CRANIAL
NERVES
1
Presenter : Shyam
Moderator : Dr. Parimala
No. of slides - 54
Contents
02
04
• INTRODUCTION
• TYPES OF NERVES
• CLASSIFICAION OF CRANIAL NERVES
• CRANIAL NERVES (1 – 12)
• CONCLUSION
• REFRENCES
2
INTRODUCTION
04
• Cranial nerves are those nerves which arises
from brain and brain stem rather than spinal
cord.
• Nerve arising from the spinal cord are called
peripheral nerves.
• There are 12 pairs of cranial nerves, and these
nerves exits skull through foramina.
3
02
04
I. Olfactory
II. Optic
III. Oculomotor
IV. Trochlear
V. Trigeminal
VI. Abducent
VII.Facial
VIII.Vestibulo-cochlear
IX. Glossopharyngeal
X. Vagus
XI. Accessory
XII.Hypoglossal
THE 12 CRANIAL NERVES
OH
OH
OH
TRY
TRY
AGAIN
FAILURE
VICTORY
GIVE
VALUE
AND
HAPPINESS
MNEMONIC
4
Types of Nerves
 Motor Nerves-
 Function: Transmit motor commands from the central nervous system (CNS) to muscles and
glands.
 Role: Enable movement and actions, including both voluntary (e.g., walking) and involuntary (e.g.,
reflexes) movements.
 Key Points:
• Efferent pathway: Carries signals away from the CNS.
• Activates skeletal, smooth, or cardiac muscles.
 Sensory Nerves-
 Function: Carry sensory information from the body’s periphery to the CNS.
 Role: Responsible for processing external stimuli such as touch, temperature, pain, and
proprioception.
 Key Points:
•Afferent pathway: Transmits signals to the CNS.
•Enables perception of the environment and body’s condition.
5
 Mixed Nerves-
 Function: Perform both sensory and motor functions.
 Role: Provide dual functionality: sensory input to the CNS and motor output to
muscles or glands.
 Key Points:
•Combine afferent (sensory) and efferent (motor) fibers.
•Essential for coordinated body functions.
6
CLASSIFICATION OF CRANIAL NERVES
SENSORY CRANIAL
NERVES
• OLFACTORY
• OPTIC
• VESTIBULOCOCHLEAR
MOTOR CRANIAL
NERVES
• OCCULOMOTOR
• TROCLEAR
• ABDUCENT
• ACCESSORY
• HYPOGLOSSAL
MIXED CRANIAL NERVES
• TRIGEMINAL
• FACIAL
• GLOSSOPHARYNGEAL
• VAGUS
7
CRANIAL NERVE I - OLFACTORY
• It is sensory nerve.
• Shortest cranial nerve
• Carries impulses for sense of smell.
• ORIGIN: Olfactory epithelium
• Axons Passes through the cribriform plate of the
ethmoid bone
• Synapse in the olfactory bulb.
• Lesions may cause:
 Anosmia: Loss of smell.
 Hyposmia: Reduced sense of smell.
8
CRANIAL NERVE II - OPTIC
• It is sensory nerve.
• It carry impulses for vision.
• ORIGIN: Back of eyeball/ retina of eye.
• Axons converge to form the optic nerve.
• Passes through the optic canal in the sphenoid bone.
• Forms the optic chiasma, where partial crossing of fibers
occurs.
• Continues as the optic tract to the lateral geniculate
body of the thalamus
• Relays visual information to the occipital lobe (visual
cortex).
• Lesions may cause:-
 Blindness (complete optic nerve damage)
 Visual field defects (e.g., hemianopia)
9
CRANIAL NERVE III – OCULOMOTOR
• It is Motor nerve
• Function: Eye movement and pupil constriction
• ORIGIN: Oculomotor nucleus in the midbrain.
• Passes through the cavernous sinus
• Exits skull via the superior orbital fissure
• Supplies to all extraocular muscles except superior
oblique and lateral rectus.
(SO4, LR6, AO3)
• Lesions may cause:
• Ptosis: Drooping eyelid
• Diplopia: Double vision
• Mydriasis: Dilated pupil
• Eye deviation: "Down and out" position due to
unopposed action of lateral rectus and superior
oblique
10
CRANIAL NERVE IV- TROCHLEAR
• It is motor nerve.
• It has longest intracranial course, but also the
thinnest.
• Function: Depression of eye (Downward movement) and
intorsion (inward rotation)
• ORIGIN: Originates from the dorsal aspect of the
brainstem
• Travels through the lateral wall of cavernous sinus.
• Exits the skull via the superior orbital fissure.
• Innervates the superior oblique muscle.
• Lesions may cause:-
 Diplopia (double vision).
 Difficulty in looking down and inward.
 Head tilt to compensate for muscle weakness.
11
CRANIAL NERVE – V
TRIGEMINAL NERVE
12
CRANIAL NERVE V- TRIGEMINAL
• It is mixed cranial nerve.
• Fifth cranial nerve is the largest cranial
nerve.
• Trigeminal nerve is the nerve of first
brachial arch.
• It is composed of a small motor root and a
larger sensory root.
• It comprises three branches –
 OPHTHALMIC (V1)
 MAXILLARY (V2)
 MANDIBULAR (V3)
SENSORY
MIXED
13
o The mesencephalic nucleus -
Proprioception
o The chief sensory nucleus – Touch
o The spinal nucleus - Pain &
Temperature.
o Motor Nucleus - Controls muscles of
mastication and other related muscles.
 NUCLEUS OF TRIGEMINAL NERVE
14
 TRIGEMINAL GANGLION
• The trigeminal ganglion is the sensory ganglion
of trigeminal nerve.
• Also called as Semilunar ganglion or gasserian
ganglion.
• Two ganglia are present, one innervating each
side of the face.
• They are located in the Meckel cavity, on the
anterior surface of the petrous portion of the
temporal bone .
• The ganglia are flat and crescent shaped and
measure approximately 1.0 × 2.0cm.
15
OPHTHALMIC NERVE (V1)
• The ophthalmic division is the first branch of the
trigeminal nerve.
• Ophthalmic nerve is sensory.
• Smallest of the three divisions.
• It leaves the cranium and enters the orbit
through the superior orbital fissure
• It divides into its three main branches:
o Nasociliary
o Frontal
o Lacrimal nerves
16
 It is further divided into –
• Frontal
 1. Supratrochlear: Upper eyelid, conjunctiva and
lower part of forehead.
 2. Supraorbital: Frontal air sinus, upper eyelid,
forehead and scalp till vertex
OPHTHALMIC NERVE (V1)
17
OPHTHALMIC NERVE (V1)
• Nasociliary
1. Long ciliary: Sensory to eyeball.
2. Posterior ethmoidal: Sphenoidal air sinus, posterior
ethmoidal air sinuses.
3. Anterior ethmoidal:
o a. Middle and anterior ethmoidal sinuses
o b. Medial internal nasal
o c. Lateral internal nasal
o d. External nasal: The skin over the apex (tip) and
the ala of the nose.
4. Infratrochlear: Both eyelids, side of nose, lacrimal
sac.
• Lacrimal
 Lateral part of upper eyelid; conveys secretomotor
fibres from zygomatic nerve to lacrimal gland.
18
MAXILLARY NERVE (V2)
• As it crosses the pterygopalatine fossa, it gives off branches to the sphenopalatine ganglion, the
posterior superior alveolar (PSA) nerve, and the zygomatic branches.
• It is purely sensory.
• COURSE-
• The maxillary nerve leaves the cranium
through the foramen rotundum (located in
the greater wing of the sphenoid bone).
• Once outside the cranium, it crosses the
uppermost part of the pterygopalatine fossa,
between the pterygoid plates of the
sphenoid bone and the palatine bone.
19
MAXILLARY NERVE (V2)
• It then angles laterally in a groove on the
posterior surface of the maxilla, entering the
orbit through the inferior orbital fissure.
• Within the orbit, it occupies the infraorbital
groove and becomes the infraorbital nerve,
which courses anteriorly into the infraorbital
canal.
• The maxillary division emerges on the
anterior surface of the face through the
infraorbital foramen, where it divides into its
terminal branches, supplying the skin of the
face, nose, lower eyelid, and upper lip.
20
Branch Within the
Cranium
The middle meningeal nerve
 BRANCHES OF MAXILLARY NERVE
The middle meningeal artery
Dura mater
Branches in the
Pterygopalatine
Fossa
The zygomatic nerve
The pterygopalatine nerve
The PSA nerve
Zygomaticotemporal
Zygomaticofacial
Orbit, Nose, Palate, And Pharynx
First, second and Third molars (except for the
mesiobuccal root of the first molar)
Branches within the
infraorbital canal
The MSA nerve
The ASA nerve
Two maxillary premolars and to the mesiobuccal
root of the first molar
The central and lateral incisors and the canine
Branches on the face Inferior palpebral branches
External nasal branches
Superior labial branches
INFRAORBITAL NERVE
21
MANDIBULAR NERVE (V3)
• Largest branch of the trigeminal nerve.
MIXED NERVE
• The two roots exits the cranium separately through the foramen ovale. (The motor root lying medial to the
sensory)
• They unite just outside the skull and form the main trunk of the V3.
TWO ROOTS
A LARGE SENSORY ROOT
A SMALLER MOTOR ROOT
Entire Motor Component Of
The Trigeminal Nerve
THE SENSORY ROOT Trigeminal ganglion
originates
THE MOTOR ROOT The pons and medulla oblongata
originates
THE MAIN TRUNK
remains undivided
for only 2 to 3 mm
Small anterior division
Large posterior division
SPLITS
MAINLY MOTOR
MAINLY SENSORY
22
 BRANCHES & COURSE OF MANDIBULAR NERVE
Branches from the
undivided trunk
THE NERVUS SPINOSUS
(MENINGEAL BRANCH)
THE MEDIAL
PTERYGOID NERVE
REENTERS THE CRANIUM
THROUGH THE FORAMEN SPINOSUM
THE MIDDLE
MENINGEAL ARTERY
THE DURA MATER AND
MASTOID AIR CELLS.
MOTOR NERVE
THE MEDIAL
PTERYGOID MUSCLE
TENSOR VELI PALATINI
TENSOR TYMPANI
23
MANDIBULAR NERVE (V3)
ANTERIOR DIVISION
The Lateral
Pterygoid
Runs forward beneath the lateral
pterygoid, passes between its two
heads, and emerges on the external
surface of the muscle
From this point, it is
known as the buccal nerve
BUCCAL NERVE
THE DEEP TEMPORAL NERVES
MASSETER
LATERAL PTERYGOID NERVES
emerges under the
anterior border of the
masseter muscle
enters the cheek
through the
buccinator muscle
it crosses in front of the
anterior border of the
ramus
Inferior part of the
temporal muscle
At the level of the
occlusal plane of the
mandibular third or
second molar
BUCCAL – SENSORY
(CHEEKS)
24
MANDIBULAR NERVE (V3)
POSTERIOR DIVISION
Runs downwards and medial to
lateral pterygoid muscle
AURICULOTEMPORAL NERVE
LINGUAL NERVE
INFERIOR ALVEOLAR NERVE
It traverses the upper part of the
parotid gland and then crosses the
posterior portion of the zygomatic
arch.
AURICULOTEMPORAL NERVE
SENSORY
AURICULAR
SUPERFICIAL TEMPORAL
ARTICULAR TO TEMPOROMANDIBULAR JOINT
SECRETOMOTOR TO PAROTID GLAND
25
MANDIBULAR NERVE (V3)
LINGUAL NERVE
Descends medial to the lateral
pterygoid muscle
Lies between mandibular ramus and
medial pterygoid
Runs anterior to the inferior
alveolar nerve
Reaches base of tongue near
mandibular third molar
Lies in lateral lingual sulcus under
mucous membrane
Loops medial to submandibular duct
[Whartons duct]
Ends at the sublingual gland as
terminal branches
THE LINGUAL
NERVE
SENSOR
Y
ANTERIOR TWO-
THIRDS OF THE
TONGUE
• LINGUAL NERVE supplies fibers for general sensation, whereas the
chorda tympani (a branch of the facial nerve) supplies fibers for taste.
26
MANDIBULAR NERVE (V3)
THE LARGEST BRANCH OF THE MANDIBULAR
DIVISION
THE INFERIOR ALVEOLAR NERVE
Descends medial to the
lateral pterygoid muscle
Passes lateroposterior to
the lingual nerve
Reaches region between sphenomandibular
ligament and medial mandibular ramus
Enters mandibular canal through
mandibular foramen
Travels anteriorly within mandibular
canal accompanied by inferior
alveolar artery and vein
Mylohyoid Nerve
Dental Plexus : Supplies mandibular
posterior teeth and buccal
periodontal tissues
Reaches mental foramen
Mental Nerve**: Exits through mental foramen, sensory
to chin, lower lip, and adjacent mucosa
Incisive Nerve**: Stays within mandibular canal, forms
plexus for pulpal innervation of anterior teeth (incisors,
canine, first premolar)
Sensory to mental protuberance and
sometimes mandibular molars
Exits before
canal entry
Motor to mylohyoid and
anterior digastric
27
APPLIED ANATOMY
TRIGEMINAL NEURALGIA
• Trigeminal neuralgia (TN) is defined as sudden, usually unilateral, severe, brief, stabbing,
lancinating, paroxysmal, recurring pain in the distribution of one or more branches of 5th
cranial nerve.
(Tic Douloureux)
• Trigeminal - Cranial nerve V
• Neur - Nerve related
• Algia - Pain
Etiology:  Idiopathic
 Vascular compression
 Progressive degeneration
 Intra-cranial tumor
 Peripheral nerve injury
 Older adults, Female predilection
 Right side affected more
 Intense shooting stabbing pain
 Electric shock-like
 Unilateral
 Maxillary > Mandibular > Ophthalmic
 Trigger zones
 Spasmodic contraction of facial muscle
Clinical
features:
28
Management
1.Support and Education.
2.Pharmacological.
3.Surgical.
• No treatment modality to permanently eliminate
• Managed initially with medication
• Surgical if refractory to medical management develops serious side effects
• Make patient aware that it is not life
threatening.
• Realize the severity of condition.
• Educate for:
• Reassurance and Follow up.
 Support and Education:
 Causes
 Therapies
 Treatment :
• CARBAMAZEPINE 100mg 3 times a day for 1.5 weeks
• SODIUM VALPROATE 600 mg/ day
• CLONAZEPAM 1.5mg/day
 Surgical procedures:
• Using gamma knife
• Percutaneous balloon compression
• Percutaneous glycerol rhizotomy
• Percutaneous stereotactic rhizotomy
29
Treatment :
• Botulinum toxin injections
• Resection of nerve
FREY’S SYNDROME
• Damage to auriculotemporal nerve & subsequent
reinnervation of sweat glands
Clinical features :
• Flushing & sweating on the involved side of the face.
30
IATROGENIC CAUSES OF TRIGEMINAL NERVE DAMAGE
• Local anaesthetic injections (needle trauma).
• Tooth extractions (e.g., third molars).
• Endodontic over- instrumentation.
• Dental implant misplacement.
• Periodontal or orthognathic surgeries.
• Maxillofacial Surgeries: Fracture reduction or tumour excision.
• Others: Thermal injuries (laser/electrosurgery).
31
IATROGENIC CAUSES OF TRIGEMINAL NERVE DAMAGE
MANAGEMENT
 Conservative:
• Corticosteroids for inflammation.
• Neuropathic pain medications (gabapentin, pregabalin).
• Low-level laser therapy (LLLT) for nerve healing.
• Vitamin B complex for nerve support.
 Surgical:
• Nerve decompression or repair (grafting, neurolysis).
• Repositioning implants or removing compressive materials.
 Adjuncts:
• Physiotherapy and psychological support.
32
CRANIAL NERVE VI- ABDUSENT
• The sixth cranial nerve, or Abducens Nerve, is a
motor nerve.
• FUNCTION: Controls the lateral rectus muscle for
eye abduction.
• Origin: Abducens nucleus in the pons.
• Emerges at the pontomedullary junction.
• Passes through cisterna pontis, cavernous sinus,
and superior orbital fissure.
• Termination: Innervates the lateral rectus muscle.
• Sixth nerve paralysis causes medial squint and
diplopia.
33
CRANIAL NERVE VII – FACIAL
• Facial nerve is mixed nerve.
• This nerve allows us to laugh, cry, smile, frown
hence known as "The Nerve of Facial
Expression“
• "PES ANSERINUS“ may also be used to describe
the branching point of the facial nerve (CN-VII)
within the parotid gland.
• Motor Function: Controls muscles responsible for facial
expressions.
• Sensory Function: Provides taste sensations from the
anterior two-thirds of the tongue.
34
CRANIAL NERVE VII – FACIAL
• Origin: The facial nerve originates in the
pons of the brainstem.
• Pathway: It travels through the internal
acoustic meatus, exits the skull via the
stylomastoid foramen, and passes
through the parotid gland.
NEUCLEUS OF FACIAL NERVE
1. Motor nucleus
2. Superior salivatory nucleus
3. Lacrimatory nucleus
4. Nucleus of the tractus solitarius –
Gustatory
35
CRANIAL NERVE VII – FACIAL
Cervical
BRANCHES
Facial canal
Nerve to stapedius
Greater petrosal nerve
Chorda tympani
STYLOMASTOID FORAMEN
Posterior auricular
Nerve to stylohyoid
Nerve to digastric
(posterior belly)
IN FACE
Temporal
Zygomatic
Buccal
Marginal mandibular
36
CRANIAL NERVE VII – FACIAL
CLINICAL TESTING
 Motor function : Ask the patient to raise eyebrows, wrinkle,
close eyes tightly, show teeth, blow out cheek, whistle.
 Sensory function : Sweet, salty, sour, bitter taste.
 Secretory function :
 Lacrimation
 Schirmer’s test
 Nasolacrimal reflex
 Salivation
 Reflexes :
 Corneal reflex
 Stapedial reflex
37
BELL’S PALSY
 Idiopathic unilateral lower motor neuron paralysis of sudden onset.
 Etiology :
 Trauma
 Infection
 Neoplastic
 Idiopathic
 Clinical Features :
 Pain behind ear (mastoid foramen).
 Affection of taste and hearing.
 Inability to raise eyebrow.
 Inability to close eye on affected side.
 Flattening of nasolabial fold.
 Accumulation of food inside the cheek (affected side).
 Dropping corner of mouth.
 Drippling of saliva.
38
BELL’S PALSY
 Treatment :
 No standard course of treatment – Symptomatic treatment
 Steroids - prednisolone 1mg/kg body wt for 10-14 days with a gradual
tapering
 Anti-viral drug
 Analgesics
 Eye protection
39
CRANIAL NERVE VIII – VESTIBULOCOCHLEAR
• It is sensory nerve.
• Origin: Pons and medulla junction.
• Pathway:
 Enters the internal acoustic meatus.
 Divides into cochlear and vestibular
branches
40
CRANIAL NERVE VIII – VESTIBULOCOCHLEAR
• Cochlear Division (Hearing) Pathway:
 Cochlea Spiral ganglion Cochlear nuclei
→ → →
Auditory cortex (temporal lobe).
• Function:
 Detects sound waves.
 Transmits auditory information.
• Vestibular Division (Balance) Pathway:
 Semicircular canals, utricle, and saccule →
Vestibular ganglion Vestibular nuclei.
→
• Function:
 Maintains equilibrium.
 Coordinates head and eye movements.
COMMON DISORDERS-
• Vestibular Disorders:- Vertigo
• Cochlear Disorders:- Sensorineural
hearing loss & Tinnitus.
41
CRANIAL NERVE IX – GLOSSOPHARYNGEAL
• It is a mixed nerve
• Origin: Medulla oblongata
• NUCLEUS OF GLOSSOPHARYNGEAL NERVE
 Nucleus ambiguus
 Inferior salivatory nucleus
 Solitary nucleus
• Exit: Leaves the skull through the jugular
foramen.
42
CRANIAL NERVE IX – GLOSSOPHARYNGEAL
• Branches:
 Tympanic nerve
 Carotid sinus nerve
 Pharyngeal branches
 Tonsillar branches
 Lingual branches
 Muscular branches - Stylopharyngeus
• Motor Function:
 Stylopharyngeus muscle (aids in swallowing).
• Sensory Function:
 Taste from the posterior one-third of the tongue.
 Sensation from the pharynx, tonsils, middle ear, and
posterior tongue.
43
• Rare neuropathic condition causing severe, stabbing pain
along the glossopharyngeal nerve.
• Symptoms:
 Sudden, sharp pain in the throat, tonsils, tongue (posterior
one-third), and ear.
 Triggered by swallowing, speaking, coughing, or yawning.
 Usually unilateral.
• Causes:
 Vascular compression.
 Tumors
 Idiopathic (unknown cause).
• Treatment:
 Carbamazepine
 Surgical section of nerve
 Microvascular decompression
GLOSSOPHARYNGEAL NEURALGIA
44
CRANIAL NERVE X - VAGUS
• It is a mixed nerve.
• “Wandering nerve" due to its extensive distribution from the
brainstem to the abdomen.
• Origin: Medulla oblongata
• Exits : The skull through the jugular foramen.
• Motor:
 Pharyngeal muscles (except stylopharyngeus).
 Laryngeal muscles (voice production).
 Palatoglossus of tongue.
• Sensory:
 External ear and external auditory canal
 Pharynx, larynx, and thoracic/abdominal viscera.
• Parasympathetic to heart, lungs, and digestive tract.
45
CRANIAL NERVE X - VAGUS
• APPLIED ANATOMY
• Testing:
 Gag reflex – ABSENT
 Uvula deviates to the unaffected side.
• Disorders:
 Hoarseness
 Dysphagia
 Bradycardia
• Surgical Risk:
 Recurrent laryngeal nerve injury in thyroid surgery
46
CRANIAL NERVE XI - ACCESSORY
• Primarily motor in function.
• Composed of two parts:
 Spinal root (primary component).
 Cranial root (smaller).
• Cranial Root originates - from the medulla
oblongata.
• Spinal Root originates - from C1–C5 spinal
segments.
 Ascends through the foramen magnum to join
the cranial root.
• Exits - the skull via the jugular foramen.
• Cranial part merges with the vagus nerve.
• Spinal part innervates specific muscles.
 Trapezius muscle: Shoulder movements.
 Sternocleidomastoid muscle: Head rotation and neck
flexion.
47
CRANIAL NERVE XI - ACCESSORY
 Testing the Nerve
• Sternocleidomastoid Test: Ask the patient to
rotate their head against resistance.
• Normal response:
 The patient can turn their head forcefully
against resistance.
• Trapezius Test: Ask the patient to shrug their
shoulders against resistance.
• Normal response:
 The patient should be able to shrug both
shoulders symmetrically and against
resistance.
48
CRANIAL NERVE XII - HYPOGLOSSAL
• It is a purely motor nerve.
• Functions: Controls the movements of the tongue
for speech, swallowing, and mastication.
• Origin: Arises from the hypoglossal nucleus in the
medulla oblongata.
• Exits the skull through the hypoglossal canal.
• Travels downward and forward to reach the tongue
muscles.
• It runs with the Ansa cervicalis, which innervates
some infrahyoid muscles.
49
CRANIAL NERVE XII - HYPOGLOSSAL
• Supplies all intrinsic and extrinsic muscles of the
tongue, except the palatoglossus (supplied by the
vagus nerve).
 BRANCHES
 Meningeal branch
 Descending branch
 Nerve to thyrohyoid and geniohyoid muscles
 Muscular branches
 Intrinsic muscles: Change the shape of the tongue
(e.g., longitudinal, transverse, vertical muscles).
 Extrinsic muscles: Move the tongue (e.g.,
genioglossus, hyoglossus, styloglossus).
50
CRANIAL NERVE XII - HYPOGLOSSAL
 APPLIED ANATOMY
LOWER MOTOR
NEURON LESION
UPPER MOTOR
NEURON LESION
TONGUE DEVIATES
TOWARDS OPPOSITE SIDE
TONGUE DEVIATES
TOWARDS SAME SIDE
51
CONCLUSION
• Cranial nerves play a crucial role in dental practice, influencing sensation, motor function, and reflexes of the
head and neck.
• Understanding cranial nerve anatomy and function is essential for diagnosing and managing orofacial pain,
nerve injuries, and neurological disorders.
• Key cranial nerves in dentistry include:
 Trigeminal Nerve (CN V): Sensory supply to the face and motor control for mastication.
 Facial Nerve (CN VII): Motor control for facial expression and parasympathetic functions.
 Glossopharyngeal (CN IX) and Vagus Nerve (CN X): Essential for swallowing, gag reflex, and speech.
 Hypoglossal Nerve (CN XII): Controls tongue movements critical for speech and chewing.
• A thorough understanding of cranial nerve function ensures precise clinical assessments, effective anesthesia
administration, and accurate diagnosis of pathologies.
• By integrating cranial nerve knowledge into dental practice, clinicians can enhance patient outcomes and
safety.
52
REFERENCES
1) Textbook Of Human Anatomy, BD Chaurasia, Vol 3 & 4, 7th
Edition.
2) Handbook Of Local Anesthesia, Stanley F. Malamed, 7th
Edition.
3) Textbook Of Oral And Maxillofacial Surgeries, Neelima Malik, 4th
Edition.
4) Textbook Of Oral Medicine, Burket’s, 10th Edition.
53
Thank You!
54

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powerpoint presentation on cranial nerves

  • 1. CRANIAL NERVES 1 Presenter : Shyam Moderator : Dr. Parimala No. of slides - 54
  • 2. Contents 02 04 • INTRODUCTION • TYPES OF NERVES • CLASSIFICAION OF CRANIAL NERVES • CRANIAL NERVES (1 – 12) • CONCLUSION • REFRENCES 2
  • 3. INTRODUCTION 04 • Cranial nerves are those nerves which arises from brain and brain stem rather than spinal cord. • Nerve arising from the spinal cord are called peripheral nerves. • There are 12 pairs of cranial nerves, and these nerves exits skull through foramina. 3
  • 4. 02 04 I. Olfactory II. Optic III. Oculomotor IV. Trochlear V. Trigeminal VI. Abducent VII.Facial VIII.Vestibulo-cochlear IX. Glossopharyngeal X. Vagus XI. Accessory XII.Hypoglossal THE 12 CRANIAL NERVES OH OH OH TRY TRY AGAIN FAILURE VICTORY GIVE VALUE AND HAPPINESS MNEMONIC 4
  • 5. Types of Nerves  Motor Nerves-  Function: Transmit motor commands from the central nervous system (CNS) to muscles and glands.  Role: Enable movement and actions, including both voluntary (e.g., walking) and involuntary (e.g., reflexes) movements.  Key Points: • Efferent pathway: Carries signals away from the CNS. • Activates skeletal, smooth, or cardiac muscles.  Sensory Nerves-  Function: Carry sensory information from the body’s periphery to the CNS.  Role: Responsible for processing external stimuli such as touch, temperature, pain, and proprioception.  Key Points: •Afferent pathway: Transmits signals to the CNS. •Enables perception of the environment and body’s condition. 5
  • 6.  Mixed Nerves-  Function: Perform both sensory and motor functions.  Role: Provide dual functionality: sensory input to the CNS and motor output to muscles or glands.  Key Points: •Combine afferent (sensory) and efferent (motor) fibers. •Essential for coordinated body functions. 6
  • 7. CLASSIFICATION OF CRANIAL NERVES SENSORY CRANIAL NERVES • OLFACTORY • OPTIC • VESTIBULOCOCHLEAR MOTOR CRANIAL NERVES • OCCULOMOTOR • TROCLEAR • ABDUCENT • ACCESSORY • HYPOGLOSSAL MIXED CRANIAL NERVES • TRIGEMINAL • FACIAL • GLOSSOPHARYNGEAL • VAGUS 7
  • 8. CRANIAL NERVE I - OLFACTORY • It is sensory nerve. • Shortest cranial nerve • Carries impulses for sense of smell. • ORIGIN: Olfactory epithelium • Axons Passes through the cribriform plate of the ethmoid bone • Synapse in the olfactory bulb. • Lesions may cause:  Anosmia: Loss of smell.  Hyposmia: Reduced sense of smell. 8
  • 9. CRANIAL NERVE II - OPTIC • It is sensory nerve. • It carry impulses for vision. • ORIGIN: Back of eyeball/ retina of eye. • Axons converge to form the optic nerve. • Passes through the optic canal in the sphenoid bone. • Forms the optic chiasma, where partial crossing of fibers occurs. • Continues as the optic tract to the lateral geniculate body of the thalamus • Relays visual information to the occipital lobe (visual cortex). • Lesions may cause:-  Blindness (complete optic nerve damage)  Visual field defects (e.g., hemianopia) 9
  • 10. CRANIAL NERVE III – OCULOMOTOR • It is Motor nerve • Function: Eye movement and pupil constriction • ORIGIN: Oculomotor nucleus in the midbrain. • Passes through the cavernous sinus • Exits skull via the superior orbital fissure • Supplies to all extraocular muscles except superior oblique and lateral rectus. (SO4, LR6, AO3) • Lesions may cause: • Ptosis: Drooping eyelid • Diplopia: Double vision • Mydriasis: Dilated pupil • Eye deviation: "Down and out" position due to unopposed action of lateral rectus and superior oblique 10
  • 11. CRANIAL NERVE IV- TROCHLEAR • It is motor nerve. • It has longest intracranial course, but also the thinnest. • Function: Depression of eye (Downward movement) and intorsion (inward rotation) • ORIGIN: Originates from the dorsal aspect of the brainstem • Travels through the lateral wall of cavernous sinus. • Exits the skull via the superior orbital fissure. • Innervates the superior oblique muscle. • Lesions may cause:-  Diplopia (double vision).  Difficulty in looking down and inward.  Head tilt to compensate for muscle weakness. 11
  • 12. CRANIAL NERVE – V TRIGEMINAL NERVE 12
  • 13. CRANIAL NERVE V- TRIGEMINAL • It is mixed cranial nerve. • Fifth cranial nerve is the largest cranial nerve. • Trigeminal nerve is the nerve of first brachial arch. • It is composed of a small motor root and a larger sensory root. • It comprises three branches –  OPHTHALMIC (V1)  MAXILLARY (V2)  MANDIBULAR (V3) SENSORY MIXED 13
  • 14. o The mesencephalic nucleus - Proprioception o The chief sensory nucleus – Touch o The spinal nucleus - Pain & Temperature. o Motor Nucleus - Controls muscles of mastication and other related muscles.  NUCLEUS OF TRIGEMINAL NERVE 14
  • 15.  TRIGEMINAL GANGLION • The trigeminal ganglion is the sensory ganglion of trigeminal nerve. • Also called as Semilunar ganglion or gasserian ganglion. • Two ganglia are present, one innervating each side of the face. • They are located in the Meckel cavity, on the anterior surface of the petrous portion of the temporal bone . • The ganglia are flat and crescent shaped and measure approximately 1.0 × 2.0cm. 15
  • 16. OPHTHALMIC NERVE (V1) • The ophthalmic division is the first branch of the trigeminal nerve. • Ophthalmic nerve is sensory. • Smallest of the three divisions. • It leaves the cranium and enters the orbit through the superior orbital fissure • It divides into its three main branches: o Nasociliary o Frontal o Lacrimal nerves 16
  • 17.  It is further divided into – • Frontal  1. Supratrochlear: Upper eyelid, conjunctiva and lower part of forehead.  2. Supraorbital: Frontal air sinus, upper eyelid, forehead and scalp till vertex OPHTHALMIC NERVE (V1) 17
  • 18. OPHTHALMIC NERVE (V1) • Nasociliary 1. Long ciliary: Sensory to eyeball. 2. Posterior ethmoidal: Sphenoidal air sinus, posterior ethmoidal air sinuses. 3. Anterior ethmoidal: o a. Middle and anterior ethmoidal sinuses o b. Medial internal nasal o c. Lateral internal nasal o d. External nasal: The skin over the apex (tip) and the ala of the nose. 4. Infratrochlear: Both eyelids, side of nose, lacrimal sac. • Lacrimal  Lateral part of upper eyelid; conveys secretomotor fibres from zygomatic nerve to lacrimal gland. 18
  • 19. MAXILLARY NERVE (V2) • As it crosses the pterygopalatine fossa, it gives off branches to the sphenopalatine ganglion, the posterior superior alveolar (PSA) nerve, and the zygomatic branches. • It is purely sensory. • COURSE- • The maxillary nerve leaves the cranium through the foramen rotundum (located in the greater wing of the sphenoid bone). • Once outside the cranium, it crosses the uppermost part of the pterygopalatine fossa, between the pterygoid plates of the sphenoid bone and the palatine bone. 19
  • 20. MAXILLARY NERVE (V2) • It then angles laterally in a groove on the posterior surface of the maxilla, entering the orbit through the inferior orbital fissure. • Within the orbit, it occupies the infraorbital groove and becomes the infraorbital nerve, which courses anteriorly into the infraorbital canal. • The maxillary division emerges on the anterior surface of the face through the infraorbital foramen, where it divides into its terminal branches, supplying the skin of the face, nose, lower eyelid, and upper lip. 20
  • 21. Branch Within the Cranium The middle meningeal nerve  BRANCHES OF MAXILLARY NERVE The middle meningeal artery Dura mater Branches in the Pterygopalatine Fossa The zygomatic nerve The pterygopalatine nerve The PSA nerve Zygomaticotemporal Zygomaticofacial Orbit, Nose, Palate, And Pharynx First, second and Third molars (except for the mesiobuccal root of the first molar) Branches within the infraorbital canal The MSA nerve The ASA nerve Two maxillary premolars and to the mesiobuccal root of the first molar The central and lateral incisors and the canine Branches on the face Inferior palpebral branches External nasal branches Superior labial branches INFRAORBITAL NERVE 21
  • 22. MANDIBULAR NERVE (V3) • Largest branch of the trigeminal nerve. MIXED NERVE • The two roots exits the cranium separately through the foramen ovale. (The motor root lying medial to the sensory) • They unite just outside the skull and form the main trunk of the V3. TWO ROOTS A LARGE SENSORY ROOT A SMALLER MOTOR ROOT Entire Motor Component Of The Trigeminal Nerve THE SENSORY ROOT Trigeminal ganglion originates THE MOTOR ROOT The pons and medulla oblongata originates THE MAIN TRUNK remains undivided for only 2 to 3 mm Small anterior division Large posterior division SPLITS MAINLY MOTOR MAINLY SENSORY 22
  • 23.  BRANCHES & COURSE OF MANDIBULAR NERVE Branches from the undivided trunk THE NERVUS SPINOSUS (MENINGEAL BRANCH) THE MEDIAL PTERYGOID NERVE REENTERS THE CRANIUM THROUGH THE FORAMEN SPINOSUM THE MIDDLE MENINGEAL ARTERY THE DURA MATER AND MASTOID AIR CELLS. MOTOR NERVE THE MEDIAL PTERYGOID MUSCLE TENSOR VELI PALATINI TENSOR TYMPANI 23
  • 24. MANDIBULAR NERVE (V3) ANTERIOR DIVISION The Lateral Pterygoid Runs forward beneath the lateral pterygoid, passes between its two heads, and emerges on the external surface of the muscle From this point, it is known as the buccal nerve BUCCAL NERVE THE DEEP TEMPORAL NERVES MASSETER LATERAL PTERYGOID NERVES emerges under the anterior border of the masseter muscle enters the cheek through the buccinator muscle it crosses in front of the anterior border of the ramus Inferior part of the temporal muscle At the level of the occlusal plane of the mandibular third or second molar BUCCAL – SENSORY (CHEEKS) 24
  • 25. MANDIBULAR NERVE (V3) POSTERIOR DIVISION Runs downwards and medial to lateral pterygoid muscle AURICULOTEMPORAL NERVE LINGUAL NERVE INFERIOR ALVEOLAR NERVE It traverses the upper part of the parotid gland and then crosses the posterior portion of the zygomatic arch. AURICULOTEMPORAL NERVE SENSORY AURICULAR SUPERFICIAL TEMPORAL ARTICULAR TO TEMPOROMANDIBULAR JOINT SECRETOMOTOR TO PAROTID GLAND 25
  • 26. MANDIBULAR NERVE (V3) LINGUAL NERVE Descends medial to the lateral pterygoid muscle Lies between mandibular ramus and medial pterygoid Runs anterior to the inferior alveolar nerve Reaches base of tongue near mandibular third molar Lies in lateral lingual sulcus under mucous membrane Loops medial to submandibular duct [Whartons duct] Ends at the sublingual gland as terminal branches THE LINGUAL NERVE SENSOR Y ANTERIOR TWO- THIRDS OF THE TONGUE • LINGUAL NERVE supplies fibers for general sensation, whereas the chorda tympani (a branch of the facial nerve) supplies fibers for taste. 26
  • 27. MANDIBULAR NERVE (V3) THE LARGEST BRANCH OF THE MANDIBULAR DIVISION THE INFERIOR ALVEOLAR NERVE Descends medial to the lateral pterygoid muscle Passes lateroposterior to the lingual nerve Reaches region between sphenomandibular ligament and medial mandibular ramus Enters mandibular canal through mandibular foramen Travels anteriorly within mandibular canal accompanied by inferior alveolar artery and vein Mylohyoid Nerve Dental Plexus : Supplies mandibular posterior teeth and buccal periodontal tissues Reaches mental foramen Mental Nerve**: Exits through mental foramen, sensory to chin, lower lip, and adjacent mucosa Incisive Nerve**: Stays within mandibular canal, forms plexus for pulpal innervation of anterior teeth (incisors, canine, first premolar) Sensory to mental protuberance and sometimes mandibular molars Exits before canal entry Motor to mylohyoid and anterior digastric 27
  • 28. APPLIED ANATOMY TRIGEMINAL NEURALGIA • Trigeminal neuralgia (TN) is defined as sudden, usually unilateral, severe, brief, stabbing, lancinating, paroxysmal, recurring pain in the distribution of one or more branches of 5th cranial nerve. (Tic Douloureux) • Trigeminal - Cranial nerve V • Neur - Nerve related • Algia - Pain Etiology:  Idiopathic  Vascular compression  Progressive degeneration  Intra-cranial tumor  Peripheral nerve injury  Older adults, Female predilection  Right side affected more  Intense shooting stabbing pain  Electric shock-like  Unilateral  Maxillary > Mandibular > Ophthalmic  Trigger zones  Spasmodic contraction of facial muscle Clinical features: 28
  • 29. Management 1.Support and Education. 2.Pharmacological. 3.Surgical. • No treatment modality to permanently eliminate • Managed initially with medication • Surgical if refractory to medical management develops serious side effects • Make patient aware that it is not life threatening. • Realize the severity of condition. • Educate for: • Reassurance and Follow up.  Support and Education:  Causes  Therapies  Treatment : • CARBAMAZEPINE 100mg 3 times a day for 1.5 weeks • SODIUM VALPROATE 600 mg/ day • CLONAZEPAM 1.5mg/day  Surgical procedures: • Using gamma knife • Percutaneous balloon compression • Percutaneous glycerol rhizotomy • Percutaneous stereotactic rhizotomy 29
  • 30. Treatment : • Botulinum toxin injections • Resection of nerve FREY’S SYNDROME • Damage to auriculotemporal nerve & subsequent reinnervation of sweat glands Clinical features : • Flushing & sweating on the involved side of the face. 30
  • 31. IATROGENIC CAUSES OF TRIGEMINAL NERVE DAMAGE • Local anaesthetic injections (needle trauma). • Tooth extractions (e.g., third molars). • Endodontic over- instrumentation. • Dental implant misplacement. • Periodontal or orthognathic surgeries. • Maxillofacial Surgeries: Fracture reduction or tumour excision. • Others: Thermal injuries (laser/electrosurgery). 31
  • 32. IATROGENIC CAUSES OF TRIGEMINAL NERVE DAMAGE MANAGEMENT  Conservative: • Corticosteroids for inflammation. • Neuropathic pain medications (gabapentin, pregabalin). • Low-level laser therapy (LLLT) for nerve healing. • Vitamin B complex for nerve support.  Surgical: • Nerve decompression or repair (grafting, neurolysis). • Repositioning implants or removing compressive materials.  Adjuncts: • Physiotherapy and psychological support. 32
  • 33. CRANIAL NERVE VI- ABDUSENT • The sixth cranial nerve, or Abducens Nerve, is a motor nerve. • FUNCTION: Controls the lateral rectus muscle for eye abduction. • Origin: Abducens nucleus in the pons. • Emerges at the pontomedullary junction. • Passes through cisterna pontis, cavernous sinus, and superior orbital fissure. • Termination: Innervates the lateral rectus muscle. • Sixth nerve paralysis causes medial squint and diplopia. 33
  • 34. CRANIAL NERVE VII – FACIAL • Facial nerve is mixed nerve. • This nerve allows us to laugh, cry, smile, frown hence known as "The Nerve of Facial Expression“ • "PES ANSERINUS“ may also be used to describe the branching point of the facial nerve (CN-VII) within the parotid gland. • Motor Function: Controls muscles responsible for facial expressions. • Sensory Function: Provides taste sensations from the anterior two-thirds of the tongue. 34
  • 35. CRANIAL NERVE VII – FACIAL • Origin: The facial nerve originates in the pons of the brainstem. • Pathway: It travels through the internal acoustic meatus, exits the skull via the stylomastoid foramen, and passes through the parotid gland. NEUCLEUS OF FACIAL NERVE 1. Motor nucleus 2. Superior salivatory nucleus 3. Lacrimatory nucleus 4. Nucleus of the tractus solitarius – Gustatory 35
  • 36. CRANIAL NERVE VII – FACIAL Cervical BRANCHES Facial canal Nerve to stapedius Greater petrosal nerve Chorda tympani STYLOMASTOID FORAMEN Posterior auricular Nerve to stylohyoid Nerve to digastric (posterior belly) IN FACE Temporal Zygomatic Buccal Marginal mandibular 36
  • 37. CRANIAL NERVE VII – FACIAL CLINICAL TESTING  Motor function : Ask the patient to raise eyebrows, wrinkle, close eyes tightly, show teeth, blow out cheek, whistle.  Sensory function : Sweet, salty, sour, bitter taste.  Secretory function :  Lacrimation  Schirmer’s test  Nasolacrimal reflex  Salivation  Reflexes :  Corneal reflex  Stapedial reflex 37
  • 38. BELL’S PALSY  Idiopathic unilateral lower motor neuron paralysis of sudden onset.  Etiology :  Trauma  Infection  Neoplastic  Idiopathic  Clinical Features :  Pain behind ear (mastoid foramen).  Affection of taste and hearing.  Inability to raise eyebrow.  Inability to close eye on affected side.  Flattening of nasolabial fold.  Accumulation of food inside the cheek (affected side).  Dropping corner of mouth.  Drippling of saliva. 38
  • 39. BELL’S PALSY  Treatment :  No standard course of treatment – Symptomatic treatment  Steroids - prednisolone 1mg/kg body wt for 10-14 days with a gradual tapering  Anti-viral drug  Analgesics  Eye protection 39
  • 40. CRANIAL NERVE VIII – VESTIBULOCOCHLEAR • It is sensory nerve. • Origin: Pons and medulla junction. • Pathway:  Enters the internal acoustic meatus.  Divides into cochlear and vestibular branches 40
  • 41. CRANIAL NERVE VIII – VESTIBULOCOCHLEAR • Cochlear Division (Hearing) Pathway:  Cochlea Spiral ganglion Cochlear nuclei → → → Auditory cortex (temporal lobe). • Function:  Detects sound waves.  Transmits auditory information. • Vestibular Division (Balance) Pathway:  Semicircular canals, utricle, and saccule → Vestibular ganglion Vestibular nuclei. → • Function:  Maintains equilibrium.  Coordinates head and eye movements. COMMON DISORDERS- • Vestibular Disorders:- Vertigo • Cochlear Disorders:- Sensorineural hearing loss & Tinnitus. 41
  • 42. CRANIAL NERVE IX – GLOSSOPHARYNGEAL • It is a mixed nerve • Origin: Medulla oblongata • NUCLEUS OF GLOSSOPHARYNGEAL NERVE  Nucleus ambiguus  Inferior salivatory nucleus  Solitary nucleus • Exit: Leaves the skull through the jugular foramen. 42
  • 43. CRANIAL NERVE IX – GLOSSOPHARYNGEAL • Branches:  Tympanic nerve  Carotid sinus nerve  Pharyngeal branches  Tonsillar branches  Lingual branches  Muscular branches - Stylopharyngeus • Motor Function:  Stylopharyngeus muscle (aids in swallowing). • Sensory Function:  Taste from the posterior one-third of the tongue.  Sensation from the pharynx, tonsils, middle ear, and posterior tongue. 43
  • 44. • Rare neuropathic condition causing severe, stabbing pain along the glossopharyngeal nerve. • Symptoms:  Sudden, sharp pain in the throat, tonsils, tongue (posterior one-third), and ear.  Triggered by swallowing, speaking, coughing, or yawning.  Usually unilateral. • Causes:  Vascular compression.  Tumors  Idiopathic (unknown cause). • Treatment:  Carbamazepine  Surgical section of nerve  Microvascular decompression GLOSSOPHARYNGEAL NEURALGIA 44
  • 45. CRANIAL NERVE X - VAGUS • It is a mixed nerve. • “Wandering nerve" due to its extensive distribution from the brainstem to the abdomen. • Origin: Medulla oblongata • Exits : The skull through the jugular foramen. • Motor:  Pharyngeal muscles (except stylopharyngeus).  Laryngeal muscles (voice production).  Palatoglossus of tongue. • Sensory:  External ear and external auditory canal  Pharynx, larynx, and thoracic/abdominal viscera. • Parasympathetic to heart, lungs, and digestive tract. 45
  • 46. CRANIAL NERVE X - VAGUS • APPLIED ANATOMY • Testing:  Gag reflex – ABSENT  Uvula deviates to the unaffected side. • Disorders:  Hoarseness  Dysphagia  Bradycardia • Surgical Risk:  Recurrent laryngeal nerve injury in thyroid surgery 46
  • 47. CRANIAL NERVE XI - ACCESSORY • Primarily motor in function. • Composed of two parts:  Spinal root (primary component).  Cranial root (smaller). • Cranial Root originates - from the medulla oblongata. • Spinal Root originates - from C1–C5 spinal segments.  Ascends through the foramen magnum to join the cranial root. • Exits - the skull via the jugular foramen. • Cranial part merges with the vagus nerve. • Spinal part innervates specific muscles.  Trapezius muscle: Shoulder movements.  Sternocleidomastoid muscle: Head rotation and neck flexion. 47
  • 48. CRANIAL NERVE XI - ACCESSORY  Testing the Nerve • Sternocleidomastoid Test: Ask the patient to rotate their head against resistance. • Normal response:  The patient can turn their head forcefully against resistance. • Trapezius Test: Ask the patient to shrug their shoulders against resistance. • Normal response:  The patient should be able to shrug both shoulders symmetrically and against resistance. 48
  • 49. CRANIAL NERVE XII - HYPOGLOSSAL • It is a purely motor nerve. • Functions: Controls the movements of the tongue for speech, swallowing, and mastication. • Origin: Arises from the hypoglossal nucleus in the medulla oblongata. • Exits the skull through the hypoglossal canal. • Travels downward and forward to reach the tongue muscles. • It runs with the Ansa cervicalis, which innervates some infrahyoid muscles. 49
  • 50. CRANIAL NERVE XII - HYPOGLOSSAL • Supplies all intrinsic and extrinsic muscles of the tongue, except the palatoglossus (supplied by the vagus nerve).  BRANCHES  Meningeal branch  Descending branch  Nerve to thyrohyoid and geniohyoid muscles  Muscular branches  Intrinsic muscles: Change the shape of the tongue (e.g., longitudinal, transverse, vertical muscles).  Extrinsic muscles: Move the tongue (e.g., genioglossus, hyoglossus, styloglossus). 50
  • 51. CRANIAL NERVE XII - HYPOGLOSSAL  APPLIED ANATOMY LOWER MOTOR NEURON LESION UPPER MOTOR NEURON LESION TONGUE DEVIATES TOWARDS OPPOSITE SIDE TONGUE DEVIATES TOWARDS SAME SIDE 51
  • 52. CONCLUSION • Cranial nerves play a crucial role in dental practice, influencing sensation, motor function, and reflexes of the head and neck. • Understanding cranial nerve anatomy and function is essential for diagnosing and managing orofacial pain, nerve injuries, and neurological disorders. • Key cranial nerves in dentistry include:  Trigeminal Nerve (CN V): Sensory supply to the face and motor control for mastication.  Facial Nerve (CN VII): Motor control for facial expression and parasympathetic functions.  Glossopharyngeal (CN IX) and Vagus Nerve (CN X): Essential for swallowing, gag reflex, and speech.  Hypoglossal Nerve (CN XII): Controls tongue movements critical for speech and chewing. • A thorough understanding of cranial nerve function ensures precise clinical assessments, effective anesthesia administration, and accurate diagnosis of pathologies. • By integrating cranial nerve knowledge into dental practice, clinicians can enhance patient outcomes and safety. 52
  • 53. REFERENCES 1) Textbook Of Human Anatomy, BD Chaurasia, Vol 3 & 4, 7th Edition. 2) Handbook Of Local Anesthesia, Stanley F. Malamed, 7th Edition. 3) Textbook Of Oral And Maxillofacial Surgeries, Neelima Malik, 4th Edition. 4) Textbook Of Oral Medicine, Burket’s, 10th Edition. 53

Editor's Notes

  • #11: Vision is single as long as eyes look above the horizontal plane
  • #13: Vision is single as long as eyes look above the horizontal plane
  • #15: Sensory root fibers enter the concave portion of each crescent, and the three sensory divisions of the trigeminal nerve exit from the convexity
  • #21: Immediately after separating from the trigeminal ganglion, the maxillary division gives off a small branch, the middle meningeal nerve, which travels with the middle meningeal artery to provide sensory innervation to the dura mater. - After exiting the cranium through the foramen rotundum, the maxillary division crosses the pterygopalatine fossa. In this fossa, several branches are given off , the zygomatic nerve, the pterygopalatine nerves, and the PSA nerve.
  • #33: Vision is single as long as eyes look above the horizontal plane
  • #52: Vision is single as long as eyes look above the horizontal plane
  • #53: Vision is single as long as eyes look above the horizontal plane