INNERVATION OF THE OROFACIAL REGION

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Are set 12 nerves that arise directly from the brain

Relay the information between the brain and the parts of the body

Primarily to and from regions of the head and neck

Cranial nerves are in contrast to spinal nerves which emerge from segments of spinal cord.

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I N. olfactory

II N. optical

III N. oculomotor

IV N. trochlear

V N. trigeminal

VI N. abducens

VII N. facial

VIII N.vestibulocochlear

IX N. glossopharyngeal

X N. vagus

XI N. accessory

XII N. hypoglossal

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Nerves of the Oro-facial region

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Nerves of the Oro-facial region

There are four cranial nerves that supply the oral cavity and its surrounding structures. They are

The trigeminal nerve

The facial nerve

The glosopharyngeal nerve

The Hypoglossal nerve

Its the largest of the cranial nerves, gives sensory supply to the face, the greater part of the scalp, the teeth, the oral and the nasal cavities.

It gives motor supply to muscles of mastication

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Trigerminal nerve has three major branches

The ophthalmic (V1)

Maxillary (V2)

Mandibular (V3)

The ophthalmic and maxillary nerves are purely sensory. The mandibular nerve has both sensory and motor functions.

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Trigeminal nerve cont..

The three branches converge on the trigeminal ganglion (also called the semilunar ganglion or gasserian ganglion)

This contains the cell bodies of incoming sensory nerve fibers.

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Branches of trigeminal nerve leave the skull through the following

Nerve Branch

Opening

Ophthalmic

Superior Orbital Fissure

Maxillary

Foramen Rotundum

Mandibular

Foramen Ovale

The areas of cutaneous distribution (dermatomes) of the three branches of the trigeminal nerve have sharp borders with relatively little overlap (unlike dermatomes in the rest of the body, which show considerable overlap).

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Is the smallest of the three trigeminal nerve divisions

Totally sensory and arises from the antero-medial part of the trigeminal ganglion. Passing forwards, just before entering orbit through the superior orbital fissure

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Passing forwards, just before entering orbit through the superior orbital fissure

it divided into three branches namely

The lacrimal nerve,

The frontal nerve

And the nasocilliary nerve

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Provides sensory innervations to the following structures

Forehead and scalp

Frontal,ethmoid and sphenoid sinueses

Upper eyelid and its conjuctiva

Dorsum of the nose

Lacrimal gland

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The Maxillary nerve is entirely sensory and leave the skull through foramen Rotundum in the greater wing of Sphenoid bone to enter the pterygopalatine fossae to enter the orbit through inferior orbital fissure

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In this pterygopalatine fossae the nerve splint into three major branches which are

The pterygopalatine nerve

The infraorbotal nerve

Zygomatic nerve

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Sub branches of maxillary nerve

The pterygopalatine nerve

The nerve gives the following branches

Superior posterior nasal nerve- supply the posterior part of the upper and middle nasal conchae also gives branches called nasopalatine nerve- through the incisive canal to supply palatine mucosal of the oral cavity

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Cont…

The palatine nerve- which divided into

Greater palatine nerve enters the oral cavity through major palatine foramen. Supply the mucosa of the hard palate.

Lesser palatine nerve that enter oral cavity through lesser palatine foramen to supply the palatine tonsil and soft palate.

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Cont…

The infraorbital nerve

The nerve gives out the following branches

Posterior superior alveolar nerve which Supplies the mucous membrane of the maxillary sinus, Some branches goes to join superior dental plexus that supply the molar teeth and gum in that region

Middle superior alveolar nerve join the superior dental plexus and supply upper premolar and gum in that region

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Cont…

Anterior superior alveolar nerve. The nerve form the anterior part of the superior dental plexus, from this plexus emerge small branches that supply the canine and incisor teeth also the gum in this region

The terminal branches of infraorbital nerve comes out through infraorbital foramen to supply the skin of lower eyelid, skin on the side of the nose, skin and mucous membrane of the upper lip

Zygomatic branch

Devides into zygomaticotemporal and zygomaticofacial nerves.

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Gives sensory supply to

Cheek

Inferior eyelid

Ala of the nose

Upper lip

Soft and hard palate

Upper teeth and gums

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Is a mixed nerve consisting of a large sensory part and a motor part.

Supply the dura mater in the brain and the muscle of mastication, other branches supply also to the mandibular teeth, parotid glands, tongue and skin and fascia of the temple and scalp. Is the largest branch of trigeminal nerve divisions. All mandibular teeth are supplied by the inferior alveolar nerve the branch of trigeminal nerve

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Has 9 branches which include

Inferior alveolar nerve – this nerve accompanies the inferior alveolar artery in mandibular foramen thro’ mandibular canal and exit thro’ mental foramen.

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Lingual nerve: runs parallel with I.A.V, to the lateral aspect of the tongue, easy during surgeries of the mouth floor

Auriculotemporal nerve: supply the parotid gland

Buccal nerve: gives bucinator branches

Lateral pterygoid nerve

Temporal nerve: temporal muscle.

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Medial pterygoid

Recurrent meningeal nerve: The nerve enters the skull via the foramen spinosum with the meningeal artery to supply the meninges.

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5 minutes

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This is the seventh (VII) of twelve paired cranial nerves.

It emerges from the brainstem between the pons and the medulla,

The nerve travels from the porn through the facial canal in the temporal bone and exits the skull at the stylomastoids foramen

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The branches of the facial nerve are divided into two

Intra cranial

Extra cranial branches

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Greater petrosal nerve: provides innervations to several glands includes nasal gland, lacrimal gland and pharyngeal gland.

Also provide innervations to sphenoid, frontal, maxillary, ethmoid sinuses and nasal cavity.

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Chorda tympani: to submandibular gland, sublingual gland and special sensory taste fibres for the anterior 2/3 of the tongue.

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Branches at distal to stylomastoid foramen

Posterior auricular nerve- movement of some scalp muscle and around the ear.

Branches to posterior belly of digastric muscle and stylohyoid muscles

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In parotid gland

Temporal branch- frontalis, orbicularis oculi

Zygomatic branch- orbicularis oculi

Buccal branch- bucinator muscles( cheek), Orbicularis oris( upper lip), zygomaticus muscles

Marginal mandibular branch- orbicularis oris{lower lip} and chin muscles

Cervical branch- platysma muscle.

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Controls the muscles of facial expression,taste to the anterior two-thirds of the tongue.

Provides innervations to several glands includes nasal gland, lacrimal gland and pharyngeal gland.

Provides motor innervation to stapedious muscles in middle ear.

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Cranial nerve number nine, mixed motor and sensory nerve.

In its passage through the jugular foramen passes between internal jugular vein and internal carotid artery, lateral and anterior to vagus and accessory nerve.

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Stylopharyngeal

Tonsillar

Carotid sinus nerve

Branches of posterior third of the tongue

Lingual branches

tympanic

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contributes to pharyngeal plexus

Special sensory branch, supply posterior third of the tongue

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Is the twelfth cranial nerve which solely motor function.

Arises from the hypoglossal nucleus in the medulla as a number of small rootlets

There are pair of hypoglossal nerve, which exit through the hypoglossal canal

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The nerve passes down the neck and eventually passes up again over the tongue muscles it supplies into the tongue.

Innervates the extrinsic and intrinsic muscles of the tongue.

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Involved in controlling tongue movement required for speech and swallowing, and side to side movement.

Innervates the extrinsic muscles (genioglossus, hyoglossus,styloglossus, geniohyoid except palatoglossus which innervated by vagus nerve.) and intrinsic muscles of the tongue

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