal nerve Supraorbital nerve Supratroch lear nerve Trigeminal nerve in the Middle Cranial Fossa
ORIGIN & ATTACHMENT • The Trigeminal nerve is attached to the lateral part of the pons by its 2 roots, motor & sensory to its 4 nuclei : 1. Principle sensory nucleus. 2. Mesencephalic nucleus. 3. Motor nucleus. 4. Spinal nucleus. pons Trigeminal ganglion
SPINAL NUCLEUS • Takes pain and temperature sensations from most of the face area which relay here. • The crossed fibres are called trigeminal lemniscus which go to ventroposterior nucleus of thalamus for another relay, to finally terminate in lower part of postcentral gyrus.
SUPERIOR SENSORY NUCLEUS • Fibres carrying touch and pressure relay in this nucleus. • Remaining path is same as that of the spinal nucleus.
MESENCEPHALIC NUCLEUS • This nucleus extends from pons till the midbrain. • Receives proprioceptive impulses from muscles of mastication, temporomandibular joint and teeth.
Trigeminal nerve and its course
Pons Hypoglossal nerve Sensory root Motor root Vagus nerve Superficial origin of trigeminal nerve
SENSORY COMPONENTS OF V NERVE • Sensations of pain, temperature, touch and pressure from skin of face, mucous membrane of nose, most of the tongue, paranasal air sinuses travel along axons. • Their cell bodies lie in the V ganglion. • This ganglion is similar to the spinal ganglia of other nerves. • It lies at the apex of petrous temporal bone in a dural cave, the Meckel’s cave. • Peripheral processes form the three nerves.
Sensory Root : • The large sensory root (portio major) arise from the Semilunar (Gasserian) ganglion & enters the brainstem via the side of the Pons. • The ganglion with its unipolar neurons forms Central & Peripheral processes. • The peripheral branches form the opthalmic, maxillary & mandibular divisions of the nerve while the central branches are the sensory roots of the trigeminal nerve V1 V2 V3
• The central processes of V ganglion form sensory root. • Some fibres ascend and other descend. • Ascending fibres end in superior sensory nucleus. • Descending fibres end in the spinal nucleus of V nerve.
• Pain and temperature reach spinal nucleus. • Touch and pressure sensations go to superior sensory nucleus. • Opthalmic nerve fibres end in the inferior part, maxillary nerve fibres end in the middle part and mandibular nerve fibres terminate in the upper part of the spinal nucleus.
MOTOR COMPONENT • The motor nucleus receives impulses from the right and left cerebral hemispheres, red nucleus and mesencephalic nucleus. • Fibres of motor root supply four muscles of mastication and four other muscles. • It supplies the following muscles : - Muscles of mastication:- 1. Mylohyoid. 2. Ant belly of the diagastric. 3. Tensor tympani. 4. Tensor veli palatini
• The small motor root (portio minor) arises separately from the sensory root, originating in the motor nucleus located in the upper pons and medulla oblongata. Its fibers, forming a small nerve root travels anteriorly along with, but entirely separate from, the larger sensory root to the region of trigeminal ganglion. Here the nerve passes latero-inferior direction under the ganglion towards the foramen ovale, through which it leaves the MIDDLE CRANIAL FOSSA along the mandibular nerve. Just after leaving the skull, the motor root unites with the sensory root of the mandibular division to form a single trunk.
BRANCHES OF THE TRIGEMINAL NERVE • The Trigeminal Nerve forms three divisions : 1) The Opthalmic 2) The Maxillary & 3) The Mandibular Nerves. • All of the three are chiefly sensory in nature but the mandibular division also contains motor fibres that innervate the muscles of mastication.
The general pathway of the trigeminal nerve and its motor and sensory roots and three divisions
Various branches of trigeminal nerve
OPTHALMIC NERVE (V1) • Ist branch of trigeminal nerve. • Sensory in nature. • Smallest branch(2.5cms long) SUPPLIES :- 1.Eyeball 2.Conjuctiva 3.Lacrimal Gland 4.Parts of the mucous membrane of the nose and Paranasal Sinuses 5.Skin of the forehead, eyelid and nose. Just before the ophthalmic nerve passes through the superior orbital fissure it divides into its three main branches: a. Frontal b. Lacrimal and c. Naso-cilliary nerves
COURSE • It courses anteriorly in the lateral wall of the cavernous sinus to the medial part of the superior orbital fissure through which it enters the orbit. • It also gives off communication branches to the Oculomotor, Trochlear and Abducent cranial nerves. As the ophthalmic division passes forward from the cavernous sinus, it divides into three branch’s: Lacrimal, Frontal and Nasociliary Nerves.
Trigeminal nerve and its course
• The internal branch, the nasociliary nerve , follows the medial border of the orbital roof, releases branches to the nasal cavity, and ends on the skin at the root of the nose. • The intermediate branch, the frontal nerve , courses straight anteriorly to reach the skin of the forehead. • Finally the external branch, the lacrimal nerve, runs anteriorly and laterally along the border of roof the orbit toward the lacrimal gland and to the skin at the outer corner of the eye.
• Branches : a) Lacrimal nerve b) Frontal nerve • Supraorbital • Supratrochlear c) Nasocilliary nerve 1) Branches in the Orbit - Long root of ciliary ganglion - Long ciliary nerve - Posterior ethmoidal - Anterior ethmoidal -Internal nasal branches -External nasal branches
2) Branches arising in the nasal cavity 3) Terminal branches of the opthalmic division on the face.
I) LACRIMAL NERVE • Smallest of the three branches. • It passes into the orbit at the lateral angle of the superior orbital fissure & then courses in an anterolateral direction to reach the lacrimal gland. Innervation : a) Skin of the upper eyelid and lateral part of the eyebrow region b) Conjunctiva of the lateral part of the upper eyelid.
II) FRONTAL NERVE • The largest of the three branches, & appears to be a direct continuation of the ophthalmic division. It enters the orbit by way of the superior orbital fissure. At about the middle of the orbit, the frontal nerve divides into two branches: 1) Supraorbital nerve : • Larger branch of the frontal nerve. • It passes forward and leaves the orbit through the supraorbital foramen Innervation :- a) Medial part of the upper eyelid & the lower medial part of the forehead. b) Conjunctiva of the upper eyelid.
2) Supratrochlear nerve • The smallest branch of the frontal nerve. • It passes toward the upper medial angle of the orbit. Innervation : a) Skin of the Upper Eyelid and the skin of the forehead and scalp as far back as the vertex of the skull. b) Lining of the frontal sinus.
III ) NASOCILIARY NERVE • It is the third main branch of the ophthalmic division. It enters the orbit through the Superior Orbital Fissure. • Its branches are divided into those arising in the orbit, in the nasal cavity, and on the face. Innervation :- a. Long ciliary branch : -Sensory from the eyeball and ciliary ganglion. b. Infratrochlear nerve : -Upper and lower eyelid and from the side of the nose. -Conjunctiva and the lacrimal sac. c. Ethmoid branches : Sensory from the lining of the frontal & sphenoid sinus and of the anterior & posterior ethmoid cells.
d. Internal branches : Sensory from the anterior portion of the septum and lateral walls of the nasal cavity. e. External nasal branch : Sensory from the tip of the nose. A) Branches in the orbit : 1. Long root of the ciliary ganglion: The long, or sensory, root arises from the nasociliary nerve. It contains sensory fibers, which pass through the ganglion without synapsing and continue on to the eyeball by means of the short ciliary nerves. 2. Long ciliary nerves: There are usually two or three long ciliary nerves branching from the nasociliary nerve. They are distributed to the iris & cornea.
3. Posterior ethmoid nerve : It enters the posterior ethmoid canal to be distributed to the mucous membrane lining the posterior ethmoidal cells and the sphenoid sinus. 4. Anterior ethmoid nerve : It continues anteriorly along the medial wall of the orbit. In the upper part of the nasal cavity, the ethmoid nerve divides into two sets of anterior nasal branches: a) Internal nasal branches : In turn, divide in the upper anterior part of the nasal cavity into two divisions : - Medial or septal branches. - Lateral branches. b) External nasal branches : At the border between the lower edge of the nasal bone and the upper edge of the lateral nasal cartilage, the external nasal branch passes externally.
B. Branches arising in the nasal cavity:- • The branches of the nasociliary nerve that arise in the nasal cavity supply the mucous membrane lining the cavity. C. Terminal branches of the ophthalmic division on the face:- • These branches course below the trochlear nerve to supply sensory fibers to the skin of the medial parts of both eyelids, lacrimal sac, & the lacrimal caruncle. • These fibers supply the skin over the side of the bridge of nose.
Main branches of ophthalmic nerve
MAXILLARY NERVE (V2) • The maxillary nerve is entirely sensory in function. Intracranial course : • It originates at the middle of the semilunar ganglion & continues forward in the lower part of the cavernous sinus. Extracranial course : • It then passes to the Foramen Rotundum, through which it leaves the cranial fossa and enters the Pterygopalatine Fossa. It enters the Inferior Orbital Fissure to pass into the orbital cavity. Here it turns laterally in a groove on the orbital surface of the maxilla, called the infraorbital groove.
BRANCHES
Maxillary nerve (V2) Cranial cavity Pterygopalatine fossa Infraorbital canal Face / Terminal branches Meningeal Pterygopalatine Zygomatic Posterior superior alveolar Middle superior alveolar Anterior superior alveolar Palpebral Nasal Superior labial
Trigeminal nerve and its course
BRANCHES GIVEN IN THE PTERYGO PALATINE FOSSA Pterygopalatine nerve Zygomatic nerve Posterior superior alveolar nerve Orbital Nasal Pharyngeal Palatine Greater palatine Lesser palatine Nasopalatine nerve Zygomaticotemporal Zygomaticofacial
I) Branches given off in the middle cranial fossa : • In the middle cranial fossa a small branch, the middle meningeal nerve, passes with the middle meningeal artery and its branches to supply the dura with sensory fibers. • Innervation : It sends a sensory branch to the dura.
PTERYGOPALATINE NERVE • Enters the ganglion after a course of only 2-3 mm. • No synapse formation with the cells of the ganglion. • The superior posterior nasal branches are given off :- 1. Lateral nasal • Supplies upper and middle conchae. 2. Medial branch (nasopalatine) • Branches of the septal mucosa passes through the incisive canal to reach the oral cavity.
NASOPALATINE NERVE • Exchanges fibers with anterior superior alveolar nerves and consequently may participate in the innervation of central incisor. • In the nasopalatine canal, the rt. And lt. palatine nerves approach each other and enter the oral cavity through the unpaired incisive foramen. • Supply a small anterior area of the palatine mucosa behind the incisor teeth , from one canine to another.
MAIN PART OF THE PTERYGOPALATINE NERVE • Continues below the pterygopalatine ganglion. • Passes through the pterygopalatine fossa and canal. • Palatine nerves • Before reaching the lower oral end of the pterygopalatine canal, palatine nerve divides into one larger and one or two smaller branch. Larger branch smaller branch
Palatine nerves Larger branch (anterior palatine nerve) Enters oral cavity through the major palatine foramen. Splits into numerous branches that spread fan wise • Anterior • Lateral • Medial Smaller branch Middle and posterior palatine nerves emerge through the lesser palatine foramen and supply the tonsil and the soft palate with sensory twigs
INFRAORBITAL NERVE • Intermediate branch. • Passes through the pterygomaxillary fissure. • Reaches infratemporal fossa. • Leaves immediately through the inferior orbital fissure. • Enters the orbit to run in the infraorbital groove. • The groove is roofed to form the infraorbital canal, which leads the nerve to the infraorbital foramen to the superficial structures of face.
BRANCHES OF INFRAORBITAL NERVE • Superior alveolar nerves. • Posterior superior alveolar nerve. • Middle superior alveolar nerve.
SUPERIOR ALVEOLAR NERVES • Supplies upper teeth, their periodontal membrane and gingivae on the outer surface of the jaw. • In the base of the alveolar process the SAN exchange fibers and form a loose plexus – superior dental plexus. • Two terminal sets of branches:- 1. Dental nerves:- innervates the roots of the superior teeth by entering the apical foramen and branches in the dental pulp. 2. Interdental/ inter radicular nerves:- supplies b/w two adjacent teeth, supplies PDL. They end in the PDL at the furcation of roots.
• Terminal branches :- • They spread fanwise:- 1) Palpebral branches :- turns upward into the eyelid. 2) Nose :- supply the lateral slope of the nose and nasal wing. 3) Upper lip :- 3 or 4 superior labial branches enter the lip between its muscles and mucous membrane.
ZYGOMATIC NERVE • Division occurs either before or while the infraorbital nerve passes through the inferior orbital fissure. • In the orbit, it follows the lateral edge of the orbital floor anteriorly and laterally. • Sends upward branch to the lacrimal nerve. • Enters the zygomatic foramen and reaches the zygomatic bone. zygomatico- zygomaticotemporal facial
Trigeminal nerve and its course
MANDIBULAR NERVE (V3) • This is the largest of the three divisions of the trigeminal nerve. • It has both sensory and motor fibres.(Mixed nerve) • It is the nerve of first branchial arch and supplies all structures derived from the first branchial arch. • Otic and submandibular ganglia are associated with this nerve.
COURSE AND RELATIONS • Mandibular nerve begins in the middle cranial fossa through a large sensory root and a small motor root. • The sensory root arises from the lateral part of the trigeminal ganglion, and leaves the cranial cavity through the foramen ovale. • The motor root lies deep to the trigeminal ganglion and to the sensory root. • It also passes through the foramen ovale to join the sensory root just below the foramen thus forming the main trunk.
• The main trunk lies in the infratemporal fossa, on the tensor veli palatine, deep to the lateral pterygoid. • After a short course, the main trunk divides into a small anterior trunk and a large posterior trunk.
Trigeminal nerve and its course
BRANCHES From the main trunk:- a) Meningeal branch b) Nerve to medial pterygoid From the anterior trunk. a) A sensory branch, the buccal nerve. b) Motor branches, the masseteric nerve and deep temporal nerves and the nerve to the lateral pterygoid. From the posterior trunk: a) Auriculotemporal nerve b) Lingual nerve c) Inferior alveolar nerve
Meningeal branch or nervus spinosus:- • It enters the skull through the foramen spinosum with the middle meningeal artery and supplies the dura mater of the middle cranial fossa. Nerve to medial pterygoid:- • It arises close to the otic ganglion and supplies medial pterygoid from its deep surface. • This nerve gives a motor root to the otic ganglion which does not relay and supplies the tensor veli palatine, and the tensor tympani muscles. Buccal Nerve:- • It is the only sensory branch of the anterior division of the mandibular nerve.
• It passes between the two heads of the lateral pterygoid , runs downwards and forwards , and supplies the skin of cheek, mucous membrane related to the buccinator. • It also supplies the labial aspect of the gums of molar and premolar teeth.
Masseteric nerve :- • It emerges at the upper border of the lateral pterygoid muscle just in front of the temporomandibular joint, passes laterally through the mandibular notch in company with the masseteric vessels, and enters the deep surface of the masseter. • It also supplies the temporomandibular joint.
Deep temporal nerves:- • These are two nerves , anterior and posterior. • They pass between the skull and the lateral pterygoid, and enter the deep surface of the temporalis. Nerve to lateral pterygoid:- • Nerve to the lateral pterygoid enters the deep surface of the muscle. Auriculotemporal nerve:- • It arises by two roots which run backwards, encircle the middle meningeal artery, and unite to form a single trunk. • The auricular part of the nerve supplies the skin of the tragus, and upper parts of the pinna, the external acoustic meatus and the tympanic membrane.
• The temporal part supplies the skin of the temple. • In addition, the auriculotemporal nerve also supplies the parotid gland and the temporomandibular joint.
Lingual nerve:- • One of the two terminal branches of the posterior division of the mandibular nerve. • Sensory to the anterior two thirds of the tongue and to the floor of the mouth. • The fibres of chorda tympani which is secretomotor to the submandibular and sublingual salivary glands and gustatory to the anterior two thirds of the tongue , are also distributed through the lingual nerve. Course :- • Begins 1 cm below the skull . • At 2 cm below the skull, it is joined by chorda tympani nerve at an acute angle, then it lies in contact with mandible medial to third molar tooth. • Finally it lies on surface of hyoglossus and genioglossus to reach the tongue.
Inferior alveolar nerve:- • It is the largest terminal branch of the posterior division of the mandibular nerve. • Runs vertically downwards lateral to the medial pterygoid and to the sphenomandibular ligament. • It enters the mandibular foramen and runs in the mandibular canal. • It is accompanied by the inferior alveolar artery. • Branches :- mylohyoid branch, branches that supply the lower teeth and gums, mental nerve.
BRANCHES OF THE MANDIBULAR NERVE (CN V3) Muscular Sensory Other Temporalis and masseter Meningeal Auriculotemporal Taste Medial and lateral pterygoid Inferior alveolar Secretory Tensor veli palatine and tensor tympani Lingual Articular Mylohyoid and digastric Buccal
Trigeminal nerve and its course
APPLIED ASPECT • Trigeminal Neuralgia:- • Sudden,lancinating,usually unilateral, severe brief stabbing recurrent pain in the distribution of one or more branches of Vth cranial nerve. Etiology :- • Most cases are idiopathic. • Compression of nerve in root entry zone. • Uncommonly by nerve demyelination n post herpetic neuralgia
CLINICAL CHARACTERISTICS • Incidence – 4 in 100000 person. • Age – late middle age (5th or 6th decade) • Female predilection. • Division of trigeminal nerve involvement. • V3 most commonly involved followed by V2. • V1 is rarely involved • Predilection for right side is noted (60%).
• Diagnostic criteria for Trigeminal neuralgia ( by: Sweet in 1987) • The pain is paroxysmal. • The pain may be provoked by light touch to the face (Trigger zone). • The pain is confined to trigeminal distribution. • The pain is unilateral.
HISTORY AND SOCIETY • Trigeminal neuralgia was first described by physician John Fothergill and treated surgically by John Murray Carnochan, both of whom were graduates of the University of Edinburgh Medical School. • Historically TN has been called "suicide disease" due to studies by Dr Harvey Cushing which demonstrated 0.6% mortality involving 123 cases of TN during 1896 and 1912. • Salman Khan, one of India's biggest film stars, was diagnosed with TN in 2011, resulting in tremendous media coverage in the country and abroad. He underwent surgery in the US.
TREATMENT • Drug therapy with carbamazepine 1. Initial treatment of choice. 2. 100 mg single daily dose and increased gradually by 100 mg daily every 1 or 2 days until substantial pain relief. • If carbamazepine is not well tolerated then phenytoin 300 mg to 400 mg daily. • Baclofen 5 mg to 10 mg TID either alone or in combination with carbamazepine or phenytoin.
• Surgical therapy -Peripheral neurectomy -Radiofrequency thermal Rhizotomy • Injection of glycerol • Microvascular Decompression
FREY’S SYNDROME • Clinical manifestation: Sweating, flushing, sense of warmth in the temporal area during eating • Etiology:- • Damage to auriculotemporal nerve • Due to trauma or parotitis.
a) Topical agents: anticholinergic preparation commercial antiperspirants like scopolamine and glycopyrolate. b) Injection of botulinum A toxin. c) Surgical procedures: Auriculotemporal nerve section.
2. Damage to the nasociliary branch can produce loss of the protective corneal reflex with serious consequences to the eye. 3. The motor part of the mandibular nerve is tested clinically by asking the patient to clench hisher teeth and then feeling for the contracting masseter and temporalis muscles on the two sides. 4. If one Masseter is paralysed, the jaw deviates to the paralysed side, on opening the mouth by the action of normal lateral Pterygoid of the Opposite side. The activity of the Pterygoid muscle is tested by asking the patient to move the chin from side to side.
5. Lingual nerve lies in contact with the mandible, medial to the third molar tooth. In extraction of malposed "wisdom tooth" care must be taken not to injure the lingual nerve. 6. Post-herpetic neuralgia: This unfortunate sequela occurs most frequently in elderly patients as a result of scarring of nerve.
7. Trotter's syndrome - Carcinoma of the nasopharynx often producing trigeminal neuralgia like pain in the mandible, tongue & side of the head along with the middle ear deafness. 8. Wallenberg syndrome : Also called the lateral medullary syndrome, a stroke causes loss of pain / temperature sensation from one side of the face and the other side of the body.
CONCLUSION • An understanding of the management of pain in dentistry requires thorough knowledge of the fifth cranial nerve. • The right and left trigeminal nerves provide, among other functions, an overwhelming majority of sensory innervation from teeth, bone and soft tissues of the oral cavity.
TAKE HOME MESSAGE • Disorders of Trigeminal nerve are not rare. Knowing about it will help in formulating appropriate diagnosis and treatment. • Nerve blocks given for carrying various dental procedures involves the various branches of Trigeminal nerve, Hence to avoid any complications ,one needs to have a knowledge about the course and branches of the nerve .
REFERENCES • BD Chaurasia’s Human Anatomy – 4th edition • Textbook of Anatomy – I.B Singh -4th edition • Grays Anatomy • Atlas of Anatomy- Joseph J. Warner • Sicher and DuBRUL’s Oral Anatomy 8th edition. • Essentials of medical pharmacology- K.D tripathi 6th edition. • Handbook of local anaesthesia by stanley malamed
Thank you !

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Trigeminal nerve and its course

  • 2. TRIGEMINAL NERVE Presented by:- Dr. Shruti Mishra MDS 1st year Dept. of conservative and Endodontics
  • 3. GUIDED BY:- • Dr. Gopal Tawani (Reader and Guide) • Dr. Manoj Chandak (Professor and HOD) • Dr. Pradnya Nikhade (Professor) • Dr. Ajay Saxena (Professor) • Dr. Anuja Ikhar (Reader) • Dr. Neelam Chandwani (Reader) • Dr. Aditya Patel (Reader)
  • 4. CONTENTS • Introduction. • Trigeminal Ganglion. • Origin & Attachments of the Trigeminal Nerve • Branches of the Trigeminal Nerve. Course. Branches. Innervations. • Applied Anatomy. • Summary
  • 5. SPECIFIC LEARNING OBJECTIVES S/N Learning Objectives Domain Level Criteria 1. Intracranial course Cognitive Must know All 2. Trigeminal ganglion Cognitive Must know All 3. Origin and attachments of the trigeminal nerve Cognitive Must know All 4. Branches of the nerve Cognitive Must know All 5. Course and innervations Cognitive Must know All 6. Applied anatomy Cognitive Must know All
  • 6. INTRODUCTION • The word ‘Trigemina’ meaning ‘Threefold’ gives the V Cranial Nerve its name – The Trigeminal or Trifacial Nerve as it forms 3 divisions:- 1. The Opthalmic(sensory) 2. The Maxillary(sensory) & 3. The Mandibular nerve(Sensory,motor). • It is the largest of all the Cranial Nerves, & of mixed variety having a large sensory root & a small motor root. • As major general sensory nerves of face, it transmits afferent impulses from Touch, Temperature & Pain receptors.
  • 7. Figure showing inferior view of the brain showing cranial nerves and the organs and tissue they innervate
  • 8. • It is composed of a small motor root and a considerably larger (tripartite) sensory root. • The motor root supplies the muscles of mastication and other muscles in the region. • The three branches of sensory root supply the skin of the entire face and the mucous membrane of the cranial viscera and oral cavity, except for the pharynx and base of the tongue.
  • 9. ORIGIN • Cell bodies of sensory neurons of all three divisions are located in the large Trigeminal (or Semilunar or Gasserian or Gasser's) Ganglion. • The mandibular division also contains motor fibers that innervate the muscles of mastication. Gaserrian ganglion
  • 10. TRIGEMINAL / SEMILUNAR / GASSERIAN GANGLION • In 1765, Anton Balthasar Raymund Hirsch, described the Gasserian ganglion, naming it in honor of his professor “Gasser’ a Professor of Anatomy at the University of Vienna. • It is the sensory ganglion of the Vth cranial nerve. • The ganglion is Flat, Crescentric Or Semilunar in shape, measuring 1 x 2 cms with its convexity directed anterolaterally. • The three divisions of the trigeminal nerve emerge from this convexity.
  • 11. Situation & Meningeal Relations : • The ganglion lies at a depth of 4.5 – 5 cms from the lateral aspect of head, at the posterior extremity of the Zygomatic arch. • It occupies a special space of dura mater, called the Trigeminal (or Meckel’s) Cave covering the trigeminal impression on the anterior surface of the petrous temporal bone near its apex. Clinical Significance : • After recovery from a primary herpes infection, the virus is not cleared from the body, but rather lies dormant in a non-replicating state within the trigeminal ganglion. Thus, herpes zoster may follow from Chickenpox.
  • 12. Opthamlmic nerve V1 Maxillary nerve V2 Mandibular nerve V3 Trigeminal ganglion Trigeminal nerve Trigeminal Nerve in the interior of the base of the cranium
  • 13. Sensory root Mouth of Meckel’s cave Trigeminal ganglion Greater pertrosal nerve Lesser petrosal nerve Mandibular nerve Maxillary nerve Opthalmic nerve Lacrimal nerve Frontal nerve Supraorbital nerve Supratroch lear nerve Trigeminal nerve in the Middle Cranial Fossa
  • 14. ORIGIN & ATTACHMENT • The Trigeminal nerve is attached to the lateral part of the pons by its 2 roots, motor & sensory to its 4 nuclei : 1. Principle sensory nucleus. 2. Mesencephalic nucleus. 3. Motor nucleus. 4. Spinal nucleus. pons Trigeminal ganglion
  • 15. SPINAL NUCLEUS • Takes pain and temperature sensations from most of the face area which relay here. • The crossed fibres are called trigeminal lemniscus which go to ventroposterior nucleus of thalamus for another relay, to finally terminate in lower part of postcentral gyrus.
  • 16. SUPERIOR SENSORY NUCLEUS • Fibres carrying touch and pressure relay in this nucleus. • Remaining path is same as that of the spinal nucleus.
  • 17. MESENCEPHALIC NUCLEUS • This nucleus extends from pons till the midbrain. • Receives proprioceptive impulses from muscles of mastication, temporomandibular joint and teeth.
  • 19. Pons Hypoglossal nerve Sensory root Motor root Vagus nerve Superficial origin of trigeminal nerve
  • 20. SENSORY COMPONENTS OF V NERVE • Sensations of pain, temperature, touch and pressure from skin of face, mucous membrane of nose, most of the tongue, paranasal air sinuses travel along axons. • Their cell bodies lie in the V ganglion. • This ganglion is similar to the spinal ganglia of other nerves. • It lies at the apex of petrous temporal bone in a dural cave, the Meckel’s cave. • Peripheral processes form the three nerves.
  • 21. Sensory Root : • The large sensory root (portio major) arise from the Semilunar (Gasserian) ganglion & enters the brainstem via the side of the Pons. • The ganglion with its unipolar neurons forms Central & Peripheral processes. • The peripheral branches form the opthalmic, maxillary & mandibular divisions of the nerve while the central branches are the sensory roots of the trigeminal nerve V1 V2 V3
  • 22. • The central processes of V ganglion form sensory root. • Some fibres ascend and other descend. • Ascending fibres end in superior sensory nucleus. • Descending fibres end in the spinal nucleus of V nerve.
  • 23. • Pain and temperature reach spinal nucleus. • Touch and pressure sensations go to superior sensory nucleus. • Opthalmic nerve fibres end in the inferior part, maxillary nerve fibres end in the middle part and mandibular nerve fibres terminate in the upper part of the spinal nucleus.
  • 24. MOTOR COMPONENT • The motor nucleus receives impulses from the right and left cerebral hemispheres, red nucleus and mesencephalic nucleus. • Fibres of motor root supply four muscles of mastication and four other muscles. • It supplies the following muscles : - Muscles of mastication:- 1. Mylohyoid. 2. Ant belly of the diagastric. 3. Tensor tympani. 4. Tensor veli palatini
  • 25. • The small motor root (portio minor) arises separately from the sensory root, originating in the motor nucleus located in the upper pons and medulla oblongata. Its fibers, forming a small nerve root travels anteriorly along with, but entirely separate from, the larger sensory root to the region of trigeminal ganglion. Here the nerve passes latero-inferior direction under the ganglion towards the foramen ovale, through which it leaves the MIDDLE CRANIAL FOSSA along the mandibular nerve. Just after leaving the skull, the motor root unites with the sensory root of the mandibular division to form a single trunk.
  • 26. BRANCHES OF THE TRIGEMINAL NERVE • The Trigeminal Nerve forms three divisions : 1) The Opthalmic 2) The Maxillary & 3) The Mandibular Nerves. • All of the three are chiefly sensory in nature but the mandibular division also contains motor fibres that innervate the muscles of mastication.
  • 27. The general pathway of the trigeminal nerve and its motor and sensory roots and three divisions
  • 28. Various branches of trigeminal nerve
  • 29. OPTHALMIC NERVE (V1) • Ist branch of trigeminal nerve. • Sensory in nature. • Smallest branch(2.5cms long) SUPPLIES :- 1.Eyeball 2.Conjuctiva 3.Lacrimal Gland 4.Parts of the mucous membrane of the nose and Paranasal Sinuses 5.Skin of the forehead, eyelid and nose. Just before the ophthalmic nerve passes through the superior orbital fissure it divides into its three main branches: a. Frontal b. Lacrimal and c. Naso-cilliary nerves
  • 30. COURSE • It courses anteriorly in the lateral wall of the cavernous sinus to the medial part of the superior orbital fissure through which it enters the orbit. • It also gives off communication branches to the Oculomotor, Trochlear and Abducent cranial nerves. As the ophthalmic division passes forward from the cavernous sinus, it divides into three branch’s: Lacrimal, Frontal and Nasociliary Nerves.
  • 32. • The internal branch, the nasociliary nerve , follows the medial border of the orbital roof, releases branches to the nasal cavity, and ends on the skin at the root of the nose. • The intermediate branch, the frontal nerve , courses straight anteriorly to reach the skin of the forehead. • Finally the external branch, the lacrimal nerve, runs anteriorly and laterally along the border of roof the orbit toward the lacrimal gland and to the skin at the outer corner of the eye.
  • 33. • Branches : a) Lacrimal nerve b) Frontal nerve • Supraorbital • Supratrochlear c) Nasocilliary nerve 1) Branches in the Orbit - Long root of ciliary ganglion - Long ciliary nerve - Posterior ethmoidal - Anterior ethmoidal -Internal nasal branches -External nasal branches
  • 34. 2) Branches arising in the nasal cavity 3) Terminal branches of the opthalmic division on the face.
  • 35. I) LACRIMAL NERVE • Smallest of the three branches. • It passes into the orbit at the lateral angle of the superior orbital fissure & then courses in an anterolateral direction to reach the lacrimal gland. Innervation : a) Skin of the upper eyelid and lateral part of the eyebrow region b) Conjunctiva of the lateral part of the upper eyelid.
  • 36. II) FRONTAL NERVE • The largest of the three branches, & appears to be a direct continuation of the ophthalmic division. It enters the orbit by way of the superior orbital fissure. At about the middle of the orbit, the frontal nerve divides into two branches: 1) Supraorbital nerve : • Larger branch of the frontal nerve. • It passes forward and leaves the orbit through the supraorbital foramen Innervation :- a) Medial part of the upper eyelid & the lower medial part of the forehead. b) Conjunctiva of the upper eyelid.
  • 37. 2) Supratrochlear nerve • The smallest branch of the frontal nerve. • It passes toward the upper medial angle of the orbit. Innervation : a) Skin of the Upper Eyelid and the skin of the forehead and scalp as far back as the vertex of the skull. b) Lining of the frontal sinus.
  • 38. III ) NASOCILIARY NERVE • It is the third main branch of the ophthalmic division. It enters the orbit through the Superior Orbital Fissure. • Its branches are divided into those arising in the orbit, in the nasal cavity, and on the face. Innervation :- a. Long ciliary branch : -Sensory from the eyeball and ciliary ganglion. b. Infratrochlear nerve : -Upper and lower eyelid and from the side of the nose. -Conjunctiva and the lacrimal sac. c. Ethmoid branches : Sensory from the lining of the frontal & sphenoid sinus and of the anterior & posterior ethmoid cells.
  • 39. d. Internal branches : Sensory from the anterior portion of the septum and lateral walls of the nasal cavity. e. External nasal branch : Sensory from the tip of the nose. A) Branches in the orbit : 1. Long root of the ciliary ganglion: The long, or sensory, root arises from the nasociliary nerve. It contains sensory fibers, which pass through the ganglion without synapsing and continue on to the eyeball by means of the short ciliary nerves. 2. Long ciliary nerves: There are usually two or three long ciliary nerves branching from the nasociliary nerve. They are distributed to the iris & cornea.
  • 40. 3. Posterior ethmoid nerve : It enters the posterior ethmoid canal to be distributed to the mucous membrane lining the posterior ethmoidal cells and the sphenoid sinus. 4. Anterior ethmoid nerve : It continues anteriorly along the medial wall of the orbit. In the upper part of the nasal cavity, the ethmoid nerve divides into two sets of anterior nasal branches: a) Internal nasal branches : In turn, divide in the upper anterior part of the nasal cavity into two divisions : - Medial or septal branches. - Lateral branches. b) External nasal branches : At the border between the lower edge of the nasal bone and the upper edge of the lateral nasal cartilage, the external nasal branch passes externally.
  • 41. B. Branches arising in the nasal cavity:- • The branches of the nasociliary nerve that arise in the nasal cavity supply the mucous membrane lining the cavity. C. Terminal branches of the ophthalmic division on the face:- • These branches course below the trochlear nerve to supply sensory fibers to the skin of the medial parts of both eyelids, lacrimal sac, & the lacrimal caruncle. • These fibers supply the skin over the side of the bridge of nose.
  • 42. Main branches of ophthalmic nerve
  • 43. MAXILLARY NERVE (V2) • The maxillary nerve is entirely sensory in function. Intracranial course : • It originates at the middle of the semilunar ganglion & continues forward in the lower part of the cavernous sinus. Extracranial course : • It then passes to the Foramen Rotundum, through which it leaves the cranial fossa and enters the Pterygopalatine Fossa. It enters the Inferior Orbital Fissure to pass into the orbital cavity. Here it turns laterally in a groove on the orbital surface of the maxilla, called the infraorbital groove.
  • 45. Maxillary nerve (V2) Cranial cavity Pterygopalatine fossa Infraorbital canal Face / Terminal branches Meningeal Pterygopalatine Zygomatic Posterior superior alveolar Middle superior alveolar Anterior superior alveolar Palpebral Nasal Superior labial
  • 47. BRANCHES GIVEN IN THE PTERYGO PALATINE FOSSA Pterygopalatine nerve Zygomatic nerve Posterior superior alveolar nerve Orbital Nasal Pharyngeal Palatine Greater palatine Lesser palatine Nasopalatine nerve Zygomaticotemporal Zygomaticofacial
  • 48. I) Branches given off in the middle cranial fossa : • In the middle cranial fossa a small branch, the middle meningeal nerve, passes with the middle meningeal artery and its branches to supply the dura with sensory fibers. • Innervation : It sends a sensory branch to the dura.
  • 49. PTERYGOPALATINE NERVE • Enters the ganglion after a course of only 2-3 mm. • No synapse formation with the cells of the ganglion. • The superior posterior nasal branches are given off :- 1. Lateral nasal • Supplies upper and middle conchae. 2. Medial branch (nasopalatine) • Branches of the septal mucosa passes through the incisive canal to reach the oral cavity.
  • 50. NASOPALATINE NERVE • Exchanges fibers with anterior superior alveolar nerves and consequently may participate in the innervation of central incisor. • In the nasopalatine canal, the rt. And lt. palatine nerves approach each other and enter the oral cavity through the unpaired incisive foramen. • Supply a small anterior area of the palatine mucosa behind the incisor teeth , from one canine to another.
  • 51. MAIN PART OF THE PTERYGOPALATINE NERVE • Continues below the pterygopalatine ganglion. • Passes through the pterygopalatine fossa and canal. • Palatine nerves • Before reaching the lower oral end of the pterygopalatine canal, palatine nerve divides into one larger and one or two smaller branch. Larger branch smaller branch
  • 52. Palatine nerves Larger branch (anterior palatine nerve) Enters oral cavity through the major palatine foramen. Splits into numerous branches that spread fan wise • Anterior • Lateral • Medial Smaller branch Middle and posterior palatine nerves emerge through the lesser palatine foramen and supply the tonsil and the soft palate with sensory twigs
  • 53. INFRAORBITAL NERVE • Intermediate branch. • Passes through the pterygomaxillary fissure. • Reaches infratemporal fossa. • Leaves immediately through the inferior orbital fissure. • Enters the orbit to run in the infraorbital groove. • The groove is roofed to form the infraorbital canal, which leads the nerve to the infraorbital foramen to the superficial structures of face.
  • 54. BRANCHES OF INFRAORBITAL NERVE • Superior alveolar nerves. • Posterior superior alveolar nerve. • Middle superior alveolar nerve.
  • 55. SUPERIOR ALVEOLAR NERVES • Supplies upper teeth, their periodontal membrane and gingivae on the outer surface of the jaw. • In the base of the alveolar process the SAN exchange fibers and form a loose plexus – superior dental plexus. • Two terminal sets of branches:- 1. Dental nerves:- innervates the roots of the superior teeth by entering the apical foramen and branches in the dental pulp. 2. Interdental/ inter radicular nerves:- supplies b/w two adjacent teeth, supplies PDL. They end in the PDL at the furcation of roots.
  • 56. • Terminal branches :- • They spread fanwise:- 1) Palpebral branches :- turns upward into the eyelid. 2) Nose :- supply the lateral slope of the nose and nasal wing. 3) Upper lip :- 3 or 4 superior labial branches enter the lip between its muscles and mucous membrane.
  • 57. ZYGOMATIC NERVE • Division occurs either before or while the infraorbital nerve passes through the inferior orbital fissure. • In the orbit, it follows the lateral edge of the orbital floor anteriorly and laterally. • Sends upward branch to the lacrimal nerve. • Enters the zygomatic foramen and reaches the zygomatic bone. zygomatico- zygomaticotemporal facial
  • 59. MANDIBULAR NERVE (V3) • This is the largest of the three divisions of the trigeminal nerve. • It has both sensory and motor fibres.(Mixed nerve) • It is the nerve of first branchial arch and supplies all structures derived from the first branchial arch. • Otic and submandibular ganglia are associated with this nerve.
  • 60. COURSE AND RELATIONS • Mandibular nerve begins in the middle cranial fossa through a large sensory root and a small motor root. • The sensory root arises from the lateral part of the trigeminal ganglion, and leaves the cranial cavity through the foramen ovale. • The motor root lies deep to the trigeminal ganglion and to the sensory root. • It also passes through the foramen ovale to join the sensory root just below the foramen thus forming the main trunk.
  • 61. • The main trunk lies in the infratemporal fossa, on the tensor veli palatine, deep to the lateral pterygoid. • After a short course, the main trunk divides into a small anterior trunk and a large posterior trunk.
  • 63. BRANCHES From the main trunk:- a) Meningeal branch b) Nerve to medial pterygoid From the anterior trunk. a) A sensory branch, the buccal nerve. b) Motor branches, the masseteric nerve and deep temporal nerves and the nerve to the lateral pterygoid. From the posterior trunk: a) Auriculotemporal nerve b) Lingual nerve c) Inferior alveolar nerve
  • 64. Meningeal branch or nervus spinosus:- • It enters the skull through the foramen spinosum with the middle meningeal artery and supplies the dura mater of the middle cranial fossa. Nerve to medial pterygoid:- • It arises close to the otic ganglion and supplies medial pterygoid from its deep surface. • This nerve gives a motor root to the otic ganglion which does not relay and supplies the tensor veli palatine, and the tensor tympani muscles. Buccal Nerve:- • It is the only sensory branch of the anterior division of the mandibular nerve.
  • 65. • It passes between the two heads of the lateral pterygoid , runs downwards and forwards , and supplies the skin of cheek, mucous membrane related to the buccinator. • It also supplies the labial aspect of the gums of molar and premolar teeth.
  • 66. Masseteric nerve :- • It emerges at the upper border of the lateral pterygoid muscle just in front of the temporomandibular joint, passes laterally through the mandibular notch in company with the masseteric vessels, and enters the deep surface of the masseter. • It also supplies the temporomandibular joint.
  • 67. Deep temporal nerves:- • These are two nerves , anterior and posterior. • They pass between the skull and the lateral pterygoid, and enter the deep surface of the temporalis. Nerve to lateral pterygoid:- • Nerve to the lateral pterygoid enters the deep surface of the muscle. Auriculotemporal nerve:- • It arises by two roots which run backwards, encircle the middle meningeal artery, and unite to form a single trunk. • The auricular part of the nerve supplies the skin of the tragus, and upper parts of the pinna, the external acoustic meatus and the tympanic membrane.
  • 68. • The temporal part supplies the skin of the temple. • In addition, the auriculotemporal nerve also supplies the parotid gland and the temporomandibular joint.
  • 69. Lingual nerve:- • One of the two terminal branches of the posterior division of the mandibular nerve. • Sensory to the anterior two thirds of the tongue and to the floor of the mouth. • The fibres of chorda tympani which is secretomotor to the submandibular and sublingual salivary glands and gustatory to the anterior two thirds of the tongue , are also distributed through the lingual nerve. Course :- • Begins 1 cm below the skull . • At 2 cm below the skull, it is joined by chorda tympani nerve at an acute angle, then it lies in contact with mandible medial to third molar tooth. • Finally it lies on surface of hyoglossus and genioglossus to reach the tongue.
  • 70. Inferior alveolar nerve:- • It is the largest terminal branch of the posterior division of the mandibular nerve. • Runs vertically downwards lateral to the medial pterygoid and to the sphenomandibular ligament. • It enters the mandibular foramen and runs in the mandibular canal. • It is accompanied by the inferior alveolar artery. • Branches :- mylohyoid branch, branches that supply the lower teeth and gums, mental nerve.
  • 71. BRANCHES OF THE MANDIBULAR NERVE (CN V3) Muscular Sensory Other Temporalis and masseter Meningeal Auriculotemporal Taste Medial and lateral pterygoid Inferior alveolar Secretory Tensor veli palatine and tensor tympani Lingual Articular Mylohyoid and digastric Buccal
  • 73. APPLIED ASPECT • Trigeminal Neuralgia:- • Sudden,lancinating,usually unilateral, severe brief stabbing recurrent pain in the distribution of one or more branches of Vth cranial nerve. Etiology :- • Most cases are idiopathic. • Compression of nerve in root entry zone. • Uncommonly by nerve demyelination n post herpetic neuralgia
  • 74. CLINICAL CHARACTERISTICS • Incidence – 4 in 100000 person. • Age – late middle age (5th or 6th decade) • Female predilection. • Division of trigeminal nerve involvement. • V3 most commonly involved followed by V2. • V1 is rarely involved • Predilection for right side is noted (60%).
  • 75. • Diagnostic criteria for Trigeminal neuralgia ( by: Sweet in 1987) • The pain is paroxysmal. • The pain may be provoked by light touch to the face (Trigger zone). • The pain is confined to trigeminal distribution. • The pain is unilateral.
  • 76. HISTORY AND SOCIETY • Trigeminal neuralgia was first described by physician John Fothergill and treated surgically by John Murray Carnochan, both of whom were graduates of the University of Edinburgh Medical School. • Historically TN has been called "suicide disease" due to studies by Dr Harvey Cushing which demonstrated 0.6% mortality involving 123 cases of TN during 1896 and 1912. • Salman Khan, one of India's biggest film stars, was diagnosed with TN in 2011, resulting in tremendous media coverage in the country and abroad. He underwent surgery in the US.
  • 77. TREATMENT • Drug therapy with carbamazepine 1. Initial treatment of choice. 2. 100 mg single daily dose and increased gradually by 100 mg daily every 1 or 2 days until substantial pain relief. • If carbamazepine is not well tolerated then phenytoin 300 mg to 400 mg daily. • Baclofen 5 mg to 10 mg TID either alone or in combination with carbamazepine or phenytoin.
  • 78. • Surgical therapy -Peripheral neurectomy -Radiofrequency thermal Rhizotomy • Injection of glycerol • Microvascular Decompression
  • 79. FREY’S SYNDROME • Clinical manifestation: Sweating, flushing, sense of warmth in the temporal area during eating • Etiology:- • Damage to auriculotemporal nerve • Due to trauma or parotitis.
  • 80. a) Topical agents: anticholinergic preparation commercial antiperspirants like scopolamine and glycopyrolate. b) Injection of botulinum A toxin. c) Surgical procedures: Auriculotemporal nerve section.
  • 81. 2. Damage to the nasociliary branch can produce loss of the protective corneal reflex with serious consequences to the eye. 3. The motor part of the mandibular nerve is tested clinically by asking the patient to clench hisher teeth and then feeling for the contracting masseter and temporalis muscles on the two sides. 4. If one Masseter is paralysed, the jaw deviates to the paralysed side, on opening the mouth by the action of normal lateral Pterygoid of the Opposite side. The activity of the Pterygoid muscle is tested by asking the patient to move the chin from side to side.
  • 82. 5. Lingual nerve lies in contact with the mandible, medial to the third molar tooth. In extraction of malposed "wisdom tooth" care must be taken not to injure the lingual nerve. 6. Post-herpetic neuralgia: This unfortunate sequela occurs most frequently in elderly patients as a result of scarring of nerve.
  • 83. 7. Trotter's syndrome - Carcinoma of the nasopharynx often producing trigeminal neuralgia like pain in the mandible, tongue & side of the head along with the middle ear deafness. 8. Wallenberg syndrome : Also called the lateral medullary syndrome, a stroke causes loss of pain / temperature sensation from one side of the face and the other side of the body.
  • 84. CONCLUSION • An understanding of the management of pain in dentistry requires thorough knowledge of the fifth cranial nerve. • The right and left trigeminal nerves provide, among other functions, an overwhelming majority of sensory innervation from teeth, bone and soft tissues of the oral cavity.
  • 85. TAKE HOME MESSAGE • Disorders of Trigeminal nerve are not rare. Knowing about it will help in formulating appropriate diagnosis and treatment. • Nerve blocks given for carrying various dental procedures involves the various branches of Trigeminal nerve, Hence to avoid any complications ,one needs to have a knowledge about the course and branches of the nerve .
  • 86. REFERENCES • BD Chaurasia’s Human Anatomy – 4th edition • Textbook of Anatomy – I.B Singh -4th edition • Grays Anatomy • Atlas of Anatomy- Joseph J. Warner • Sicher and DuBRUL’s Oral Anatomy 8th edition. • Essentials of medical pharmacology- K.D tripathi 6th edition. • Handbook of local anaesthesia by stanley malamed

Editor's Notes

  • #32: Lacrimal nerve- supplies the lateral part of the upper eyelid and a small adjacent area of the skin. Frontal nerve- medial branch- skin of forehead, lateral branch- largest , supplies the greater lateral part of the forehead and skin of the scalp upward and backward to the vertex(highest point on the skull). Most medial branch- supplies upper eyelid near inner corner of the eye. Nasociliary – internal branch, sends communicating branch from the ciliary ganglion. Ethmoid nerve-ant. Ethmoid foramen . In nasal cavity, medial and lateral branches supply a small anterior area of the mucous membrane on the lateral nasal wall and on the nasal septum. Terminal branch – infratrochlear nerve- exchanges fibres with supratrochlear nerve and supplies the inner part of the upper eyelid and the adjacent skin at the root of the nose.
  • #59: Zygomatic nerve- sends upward branch to the lacrimal nerve. Enters the zygomatic orbital foramen and in the zygomatic bone divides to form zygomaticofacial nerve and zygomaticotemporal nerve. Infraorbital nerve – passes through the pterygomaxillary fissure and leaves through the inferior orbital fissure. Superior alveolar nerve- supply upper teeth and their PDL and gingivae on the outer surface of the jaw.it exchanges fibre to form a loose plexus called superior dental plexus , which terminates into dental nerves and interradicular nerves. Dental nerves supply the roots and branches in the dental pulp. And the interradicular nerves supply between the two adjacent teeth, supplies PDL and gingiva and interdental papilla and labial or buccal gingivae. They end in PDL at the furcation of the roots. Pterygopalatine nerve-divides into two –lateral and medial. The lateral branch supply upper and middle conchae and medial branch –nasoplatine nerve- upper central incisor.
  • #71: Mental nerve supplies the skin of the chin, and the skin and mucous membrane of the lower lip. Labial aspect of gums and canine and incisor teeth.
  • #74: -TN is a very typical example of orofacial neuralgia which follows the anatomic distribution of the trigeminal nerve. -Compression of nerve root by tumours or vascular anomalies like abnormal vessels, aneurysms,chronic meningeal inflammation. -uncommonly an area of demyelination as in multiple sclerosis may be the precipitant. -development of tn in young patient is suggestive of multiple sclerosis….but in most cases no organic lesion is identified n the etiology is labeled as idiopathic. -n very rarely due to herpes zoster causing post herpetic neuralgia
  • #75: Attacks do not occur during sleep. Pain often mimick odontogenic pain In extreme cases the patients have a motionless face – “frozen or mask like face” Pain is confined to one part of nerve.. Pain rarely crosses the midline.. Pain occurs in cycles.
  • #78: -Drug therapy with carbamazepine is the initial treatment of choice n its effective in 50%-70% of patients. -started as single daily dose of 100mg taken with food n increased gradually by 100mg daily every 1 to 2 days until substantial pain relief is achieved.do not exceed 1200 mg daily.maintenance dose kept at 200mg daily .side effects of carbamazepine is dizziness imbalance sedation n rarely agranulocutosis. -if treatment is effective continue for a month n then accordingly dose is tapered to the minimum effective level as soon as adequate control is achieved
  • #79: -Peripheral neurectomy i.e sectioning of the nerve at the mental foramen or at the supraorbital or infraorbital foramen.one of the earliest form of treatment .relief offered is only temporary so this form of treatment has not been used extensively in recent years. -radiofrequency thermal rhizotomy is the most widely applied procedure…it creates a heat lesion of the trigeminal ganglion. -injection of glycerol either into the peripheral nerve area or centrally into the trigeminal ganglion.both rhizotomy and injection of glycerol produce short term relief in 95 % of the patients -Microvascular compression newest procedures in the management of TN, requires suboccipital craniectomy i.e opening a keyhole in the mastoid area and freeing the trigeminal nerve from the compression or the pulsating artery n then a piece of teflon is placed between them.initial efficacy rate is 80% n recurrence rate are lowest 25% in 5 years among the other invasive treatments.
  • #80: -Freys syndrome is an unusual phenomenon which arises as a result of damage to the auriculotemporal nerve The patient exhibits flushing and sweating of the involved side of the face in the temporal area during eating . -the syndrome follows some surgical operation such as removal of the parotid gland or the ramus of the mandible or a parotitis of some type that damage the auriculotemporal nerve.normally damaged nerve fibres eventually heal themselves .in freys syndrome it is believe that the damaged nerve fibre regenerate abnormally n getting connected to the sweat glands on the skin.so the parasympathetic nerves that normally tells the parotid gland to produce saliva in response to tasting food will now respond by instructing the sweat glands to produce sweat n the blood vessels to widen.
  • #81: Although Frey syndrome can be mild n well tolerated it can cause excessive discomfort.so treatment is symptomatic directed towards relief of symptoms. In the last decade injection of botulinum A toxin in the affected skin has become an established therapy as it causes suppression of sweating n causes no side effect.However the effect of the toxin is not permanent n last on an average of 9 to 12 months. Surgical excision of the affected skin n interposition or insertion of new tissues to the affected area has been described but are considered risky becoz of the presence of facial nerve fibres .