FACIAL & TRIGEMINAL NERVE 2

TRIGEMINAL NERVE.FACIAL NERVE.

GUIDED BY:Dr.Adarsh Desai.Dr.Ravi Kalola.

PREPARED BY:Aswathi Krishna.

MANDIBULAR NERVE V3

Trigeminal

Ganglion

Ophthalmic Nerve V1

Maxillary Nerve V2

INTRODUCTION The trigeminal nerve is the largest of the twelve

cranial nerves. It has mainly 3 branches(Ophthalmic V1, Maxillary V2

and Mandibular V3) . It is composed of small motor nerve and large

sensory nerve. The 3 nerves arise from a large Semilunar (OR

Gasserian) Trigeminal Ganglion. The motor root supplies the muscles of mastication

and other muscles in the region. The 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.

Brainstemnuclei ofTrigeminal nerve

Semilunar Trigeminalganglion

Ophthalmicdivision ofTrigeminalnerve (V1)

Maxillarydivision ofTrigeminalnerve (V2)

Mandibulardivision ofTrigeminalnerve (V3)

& other

MOTOR ROOT

1. It consists of fibres that have their origin in2. In the motor nucleus located in the upper pons. 3. it passes below to the foramen ovale , through4. which it passes to join the mandibular division 5. Immediately below the base of the skull.6. Supplies : muscles of mastication.

SENSORY ROOT The sensory root fibres of the trigeminal nerve

arise from the semilunar ganglion . Two ganglia are present, they are located in

Meckel’s cavity, on the anterior surface of the petrous portion of the temporal bone.

The ganglia are flat and crescent shaped. The central branches leave the semilunar ganglion

and pass back and enter the pons , where they divide into ascending and descending fibres.

1.Ophthalmic Division (V1)->Travels anteriorly in the lateral wall of the cavernous sinus to the medial part of the superior orbital fissure, through which it exits the skull into the orbit.

2.Maxillary Division (V2)->Travels anteriorly and downward to exit the cranium through the foramen rotundum into the upper portion of the pterygopalatine fossa.

3.Mandibular Division (V3)->Travels almost directly downward to exit the skull, along with the motor root, through the foramen ovale.These two roots then intermingle, forming one nerve trunk that enters the infratemporal fossa.

On exiting the cranium through their respective foramen, the three divisions of the trigeminal nerve divide into multitude of branches.

OPHTHALMIC NERVE V1

V1 -GSA






•The ophthalmic division is the first branch of the trigeminal nerve.•The ophthalmic nerve arise from the semilunar ganglion in the middle cranial fossa. •It is the smallest of the three division.•The ophthalmic nerve passes forward in the lateral wall of the cavernous sinus and leaves the anterior medial part of the ganglion.•It divides into: 1-Frontal 2- Lacrimal 3-Nasociliary nerves

1. Frontal nerve :-Passes forward on the superior surface of the levator palpebrae superioris• Divides into the:

A-Supraorbital nerve -largest branch of the frontal nerve.• passes forward and leaves the orbit through the supraorbital foramen.•Supplies the skin of upper eyelid , forehead, and anterior scalp region to the vertex of the skull.

B-Supratrochlear nerve -Smallest branch of frontal nerve - Supplies : skin of the lower and medial forehead,skin of medial aspect of upper eyelid, conjunctiva.

2. Lacrimal Nerve • It is the smallest of three branches .• It passes into the orbit at the lateral angle of the superior orbital fissure .• It supplies to lacrimal gland

3. Naso-Cilliary Nerve•Enters the orbit through superior orbital fissure. • It Passes medially above the optic nerve.•It gives 5 branches (a)long (c)Nerve to ciliary ganglion (d)Infratrochlear -> both eyelids, side of nose, lacrimal sac. (e)Anterior ethmoidal -> Middle and anterior ethmoidal sinuses, Medial internal nasal, Lateral internal nasal, External nasal to skin of ala of vestibule and tip of nose.

V2 -GSA

Maxillary Nerve V2






Maxillary Nerve = V2

COURSE The maxillary division of the trigeminal nerve is entirely sensory in

function. The maxillary nerve originates at the middle of the semilunar

ganglion and continues forward in the lower part of the cavernous sinus.

It then passes to foramen rotundum through which it leaves the cranial fossa and enters the pterygopalatine fossa.

It enters the inferior orbital fissure to pass into orbital cavity.Here it turns laterally in a groove on the orbital surface of maxilla, called the infraorbital groove.

Continuing forward, the second division emerges on the anterior surface of the maxilla through the infraorbital foramen, where it divides.

In its course from the semilunar ganglion, the maxillary division gives off branches in four regions.

1)Middle Cranial Fossa 2)Pterygopalatine Fossa 3)Infraorbital Groove And Canal 4)On The Face (Terminal Branches)

1.BRANCHES IN 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.

2.BRANCHES IN THE PTERYGOPALATINE FOSSAA)ZYGOMATIC NERVE The zygomatic nerve leaves the second division in the

pterygopalatine fossa and passes anteriorly and laterally through the inferior orbital fissure into the orbit.

Here it divides into two parts: 1)Zygomaticofacial Nerve: Passes forward on the lateral

orbital foramen and pierces the orbicularis oculi muscle. Supplies-:Sensory fibers to the skin over the

prominence of the zygomatic bone. 2)Zygomaticotemporal Nerve: It leaves the orbit

between the great wing of the sphenoid and the zygomatic bone to enter the temporal fossa.

Supplies-: Sensory fibers to the skin over the anterior temporal fossa region.

B)Pterygopalatine (Sphenopalatine) Nerves These are two short nerve trunks that unite at the

pterygopalatine ganglion and are then redistributed into several branches.

These nerves also serve as important functional communications between the ganglion and the maxillary nerve.

Postganglionic secretomotor fibers from the pterygopalatine ganglion pass by means of these nerves back along the maxillary nerve to the zygomatic nerve, through which they are routed to the lacrimal nerve and the lacrimal gland.

The branches of pterygopalatine nerves are divided into three groups:

1)Orbital 2)Nasal 3)Palatine

1)Orbital Branches It supplies the periosteum of the orbit ,and the mucous membrane .n2)Nasal Branches : In nasal cavity, branches divide into: A.Posterior Superior Lateral Nasal Branches : These branches transmit

sensory impulse from the mucous membrane of nasal septum and posterior ethmoid cells.

B.Medial Or Septal Branch : This branch passes downward and forward. It transmits sensory impulses from the mucous membrane over the vomer. It then descends in the incisal canal and ramifies in the mucous membrane of the premaxillary region of the hard palate.

3)Palatine Branches : It descend in the pterygopalatine canal, where the fibers usually divide into three parts.

A.Greater Or Anterior Palatine Nerve : Emerges on hard palate by passing through greater palatine foramen and course in anterior direction between hard palate and mucoperiosteum to Supply Major part of of hard palate and palatine gingivae.

B.Middle Palatine Nerve : Emerges from lesser palatine foramen. Its fibers are sensory to mucous membrane of soft palate.

C.Posterior Palatine Fibers : Emerging from lesser palatine foramen, goes to mucous membrane of tonsillar area as part of sensory supply to tonsil itself.

C)Posterior Superior Alveolar Branches: Two or three branches leave maxillary division just

before it enters inferior orbital fissure. They pass downward and continue on posterior

surface of maxilla. In the bone, the nerve passes down the

posterolateral wall of maxillary sinus, giving off sensory fibers to mucous membrane of sinus. It then supplies maxillary molars and their gingivae.

Within the depths of alveoli, or tooth sockets, some nerve filaments pass to supply the periodontal membranes; whereas others, pulpal fibers, pass through apical foramina of roots of the molar teeth to supply the dental pulps.

3.BRANCHES IN INFRAORBITAL GROOVE AND CANAL The nerve in the infraorbital groove and canal known as the

infraorbital nerve and gives off two branches. 1)Middle Superior Alveolar Nerve : Within mucous membrane

of maxillary sinus it join with other alveolar nerves and form superior dental plexus of nerves.

The site of origin of these nerve varies from posterior portion of infraorbital canal to anterior portion, near infraorbital foramen.

The nerve provides sensory innervation to 2 maxillary premolar and, perhaps, to mesiobuccal root of first molar and periodontal tissues, buccal soft tissue, and bone in premolar region.

2)Anterior Superior Alveolar Nerve : A relatively large branch descend within anterior wall of maxillary sinus, it provides pulpal innervation to central and lateral incisors and canine, and sensory innervation to periodontal tissues, buccal bone, and mucous membranes of these teeth.

4.TERMINAL BRANCHES OF MAXILLARY DIVISION ON FACE As infraorbital nerve is about to emerge from

infraorbital foramen on front of maxilla, it divides into 3 terminal nerve branches.

1)Inferior Palpebral Branches: two or three in number , the branches pass upward.

Supplies: Sensory fibers to skin of lower eyelid and its conjunctiva.

2)External Or Lateral Nasal Branches:The external or lateral nasal branches pass to the skin of side of nose.

3)Superior Labial Branches:Usually two or three in number, the branches are distributed to the skin and mucous membrane of the upper lip.

V3 -GSA

Mandibular Nerve V3

COURSE The Mandibular Division of trigeminal nerve is the

largest of threedivisions. It is formed by union of Large Sensory(Afferent)

bundle of fibers and a Small Motor(Efferent) bundle of fibers.

The sensory root fibers are peripheral extensions of unipolar cells located in the semilunar ganglion.

The motor root fibers are derived from motor cells located in medulla oblongata in middle cranial fossa

The branches of Mandibular Division May be divided into 2 groups.

1)Branches from Undivided Nerve 2)Branches from Divided Nerve {Anterior And

Posterior Division}

1.BRANCHES FROM UNDIVIDED NERVEA)Nerve Spinosus : Arise outside the skull and then

passes into middle cranial fossa. Supplies: Dura And The Mastoid Cells.

B)Nerve To Internal Pterygoid Muscle : A branch of motor root passes to innervate the internal pterygoid muscle.

This branch passes without interruption to innervate The Tensor Veli Palatini And The Tensor Tympani Muscles.

GSA

GSA

GSA

GSA

SVE

SVE

**

** tensor tympani & tensor palati

SVE

2.BRANCHES FROM DIVIDED NERVE Below the level of Undivided part of Mandibular Division, the

trunk separates into 2 parts: Anterior And Posterior Divisions.

A)Anterior Dision : It is smaller than posterior division. It passes downward and forward, where it divided into four branches.

1.Pterygoid Nerve : It enters the medial side of external pterygoid muscle to provide its motor nerve supply.

2.Masseter Nerve : It passes above the external pterygoid to traverse the mandibular notch and enter the deep side of masseter muscle.

3.Nerve To The Temporal Muscle: (a)Anterior Deep Temporal Nerve : It passes upward and

crosses the infratemporal crest of sphenoid bone. It ends in the deep part of the temporal muscle.

(b)Posterior Deep Temporal Nerve :It passes upward to deep part of the temporal muscle.

4.Buccal Nerve : It passes downward, anteriorly and laterally between 2 heads of external pterygoid muscle. •At the level of occlusal plane of mandibular second and third molars, it divides into several branches that divide on buccinator muscle.•It then sends Sensory fibers to mucous membrane of cheek region.Others Sensory fibers pass into the retromolar triangle, providing sensory innervation to buccal gingiva of mandibular molars and mucobuccal fold in that region.•The Buccal Nerve Does Not Innervate Buccinator Muscle (By Facial Nerve)•Almost entire mucosa of cheek is supplied by buccal nerve.

B)Posterior Division : The larger posterior division is mainly sensory but also carries some motor components.

This division extends downward and medially and then divided into 3 branches.

1.Auriculotemporal Nerve

2.Lingual Nerve

3.Inferior Alveolar Nerve

1.Auriculotemporal Nerve : The nerve arises by medial and lateral root which embrace the middle meningeal artery and unite behind the artery just below foramen spinosum.

The united nerve passes posteriorly, deep to external pterygoid muscle, and then between the sphenomandibular ligament and neck of condyle of the mandible.

It traverses the upper deep part of parotid gland or its fascia and then crosses the posterior root of zygomatic arch.

It passes with superficial temporal artery in its upward course and divide into numerous branches, to the tragus of pinna of external ear, to scalp about ear, and as far upward as vertex of skull.

Branches Of Auriculotemporal Nerve : 5 branches

1>Parotid Branches : As the nerve passes the parotid gland, it gives off sensory, secretory, and vasomotor fibers to gland.

2>Articular Branches : 1 or 2 twigs of sensory fibers pass from auriculotemporal nerve and enters posterior part of Temporomandibular Joint.

3>Auricular Branches : The Anterior Auricular Branches are usually 2. They are sensory fibers supplying skin of helix and tragus.

4>Meatal Branches : Two small branches usually supply skin lining meatus and tympanic membrane.

5>Terminal Branches : The major part of filaments of auriculotemporal nerve pass to supply the scalp over the temporal region.

LINGUAL NERVE :

1. Smaller branch 2 terminal branch of

posterior division of mandibular nerve.2.Passes medially to external pteryigoid

muscle.3.Lies b/w internal pterygoid muscle &

ramus of mandible.4.Contributes sensory fibers to mucous

membrane of the floor of the mouth & gingiva

on lingual surface of ramus of mandible.

INFERIOR ALVEOLAR NERVE.1.Largest branch of posterior division of mandibular part of trigeminal nerve.2.Passes downward on medial side of external pterygoid muscle & medial side of mandibular ramus.3.In alveolar canal it gives branches to mandibular teeth as apical fibers.

FACIAL NERVE

FACIAL NERVE It is the 7th cranial nerve. It is the nerve of the 2nd branchial arch.

COURSE AND RELATIONS The facial nerve is attached to the

brainstem by two roots, motor and sensory.

The sensory root is also called the nervus intermedius.

The two roots of the facial nerve are attached to the lateral part of the lower border of the pons just medial to the eight cranial nerve.

The two roots run laterally and forwards, with the 8th nerve to reach the internal acoustic meatus.

In the meatus, the motor root lies in a groove on the eight nerve, with the sensory root intervening.

Here the seventh and eighth nerves are accompanied by the labyrinthine vessels.

At the bottom or fundus of the meatus, the two roots, sensory and motor, fuse to form a single trunk, which lies in the petrous temporal bone.

.Within the canal the course of the nerve can be divided into three parts by two bends.

.The 1st part is directed laterally above the vestibule .

.THE 2nd part runs backwards in relation to the medial wall of the middle ear.

The third part is directed vertically downwards behind the promontory.

The first bend at junction of the first and second part is sharp.

It lies over the anterosuperior part of the promontory , and is also called genu.

The geniculate ganglion of the nerve is called because it lies on the genu.

The second bend is gradual and lies between the promontory and the aditus to the mastoid antrum.

BRANCHES AND DISTRIBUTION

A. Within the facial canal 1.greater petrosal nerve 2.The nerve to the stapedius 3.The chorda tympani B. At its exit from the stylomastoid foramen . 1. Posterior auricular 2. Digastric 3. stylomastoid C. Terminal branches within the partoid gland 1. Temporal 2. Zygomatic 3. Buccal 4. Marginal mandibular 5. Cervical D. COMMUNICATING BRANCHES WITH ADJACENT CRANIAL AND

SPINAL NERVE

1.THE NERVE TO STAPEDIUS It arises opposite the pyramid of middle ear. It supplies stapedius muscle. Paralysis of this muscle cause hyperacusis.

2. CHORDA TYMPANI Arises in vertical part of facial canal.,about 6mm

above the stylomastoid foramen. It enters from middle ear and runs forward in close

relation to the tympanic membrane . It leaves middle ear by passing through

petrotympanic fissure. In infratemporal fossa it joins lingual nerve.

3. POSTERIOR AURICULAR NERVE Arises just below the stylomastoid

foramen. It ascends between mastoid process

and external acoustic meatus. It supplies : 1. Auricularis posterior 2. 0ccipitalis 3. Intrinsic muscle on the

back of auricle.

4.DIGASTRIC BRANCH. Supplies the posterior belly of the

digastric.

5.STYLOHYOID BRANCH. Arises with the digastric branch Supplies the stylohyoid muscle.

6. TEMPORAL BRANCHES Supplies : 1. auricularis anterior 2. auricularis posterior 3. intrinsic muscles on the

lateral side of the ear 4.frontalis 5. orbicularis oculi 6. corrugator supercilli

7.ZYGOMATIC BRANCHES It runs across the zygomatic bone and supply the orbicularis oculi.

BUCCAL BRANCHES : upper buccal branch lower buccal branch upper branch runs above parotid duct. lower branch runs below parotid duct.

THE MARGINAL MANDIBULAR BRANCH Runs below the angle of mandible deep to platysma. It supplies muscle of lower lip and chin.

8.CERVICAL BRANCH. Emerges from the apex of parotid

gland Runs downwards and forwards in neck

to supply platysma.

The ganglia associated with facial nerve are:

1. The geniculate ganglion . 2. The submandibular ganglion 3. The pterygopalatine ganglion

Healthcare

FACIAL & TRIGEMINAL NERVE 2