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Trigeminal Nerve Anatomy

Author: Ted L Tewfik, MD; Chief Editor: Arlen D Meyers, MD, MBA more...

Updated: Jun 19, 2013

Gross Anatomy

The trigeminal nerveis the largest and most complex of the 12 cranial nerves (CNs). It supplies sensations to the

face, mucous membranes, and other structures of the head. It is the motor nerve for the muscles of mastication

and contains proprioceptive fibers. It exits the brain by a large sensory root and a smaller motor root coming out of

the pons at its junction with the middle cerebral peduncle. It passes laterally to join the gasserian (semilunar)

ganglion in the Meckel cave. (See the image below.)

Schematicrepresentation of the trigeminal nerve w ith its central connections.

Nuclei

The sensory nucleus, located in the pons, is quiteextensive. It receives ordinary sensations from the main 3

branches of the trigeminal. The ophthalmic division is in the lower part of the nucleus, and the mandibular branch

is in the upper part. The large rostral head is the main sensory nucleus. The caudal tapered part is the spinal tract,

which is continuous with substantia gelatinosa of Rolando in the spinal cord. The spinal tract is the sensory

nucleus, primarily for pain and temperature. The main sensory nucleus serves mostly for discrimination sense. [1, 2,

3, 4, 5]

The motor nucleus is ventromedial to the sensory nucleus. It lies near the lateral angle of the fourth ventricle in the

rostral part of the pons. The mesencephalic nucleus is in the midbrain and receives proprioceptive fibers from all

muscles of mastication.

Connections

The main sensory nucleus receives its afferents (as the sensory root) from the semilunar ganglion through the

lateral part of the pons ventral surface. Its axons cross to the other side, ascending to the thalamic nuclei to relay

in the postcentral cerebral cortex. The descending sensory fibers from the semilunar ganglion course through the

pons and medulla in the spinal tract of CN V to end in the nuclei of this tract (as far as the second cervical

segment). (See tables 1 and 2, below.)

The axons of these nuclei cross to the opposite side, ascending in the spinothalamic tract, to relay in the thalamic

nuclei; from there, they end in the cerebral cortex. The sensory nucleus of CN V is connected to other motor

nuclei of the pons and medulla. In addition, the descending sensory spinal tract receives somatic sensory fibers

from CNs VII, IX, and X.

The proprioceptive fibers of CN V arise from the muscles of mastication and the ext raocular muscles. They

terminate in the mesencephalic nucleus. This nucleus has connections to the motor nucleus of CN V.

The motor nucleus of CN V receives cortical fibers for voluntary control of the muscles of mastication. These fibersare mostly crossed. It also receives input from the mesencephalic and sensory nuclei. The axons emerge anterior

to the sensory root from the lateral surface of the pons. This motor root joins the semilunar ganglion together with

the sensory root.

The semilunar (gasserian or trigeminal) ganglion is the great sensory ganglion of CN V. It contains the sensory cell

bodies of the 3 branches of the trigeminal nerve (the ophthalmic, mandibular, and maxillary divisions). The

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

The gasserian ganglion lies in a depression on the petrous apex, within a dural fold called the Meckel cave. The

sensory roots of the 3 branches of CN V are received anteriorly. They then pass from the posterior aspect of the

ganglion to the pons. The motor root passes under the ganglion to join the sensory division of the mandibular nerve

and exits the skull through foramen ovale. The carotid plexus contributes sympathetic fibers to the gasserian

ganglion.

Table 1. Summary of the Components, Function, Central Connections, Cell Bodies, and Peripheral Distribution of

CN V.(Open Table in a new window)

Components Function Centralconnection

Cell bodies Peripheral distribution

Afferent

general

somatic

General

sensibility

Sensory

nucleus V

Gasserian

ganglion

Sensory branches of the ophthalmic, maxillary, and

mandibular nerves to skin, mucous membranes of

the face and head

Efferent

special

visceral

Mastication Motor nucleus

V

Motor nucleus

V

Branches to temporalis, masseter, pterygoids,

mylohyoid, tensor tympani, and palati

Afferent

proprioceptive

Muscular

sensibility

Mesencephalic

nucleus V

Mesencephalic

nucleus V

Sensory endings in muscles of mastication

Table 2. Summary of the Types of Fibers, Function, and Pathways of the Trigeminal Nerve.(Open Table in a new

window)

Type Function Pathway

Branchial

motor

Motor to muscles of

mastication

CN V innervates the muscles of mastication, mylohyoid, tensor tympani, tensor

veli palate, anterior belly of digastric

General

sensory

Sensory from

surface of head and

neck, sinuses,

meninges and TM

The Gasserian ganglion receives the ophthalmic, maxillary and mandibular

divisions of CN V and sympathetic fibers from the carotid plexus and sends

branches to the dura. The four accessory ganglia are anatomically but not

functionally associated with CN V

Branches of the Trigeminal Nerve

The ophthalmic, maxillary, and mandibular branches of the trigeminal nerve leave the skull through 3 separate

foramina: the superior orbital fissure, the foramen rotundum, and the foramen ovale, respectively. (See the image

below.)

Diagram of the trigeminal nerve w ith its 3 main branches.

The ophthalmic nerve

The ophthalmic nerve is the first branch of the trigeminal nerve. It arises from the convex surface of the gasserian

ganglion, in the dura of the lateral wall of the cavernous venous sinus under CN IV and above the maxillary nerve,

as seen in the image below.

Diagram show ing the structures in the cavernous sinus.

The ophthalmic nerve carries sensory information from the scalp and forehead, the upper eyelid, the conjunctiva

and cornea of the eye, the nose (including the tip of the nose, except alae nasi), the nasal mucosa, the frontal
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sinuses, and parts of the meninges (the dura and blood vessels).

The ophthalmic nerve receives sympathetic filaments from the cavernous s inus and communicating branches from

CN III and IV. Just before it exits the skull through the superior orbital fissure, i t gives off a dural branch, and then

divides into 3 branches: the frontal, lacrimal, and nasociliary. (See the image below.)

Diagram of the f irst branch (ophthalmic) of the trigeminal nerve w ith its branches.

Frontal nerve

This is the largest branch of the ophthalmic nerve (see Table 3, below). It passes in the lateral part of the superior

orbital fissure, below the lacrimal nerve and above CN IV, between the periorbita and levator palpebrae superioris. It

divides in the middle of the orbitinto the supraorbital (larger branch) and supratrochlear nerves.

Table 3. The Ophthalmic Nerve Branches and Distribution. (Open Table in a new window)

Nerve Branches DistributionFrontal nerve Supraorbital nerve

Supratrochlear nerve

Upper lid, frontalis muscle, scalp

Conjunctiva, upper lid, forehead

Lacrimal nerve Receives branch from the zygomatic nerve of the

maxillary

Lacrimal gland, conjunctiva, upper lid

Nasociliary

nerve

Anterior ethmoid nerve

Branches to ciliary ganglion

Posterior ethmoid nerve

2-3 long ciliary nerves

Frontal, anterior, ethmoid sinuses

Anterior septum, nasal wall

Cornea, iris, ciliary body

Posterior ethmoid sphenoid

sinuses

Eye

The supraorbital nerve exits the skull through the supraorbital notch (or foramen). It supplies the upper lid and then

turns superiorly under the frontalis muscle to supply the scalp (via lateral and medial branches) as far posteriorly

as the lambdoid suture.

The supratrochlear nerve exits the medial orbit and gives branches to the conjunctiva and the skin of the upper lid,

as well as to the lower and medial parts of the forehead. The branch to the frontal sinus pierces it in the

supraorbital notch to supply the frontal sinus mucosa.

Lacrimal nerve

The lacrimal nerve arises in the narrow, lateral part of the superior orbital fissure and courses between the lateral

rectus and the periorbita. It supplies the lacrimal gland, conjunctiva, and upper lid. In the orbit, it receives a

communication from the zygomatic branch of the maxillary nerve. This represents postganglionic parasympathetic

secretory fibers from the sphenopalatine ganglion to the lacrimal gland. The preganglionic fibers reach the ganglion

via the greater petrosal and vidian nerves from CN VII.
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Nasociliary nerve

After passing through the superior orbital fissure, the nasociliary nerve gives origin to the anterior ethmoid nerve

that passes to the anterior ethmoid foramen lateral to the crista galli, to supply the fontal and anterior ethmoid

sinuses. After dropping in the nose, it supplies the anterior part of the septum and lateral nasal wall. After

emerging from the nose as the external nasal nerve, it supplies the skin of the nasal tip.

The nasociliary nerve gives a branch to the ciliary ganglion that passes without synapsing to the cornea, iris, and

ciliary body. The posterior ethmoid nerves are given off before the anterior ethmoid and supply the posterior

ethmoid and sphenoid sinuses. The nasociliary nerve gives off 2-3 long ciliary nerves that enter the globe with the

short ciliary nerves of the ciliary ganglion.

Maxillary nerve

The maxil lary nerve carries sensory information from the lower eyelid and cheek, the nares and upper lip, the upper

teeth and gums, the nasal mucosa, the palate and roof of the pharynx, the maxillary, ethmoid and sphenoid

sinuses, and parts of the meninges. (See the image below.) The maxillary nerve is divided into 3 branches: the

zygomatic , pterygopalatine (or sphenopalatine), and posterior superior alveolar nerves.

Diagram of the second branch (maxillary) of the trigeminal nerve w ith its branches.

As it leaves the semilunar ganglion, the maxillary nerve passes through the dura of the lateral wall of the cavernous

sinus. It exits the skull via the foramen rotundum and crosses the pterygopalatine fossa to enter the orbit through

the inferior orbital fissure, where it becomes the infraorbital nerve. Before entering the foramen, it gives off a dural

branch (middle meningeal nerve). The zygomatic, pterygopalatine (or sphenopalatine) and posterior superior

alveolar branches are given off in the pterygopalatine fossa.

The zygomatic branch divides into the zygomaticotemporal and zygomaticofacial nerves.

In the lateral wall of the orbit, it gives off a branch to the lacrimal nerve, which carries postganglionic fibers from the

sphenopalatine ganglion for lacrimation. The zygomaticofacial is inferiorly situated and supplies the skin of the

cheek.

The pterygopalatine (or sphenopalatine) nerves are 2 nerves that unite the sphenopalatine ganglion to the maxillary

nerve. They transmit afferent sensations from the nose, palate, and pharynx. They also carry parasympathetic

fibers to the lacrimal nerve that go to the lacrimal gland. These preganglionic fibers are derived from CN VII via the

greater petrosal and vidian nerves. The other branches of the sphenopalatine nerves and their distribution are

summarized in Table 4, below.

Table 4. The Maxillary Nerve Branches and Distribution. (Open Table in a new window)

Nerve Branches Distribution

Middle meningeal

nerve

Dura

Zygomatic nerve Zygomatico-temporal

Zygomatico-facial

Lacrimal gland

Forehead

Cheek

Pterygopalatine

nerve

2 branches unite sphenopalatine

ganglion and maxillary nerve

Greater palatine nerve

Posterior superior nasal nerve

Nasal cavity, pharynx, palate

Soft and hard palate

Superior, middle turbinate, septum
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Pharyngeal

Nasopharynx

Posterior superior

alveolar nerve

Middle, anterior, superior alveolar, and

nasal nerves

Gums, posterior cheek, teeth (canine,

incisors, premolar), nasal floor

The posterior superior alveolar nerves are usually 2 in number. They supply the mucosa of the posterior cheek and

gingiva; Table 4 has their distribution and the other small branches.

The mandibular nerve

The mandibular nerve is the largest branch of the t rigeminal nerve, as seen in the image below. It has mixed

sensory and motor fibers (see Table 5, below).

Diagram of the third branch (mandibular) of the trigeminal nerve w ith its branches.

The mandibular nerve carries sensory information from the lower lip, the lower teeth, gums, the chin and jaw

(except the angle of the mandible, which is supplied by C2-C3), parts of the external ear, and parts of the

meninges. The mandibular nerve carries touch/position and pain/temperature sensations from the mouth. It does

not carry taste sensation (the chorda tympani is responsible for taste), but one of its branches, the lingual nerve,

carries multiple types of nerve fibers that do not originate in the mandibular nerve.

Motor branches of the trigeminal nerve are distributed in the mandibular nerve. These fibers originate in the motor

nucleus of the fifth nerve, which is located near the main trigeminal nucleus in the pons. (See the image below.)

Diagram of the sensory and motor supply of the face.

The mandibular nerve has the following 9 branches:

Recurrent meningeal nerve - This nerve enters the skull via the foramen spinosum with the meningeal artery

Medial pterygoid nerve - After passing through the otic ganglion without synapsing, this nerve supplies the

medial pterygoid, tensor veli palatini, and tensor tympani muscles

Masseteric nerve - This nerve passes through the mandibular notch to innervate the masseter muscle and

temporomandibular joint (TMJ)

Deep temporal nerves - The anterior and posterior branches supply the temporal muscle

Lateral pterygoid nerve

Buccal nerve - This nerve divides into the temporal and buccinator branches

Auriculotemporal nerve - This nerve begins as 2 roots that encircle the middle meningeal artery, then forms

a single trunk medial to the neck of the mandible; it emerges superficially between the ear and the

mandibular condyle deep to the parotid gland and ends in 2 superficial temporal branches (for autonomic

supply to the parotid gland, see below)

Lingual nerve - This nerve runs parallel to the inferior alveolar nerve, is joined by the chorda tympani nerve ofthe facial nerve (CN VII) near the internal maxillary artery, courses forward between the hyoglossus muscle

and the deep part of the submandibular gland, and, as it passes forward, crosses the submandibular

(Wharton) duct; the lingual nerve could be injured in this location during surgery on the floor of mouthor

during excision of the submandibular gland (for more details regarding the nerve supply of the salivary

glands, see below)

Inferior alveolar nerve - This nerve accompanies the inferior alveolar artery in the mandibular foramen and
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courses into the mandibular canal to exit through the mental foramen; the different branches are listed in

Table 5, below

Table 5. Mandibular Nerve Branches and Distribution.(Open Table in a new window)

Nerve Branches Distribution

Recurrent

meningeal

Dura

Medial pterygoid Medial pterygoid, tensor veli palatini, tensor tympani

muscles

Masseteric Masseter muscle, temporomandibular joint

Deep temporal

(x2)

Temporalis muscle

Lateral pterygoid Lateral pterygoid muscle

Buccal Temporal nerve (upper)

Buccinator nerve (lower)

Skin of cheek, mucous membrane of mouth, and gingiva

Auriculotemporal Communication with facial

nerve, and otic ganglion,

Articular nerve

Parotid gland

Parasympathetic and sympathetic supply to the parotid

gland, after relay in the otic ganglion

8) Lingual Communicates with CN VII via

chorda tympani

Taste sensations to the anterior third of tongue

9) Inferior

alveolar

Mylohyoid

Dental

Incisive

Mental

Mylohyoid, anterior, belly of digastric, molars, premolars,

canine, incisors lower lip, and chin

Microscopic Anatomy

Sensory nerve endings that respond to stimuli and convert them to nervous energy toward the central nervous

system are called receptors or central transducers. Sensory receptors are classified into the following 3 main

groups: exteroreceptors, interoreceptors, and proprioceptors.[6, 7, 8]

Exteroreceptors

These are stimulated by the external environment. Examples of these types of receptors include the following:

Merkel corpuscles - Located in submucosa of the tongue and oral cavity (see the image below)


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(2) Merkel disc ending. Horseradish peroxidase (HRP) has diffused into the hair shaft and surrounded the disc-shaped nerve

terminal. Key: Merkel cell (M), nerve terminal (nt). Inset: Incorporated HRP in the nerve terminal, x8, 750. Inset: x32, 4003 (3 and

4). Detail of a Merkel disc ending. HRP is seen in various vacuoles in the nerve terminal. x 39,000.

Meissner corpuscles - Tactile receptors in the skin

Ruffini corpuscles - Pressure and warmth receptors

Krause corpuscles or end bulbs - Cold receptors

Free nerve endings - Perceive superficial pain and tact ile sensations

Interoreceptors

These are located in and transmit sensations from body cavities. Most of the sensations for these structures deal

with body functions and are below the conscious level. Examples include the following:

Pacinian corpuscles - Detect pressure sense

Free nerve endings - Perceive visceral or other sensations

Proprioceptors

The sensations associated with proprioceptors are also below conscious level; examples include the following:

Muscle spindles - Respond to passive stretch of the muscle

Golgi tendon organs - Located in tendons and respond to muscle tension (contraction and stretching)

Pacinian corpuscles - Respond to pressure

Proprioceptors - Respond to periodontal sensation

Sensory nerve endings - Perceive deep somatic pain

Natural VariantsDifferent anatomic variations have been described regarding the trigeminal nerve, its branches, and its

subdivisions. Examples include the very rare occurrence of unilateral trigeminal nerve hypoplasia, in which no

corneal sensitivity exists on the affected side and facial sensitivity is reduced in all branches of the trigeminal

nerve. Anomalies may coexist also in association with craniofacial anomalies, such as hypoplasia of the

trigeminal nerve in Goldenhar syndrome (oculo-auriculo-vertebral dysplasia). A few other examples affecting the

different divisions are described below. [9, 10, 11, 12, 13, 14]

Frontal nerve

A variation has been reported in which the frontal nerve divides at a variable point before leaving the orbit to form

the supratrochlear and supraorbital branches. In such cases, the supraorbital branch passes through the

supraorbital foramen, through which the undivided nerve ordinarily passes. When the foramen is absent, it may

have a special groove, the frontal notch (Henle notch).

The frontal nerve runs, at first forward, in a sagittal direction. In approximately 90% of subjects, it divides during its

course within the orbit, but in 10% of persons it remains undivided. It divides into the larger lateral supraorbital

nerve and smaller supratrochlear nerve, which runs medially. In 60% of subjects, the supraorbital nerve does not

divide, but in 30% it divides into the medial branch, which leaves the orbit through the frontal foramen or notch, and

the lateral branch passes out through the frontal foramen. In about 90% of subjects, the supratrochlear nerve runs

along the surface of the superior oblique muscle. In 4% of subjects, 2 supratrochlear nerves exist.

Ethmoidal nerve

This nerve may be limited to the nasal cavity. It may also traverse the posterior ethmoidal foramen to gain entrance

to the cranial cavity.

Lacrimal nerve

This nerve may appear to be derived from the trochlear nerve. However, the probable source in such cases is the

ophthalmic nerve, through its communicating branch to the trochlear nerve (CN IV) in the cavernous sinus.

The lacrimal nerve may be small at its origin, increasing in size later in its course by the addition of fibers derived

from the temporal branch of the maxillary division of the trigeminal nerve. The lacrimal nerve may be absent and

replaced by the temporal branch of the maxillary division of the trigeminal nerve.
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The lacrimal nerve occasionally gives rise to a ciliary nerve, or it receives a branch from a long ciliary nerve of the

ciliary ganglion or a branch from the ganglion directly. It may receive accessory roots from the supraorbital or

nasociliary nerves.

The bifurcation of the lacrimal into its terminal branches may occur on the posterior wall of the orbital cavity. A

branch of the lacrimal has been noted to pierce the sclera.

The lacrimal nerve may exchange fibers with the c iliary ganglion.

Nasociliary (nasal) nerve

Several variations in the branches of this nerve have been reported. The nasociliary nerve may send branches tothe superior rectus, medial rectus, and levator palpebral superioris muscles. Branches emanating from a small

ganglion connected to the nasal nerve have been followed to the oculomotor (CN III) and abducens (CN VI) nerves.

The infratrochlear branch of the nasal (nasocil iary) nerve may be missing, in which case the areas normally

supplied by this branch (skin of the upper eyelid, root of nose, conjunctiva, lacrimal sac) receive their supply from

the supratrochlear branch of the frontal nerve.

Branches of the nasal nerve have been described passing to the frontal, ethmoid, and sphenoid sinuses. The

branches to the frontal and anterior ethmoid sinuses arise in the anterior ethmoid foramen; branches to the

sphenoid and posterior ethmoid sinuses arise in the posterior ethmoid foramen. The branches to the sphenoid

sinuses are known as sphenoid branches, whereas the branches to the posterior ethmoid sinuses are known as

sphenoethmoid or posterior ethmoid branches. An anastomosis between the nasal and lacrimal nerves has been

reported.

Maxillary division (V2)

The maxillary nerve may split into 2 trunks, each entering the skull through a separate foramen

Zygomatic nerve

The following variations have been reported in this nerve or its 2 branches (the temporal or facial or malar). The

nerve may pass through the zygomatic bone before it divides into 2 branches, or the 2 branches may pass

separately through foramina in the zygomatic bone instead of passing through a common foramen

(sphenozygomatic foramen). The temporal branch in some cases passes through the sphenomaxillary fissure into

the temporal fossa.

Either branch of the zygomatic may be absent or smaller than normal, in which case the other branch

compensates by carrying the additional nerve fibers. The area usually supplied by the zygomatic branch (skin of

the zygomatic region) may be supplied instead by the infraorbital nerve. The area usually supplied by the temporalbranch (sk in of the anterior temporal region) may be supplied solely or additionally by the lacrimal nerve.

Posterior superior alveolar nerve

In the absence of the buccal nerve, the posterior superior alveolar nerve distributes branches to the areas normally

supplied by this nerve (mucous membrane and skin of the cheek).

Inferior alveolar nerve

The inferior alveolar nerve may form a single trunk with the lingual nerve, extending as far as the mandibular

foramen. The inferior alveolar nerve is sometimes perforated by the internal (medial) maxillary artery. It may have

accessory roots from other divisions of the mandibular nerve. In some cases, the mylohyoid branch of the inferior

alveolar gives rise to a branch that pierces the mylohyoid muscle and joins the lingual nerve.

Branches have been described arising from the mylohyoid branch and supplying the depressor anguli oris muscleand parts of the platysma (that are usually supplied by the facial nerve), the skin below the chin, and the

submandibular (submaxillary) gland (which is usually supplied by the facial nerve). The inferior alveolar may form

connections with the auriculotemporal nerve. In one case, the roots of the third lower molar tooth were found to be

surrounding the inferior alveolar nerve.

Auriculotemporal nerve

This nerve carries the otic ganglion, which is derived from glossopharyngeal neurons. The nerve usually arises by 2

roots from the posterior division of the mandibular nerve. The 2 roots usually surround the middle meningeal nerve

before joining to form a single trunk. A variation in this relationship has been described in which the middle

meningeal artery pierces the anterior root instead of passing between the 2 roots.

According to Baumel et al, the auriculotemporal nerve is commonly misrepresented in illustrations and textbooks.[11]

Their 85 dissections of the nerve demonstrated that the roots of the " typical" auriculotemporal nerve do notform a tight buttonhole around the middle meningeal artery. Instead, the roots outline an elongated, V-shaped

interval, with the roots widely separated from one another. At their junction, the roots form a short trunk that

immediately breaks up in line with the posterior border of the mandible into a spray of branches.

The superficial temporal ramus of the auriculotemporal nerve should not be considered as the main continuation of

the nerve but merely as its largest branch. A substantial portion of the nerve makes up its 2 communicating rami


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with the facial nerve; these are the strongest and most consistent of the many peripheral communications between

trigeminal and facial nerves. Common variations in configuration, branching, and relationships of the nerve are

discussed in the report by Baumel et al.

Lingual nerve

A minute sublingual ganglion has been described arising from the lingual nerve or submandibular ganglion (a

ganglion of the facial nerve carried by the lingual nerve), supplying the sublingual gland. This nerve may pierce the

lateral pterygoid muscle rather than pass between the 2 pterygoid muscles. It occasionally provides motor

branches to the medial and lateral pterygoids and to the palatoglossus muscle.

Relationships to superior petrosal sinus

Vascular relationships are important during intracranial approaches to the skull base. The relationship between the

superior petrosal s inus (SPS) and the opening of the Meckel cave (MC) was studied by Tubbs et al (2013), who

found (through cadaver dissections) 3 types of relationships, as follows[15] :

SPSs traveled superior to the opening of the MC in 68%

SPSs traveled inferior to the opening of the MC in 18%

SPSs traveled around to the opening of the MC in 16% of cadavers

In the third variety, a venous ring was formed around the proximal trigeminal nerve. In these cases, the opening

was narrowed on sides found to have an SPS that encircled this region. No statistically significant differences were

noted between persons of different sex or age or in regard to the side of the head. They concluded that some

individuals may retain the early embryonic position of their SPS in relation to the fifth nerve.

Pathophysiological Variants

Trigeminal neuralgia and neuropathy are thought to arise from damage or pressure on the trigeminal nerve,

whereas temporomandibular disorders (TMDs) result primarily from peripheral nociceptor act ivation. Wilcox et al

(2013) used T1-weighted magnetic resonance images to assess the volume and microstructure of the trigeminal

nerve in these 3 conditions.[16] They found that trigeminal neuralgia patients displayed a 47% decrease in nerve

volume, but no change in diffusion-tensor images (DTIs). On the other hand, trigeminal neuropathy patients

displayed a 40% increase in nerve volume but no changes in DTI values. In contrast, TMD subjects displayed no

change in volume or DTIs. This publication revealed that orofacial pain conditions are associated with changes in

nerve volume, whereas nonneuropathic pain is not associated with any volume change.

Regarding trigeminal neuralgia(also known as tic douloureux), the differential diagnoses is as follows (also, see

Table 6 and text below)[6, 17, 18, 19, 20, 21] :

Cluster headache (CH): The pain and symptoms of CH result from activation of the trigeminal

parasympathetic reflex, mediated through the sphenopalatine ganglion (SPG). Schoenen et al (2012)

investigated the safety and efficacy of on-demand SPG stimulation for chronic CH (CCH).[22]A mult icenter

study of an implantable on-demand SPG neurostimulator was conducted in patients suffering from

refractory CCH. Most patients (81%) experienced transient, mild/moderate loss of sensation within distinct

maxillary nerve regions; 65% of events resolved within 3 months. Results showed that the on-demand SPG

stimulation using this neurostimulation system is an effective novel therapy for CCH, with dual beneficial

effects, acute pain relief and observed attack prevention, and has an acceptable safety profile compared

with similar surgical procedures.

Low-grade astrocytoma

Arteriovenous malformations

Brainstem gliomas

Meningioma

Cavernous sinus syndromesMigraine headache

Trigeminal neuropathy

Trigeminal neuritis

Chronic paroxysmal hemicrania

Migraine variants

Multiple sclerosis

Craniopharyngioma

Persistent idiopathic facial pain

Glioblastoma multiforme

Polyarteritis nodosa

Hemifacial spasm

Postherpetic neuralgia

Hydrocephalus

Subarachnoid hemorrhageAtypical facial pain

Ramsay Hunt syndrome

Glossopharyngeal neuralgia

Malignant and nonmalignant pain syndromes

Occipital neuralgia

Tic convulsif
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Cerebral aneurysms

Brainstem syndrome

Table 6. The Difference Between Atypical Facial Pain and Trigeminal Neuralgia. (Open Table in a new window)

Feature Trigeminal Neuralgia Atypical Facial Pain

Prevalence Rare Common

Main location Trigeminal area Face, neck, ear

Pain duration Seconds to 2 minutes Hours to days

Character Electric jerks, stabbing Throbbing, dull

Pain intensity Severe Mild to moderate

Provoking factors Light touch, washing, shaving, eating, talking Stress, cold

Associated symptoms None Sensory abnormalities

TN has a reported incidence of 5.9 cases in 100 000 women and 3.4 cases in 100 000 men in the United States.

The exact pathophysiology is still unclear, but demyelization leading to abnormal discharge in fibers of the

trigeminal nerve is a probable cause. In most cases, no structural lesion is detected, but in almost 15% of

patients, medical imaging methods like MRI, CT,or angiography can identify a vein or artery that compresses the

nerve, which results in focal demyelization. Sava et al (2012) investigated a case of TN using MRI and identified

compression of the nerve 9 mm after emerging the pons by the superior cerebellar artery. [23] In the article, they

reviewed MRI anatomy of the trigeminal nerve.

Marcus Gunn phenomenon

Marcus Gunn phenomenon(also known as Marcus-Gunn jaw-winking or trigemino-oculomotor synkineses) is an

autosomal-dominant condition with incomplete penetrance, in which nursing infants have rhythmic upward jerking

of their upper eyelid. This condition has been associated with amblyopia (in 54% of cases), anisometropia (26%),

and strabismus (56%).

Marcus Gunn phenomenon is an exaggeration of a very weak physiologic cocontraction that has been disinhibited

secondary to a congenital brainstem lesion. The stimulation of the trigeminal nerve by contraction of the pterygoid

muscles results in the excitation of the branch of the oculomotor nerve (CN III) that innervates the levator palpebrae

superioris ipsilaterally.

Inverse Marcus Gunn phenomenon orMarin-Amat syndrome

Marin-Amat syndrome or inverse Marcus Gunn phenomenon is a rare condition that causes the eyelid to fall upon

opening of the mouth. In this case, trigeminal innervation to the pterygoid muscles is associated with an inhibitionof the branch of the oculomotor nerve to the levator palpebrae superioris, as opposed to st imulation in Marcus

Gunn jaw-winking. Garcia Ron et al (2011) presented one acquired case, after the surgery of tuberculosus cervical

adenitis, and another congenital case. The syndrome is rare in children, with few reported cases. [24] The diagnosis

is clinical and does not require additional tests. EMG may be useful to demonstrate the synkinesis.

Tolosa-Hunt syndrome

Tolosa-Hunt syndrome(THS) is a painful ophthalmoplegia caused by nonspecific inflammation of the cavernous

sinus or superior orbital fissure. Ophthalmoparesis or disordered eye movements occur when CNs III, IV, and VI

are damaged by granulomatous inflammation. Pupillary dysfunction may be present and is related to injury to the

sympathetic fibers or oculomotor nerve. Trigeminal nerve involvement (primarily V1) may cause paresthesias of the

forehead.

Lateral medullary syndrome

This condition is also called Wallenberg syndrome or posterior inferior cerebellar artery (PICA) syndrome. The

PICA supplies the lower cerebellum, the lateral medulla, and the choroid plexus of the fourth ventricle. In lateral

medullary syndrome, the patient has dysphagia and/or difficulty speaking owing to 1 or more patches of infarction

caused by interrupted blood supply to parts of the brainstem. For features of lateral medullary syndrome, see

Table 7, below.

Table 7. Features of Lateral Medullary Syndrome. (Open Table in a new window)

Dysfunction Effects

Vestibular nucleus Vestibular system: vertigo, diplopia, nystagmus,

vomiting

Inferior cerebellar peduncle Ipsilateral cerebellar signs, including ataxia

Central tegmental tract Palatal myoclonus

Lateral spinothalamic tract Contralateral deficits in pain and temperature

sensation from body

Spinal trigeminal nucleus Ipsilateral loss of touch pain and temperature

sensation from face
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Nucleus ambiguus (which affects vagus X and

glossopharyngeal nerves IX)

Dysphagia, hoarseness, diminished gag reflex

Descending sympathetic fibers Ipsilateral Horner syndrome

Parasympathetic Ganglia

Four small parasympathetic (accessory) ganglia are associated anatomically (but not functionally) with the

branches of the trigeminal nerve.[2, 4] They are as follows:

Ciliary ganglion

Sphenopalatine (or pterygopalatine) ganglionOtic ganglion

Submandibular ganglion

The ciliary ganglion is associated with the ophthalmic nerve. It is the size of a pinhead and has the following 3

roots:

The parasympathetic root from the nerve to inferior oblique (CN III) from Edinger Westphal nucleus and

caudal central nucleus to supply the sphincter papillae and ciliary muscles

Sympathetic root from the nasociliary nerve to dilator papillae muscle of the eye

Sensory root from the nasociliary nerve to the cornea

The sphenopalatine ganglion is associated with the maxillary nerve. It receives its parasympathetic fibers from CN

VII (as seen in the image below). The otic and submandibular ganglia are associated with the mandibular nerve.

They receive parasympathetic fibers from CNs IX and VII, respectively.

Sphenopalatine ganglion and its connections. Parasympathetic fibers are dashed.

Autonomic supply to the salivary glands

Submandibular gland

Parasympathetic fibers arise from the superior salivary nucleus in the pons. Fibers pass through the facial nerve to

the chorda tympani and then to the lingual nerve. Synapsing occurs in the submandibular ganglion and from there

to the submandibular salivary gland. Sympathetic supply is from the plexus around the facial artery.

Parotid gland

Parasympathetic fibers arise from the inferior salivary nucleus in the medulla oblongata, pass through the

glossopharyngeal nerve (CN IX), and then travel through its tympanic branch to the tympanic plexus (Jacobson

nerve). They emerge from the middle ear through a hiatus on the anterior surface of the petrous temporal bone, as

the lesser superficial petrosal nerve. This nerve passes via the foramen ovale to the otic ganglion (which hangs

from the medial side of the mandibular nerve).

Relay occurs in the otic ganglion, and from there it is distributed to the parotid gland via the auriculotemporalnerve. Sympathetic fibers are from the superior cervical ganglion; they go to the plexus around the meningeal

artery and from there to the auriculotemporal nerve, which distributes them to the parotid salivary gland.

Contributor Information and DisclosuresAuthor

Ted L Tewfik, MD Professor, Department of Otolaryngology-Head and Neck Surgery, Director of Continuing

Medical Education of Otolaryngology; and Professor of Pediatric Surgery, McGill Faculty of Medicine, Senior

Staff Montreal Children's Hospital, Montreal General Hospital and Royal Victoria Hospital

Ted L Tewfik, MD is a member of the following medical societies:American Society of Pediatric Otolaryngology

and Canadian Society of Otolaryngology-Head & Neck Surgery

Disclosure: Nothing to disclose.

Chief Editor

Arlen D Meyers, MD, MBA Professor of Otolaryngology, Dentistry, and Engineering, University of Colorado

School of Medicine

Arlen D Meyers, MD, MBA is a member of the following medical societies: American Academy of Facial Plastic

and Reconstructive Surgery,American Academy of Otolaryngology-Head and Neck Surgery, andAmerican
http://www.headandneckcancer.org/http://www.headandneckcancer.org/http://www.entnet.org/http://www.facemd.org/index.asphttp://www.entcanada.org/http://www.aspo.us/http://refimgshow%289%29/


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Head and Neck Society

Disclosure: Axis Three Corporation Ownership interest Consulting; Medvoy Ownership interest Management

position; Cerescan Imaging Honoraria Consulting

References

1. Agur AMR, Dalley AE. The Cranial Nerves. In: Grant's Atlas of Anatomy. Baltimore: Williams & Wilkins;

2004.

2. Sooy CD, Boles R. Neuroanatomy for the Otolaryngologist Head and Neck Surgeon. In: Paparella MM,

and Shumrich DA. Otolaryngology: Basic Sciences and Related Principles. Philadelphia: WB Saunders;

1991.

3. Moore KL, Dalley AL. Clinically Oriented Anatomy. 4th. Philadelphia: Lippincott Williams & Wilkins; 1999.

4. Martin JH. Neuroanatomy Text and Atlas. 3rded. McGraw-Hill; 2003.

5. Ropper AH, Brown RH.Adam's and Victor's Principles of Neurology. 8th. McGraw-Hill; 2001.

6. Bell WE. Orofacial Pains: Differential Diagnosis. 2nd. Year Book Medical Publisher; 1979.

7. Miller MR. Pain: Morphological Aspects . In: Way EL (ed). New Concepts in Pain. Philadelphia: FA Davis

Co; 1967.

8. Persson LA, Kristensson K. Uptake of horseradish peroxidase in sensory nerve terminals of mouse

trigeminal nerve.Acta Neuropathol. May 15 1979;46(3):191-6. [Medline].

9. Wilson-Pauwels, L, Akesson EJ, Stewart PA. Cranial Nerves: Anatomy and Clinical Comments. BC

Decker Inc; 1998.

10. Tewfik TL, Teebi, AS, Der Kaloustian VM. Selected Syndromes and Conditions. In: Tewfik TL, Der

Kaloustian VM (eds). Congenital Anomalies of the Ear, Nose, and Throat. New York: Oxford University

Press; 1997.

11. Baumel JJ, Vanderheiden JP, McElenney JE. The auriculotemporal nerve of man.Am J Anat. Apr

1971;130(4):431-40. [Medline].

12. Bergman RA. Anatomy Atlases. Available at http://anatomyatlases.org .

13. Ries MW, Tetz MR, Egelhof T, Volcker HE. [Unilateral trigeminal nerve hypoplasia]. Klin Monbl

Augenheilk d. Jul 1997;211(1):60-4. [Medline].

14. Villanueva O, Atk inson DS, Lambert SR. Trigeminal nerve hypoplasia and aplasia in children with

goldenhar syndrome and corneal hypoesthesia. J AAPOS. Apr 2005;9(2):202-4. [Medline].

15. Tubbs RS, Mortazavi MM, Krishnamurthy S, Verma K, Griessenauer CJ, Cohen-Gadol AA. The

relationship between the superior petrosal sinus and the porus trigeminus: an anatomical study. J

Neurosurg. May 24 2013;[Medline].

16. Wilcox SL, Gustin SM, Eykman EN, Fowler G, Peck CC, Murray GM, et al. Trigeminal Nerve Anatomy in

Neuropathic and Nonneuropathic Orofacial Pain Patients. J Pain. May 16 2013;[Medline].

17. Trigeminal neuralgia. Medscape Reference. Available at http://emedicine.medscape.com/article/1145144-

diagnosis. Accessed March 2010.

18. Medcyclopaedia. Trigeminal Neuropathy. Available at

http://www.medcyclopaedia.com/library/topics/volume_vi_2/t/trigeminal_neuropathy.aspx. AccessedMarch 2010.

19. Cates CA, Tyers AG. Results of levator excision followed by fascia lata brow suspension in patients with

congenital and jaw-winking ptosis. Orbit. 2008;27(2):83-9. [Medline].

20. Yamada K, Hunter DG, Andrews C, Engle EC. A novel KIF21A mutation in a patient with congenital

fibrosis of the extraocular musc les and Marcus Gunn jaw-winking phenomenon.Arch Ophthalmol. Sep

2005;123(9):1254-9. [Medline].

21. Tolosa-Hunt Syndrome. Medscape Reference. Available at

http://emedicine.medscape.com/article/1146714-overview. Accessed March 2010.

22. Schoenen J, Jensen RH, Lantri-Minet M, Linez MJ, Gaul C, Goodman AM, et al. St imulation of the

sphenopalatine ganglion (SPG) for cluster headache treatment. Pathway CH-1: A randomized, sham-

controlled study. Cephalalgia. Jan 11 2013;[Medline].

23. Sava A, Furnica C, Petreus T, Chistol RO, Motoc AG. Trigeminal nerve: MRI anatomy and case

presentation of trigeminal neuralgia due to arterial compression. Rom J Morphol Embryol.

2012;53(4):1097-102. [Medline].

24. Garca Ron A, Jensen J, Garriga Braun C, Gmez E, Sierra J. [Marin-Amat and inverted Marcus-Gunn
http://www.headandneckcancer.org/http://reference.medscape.com/medline/abstract/23303040http://reference.medscape.com/medline/abstract/23314784http://emedicine.medscape.com/article/1146714-overviewhttp://reference.medscape.com/medline/abstract/16157808http://reference.medscape.com/medline/abstract/18415867http://www.medcyclopaedia.com/library/topics/volume_vi_2/t/trigeminal_neuropathy.aspxhttp://emedicine.medscape.com/article/1145144-diagnosishttp://reference.medscape.com/medline/abstract/23685183http://reference.medscape.com/medline/abstract/23706047http://reference.medscape.com/medline/abstract/15838455http://reference.medscape.com/medline/abstract/9340409http://anatomyatlases.org/http://reference.medscape.com/medline/abstract/5581228http://reference.medscape.com/medline/abstract/88862http://www.headandneckcancer.org/


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