The anatomy of the nerve supply of the head and neck has many significant applications in maxillofacial surgery. Understanding these important anatomic relations- variations enables surgeons to perform the surgical procedures safely. Knowledge of these concepts helps us to recognize the problems and complications as and when they occur and manage them accordingly.
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Nerve supply of head and neck
1.
2. NERVE SUPPLY OF HEAD AND NECK
(Department of Oral & Maxillofacial Surgery)
PRESENTED BY:
Dr. Samarth Johari
(MDS 1st Year)
GUIDED BY:
Dr. Gagan khare
(Professor)
16-11-2018
(Friday)
4. INTRODUCTI
ON
Peripheral nervous system – composed of 12 pairs of cranial nerves &
31 pairs of spinal nerves
Emerging from brain stem
Emerging from spinal cord
Peripheral
Nervous
System
Somati
c
Afferent / Sensory
Efferent / Motor
Viscera
l
Afferent / Sensory
Efferent / Motor
5. Somatic Nerves Defined as those afferent fibers that transmit
stimuli from skin, special sense organs, voluntary muscles, tendons,
ligaments & joints as well as those efferent fibres that activate
voluntary, striated, skeletal musculature
Visceral Nerves Defined as those afferent fibers that transmit
stimuli from viscera as well as those efferent fibres that activate
involuntary, smooth musculature of viscera, cardiac musculature &
secretion of glands
A nerve is a gross conduit
made up of many fibers
A fiber is a long process of a
neuron of specific function
6. Note :
The whole visceral motor outflow is placed in a separate category
k/a Autonomic Nervous System because it acts “automatically”
Major portion of head & neck is supplied by cranial nerves, a minor
portion by upper cervical spinal nerves
Autonomic Nervous System
Sympathetic Parasympathetic
Fibers emerge from
thoracic & upper
lumbar segments of
spinal cord
k/a thoracolumbar
outflow
Fibers emerge directly
from brain stem & from
upper sacral segments
of spinal cord
k/a craniosacral
outflow
7. There are 12 pairs of cranial nerves :
I. Olfactory
II. Optic
III. Occulomotor
IV. Trochlear
V. Trigeminal
VI. Abducent
VII. Facial
VIII.Vestibulocochlear (Statoacoustic / Auditory)
IX. Glossopharyngeal
X. Vagus
XI. Accessory
XII. Hypoglossal
CRANIAL
NERVES
8. Attachment of cranial nerves to the brain :
a. Olfactory & Optic to
forebrain
b. Occulomotor & Trochlear
to mid brain
c. Trigeminal, Abducent,
Facial & Vestibulocohlear
to pons
d. Glossopharyngeal,
Vagus, Accessory,
Hypoglossal to medulla
oblongata
9. NUCLEI OF CRANIAL
NERVES General Somatic Efferent (GSE) Nuclei
Supply skeletal muscle of somatic
origin
1. Oculomotor Nucleus –
• Situated in mid brain at level of
superior colliculus
• Its fibers enter occulomotor
nerve & supplies extrinsic
muscles of eyeball except
lateral rectus & superior oblique
2. Trochlear Nucleus –
• Situated in mid brain at level of
inferior colliculus
10. 3. Abducent Nucleus –
• Situated in lower part of pons
• Supplies only lateral rectus
muscle through abducent nerve
4. Hypoglossal Nucleus –
• Lies in medulla
• Supplies 7 out of 8 muscles of
tongue through hypoglossal
nerve
11. Special Visceral Efferent (SVE)/Branchial Efferent Nuclei-
1. Motor Nucleus of Trigeminal–
• Situated in upper part of pons
• Its fibers enter mandibular nerve & supplies muscles of
mastication
2. Nucleus of Facial Nerve –
• Situated in lower part of pons
• Supplies only muscles innervated by facial nerve
3. Nucleus Ambiguus –
• Lies in medulla
• Supplies stylopharyngeus muscle (through glossopharyngeal
nerve); muscles of soft palate, larynx & pharynx (through vagus &
12.
13. General Somatic Afferent (GSA) Nuclei
All related to trigeminal nerve
1. Main or Superior Sensory Nucleus of
Trigeminal Nerve –
• Lies in upper part of pons
2. Spinal Nucleus of Trigeminal Nerve –
• Descends from main nucleus into
medulla
• Reaches upper 2 segments of
spinal cord
• Parts are :
a) Pars caudalis – receives
impulses of pain, temp. from
forehead
b) Pars interpolaris – receives
14. 3. Mesencephalic Nucleus of
Trigeminal Nerve –
• Extends upwards from main
sensory nucleus into mid
brain
• Receive following fibers :
a) Exteroceptive sensations
(touch, pain, temp.) from
skin of face, through
trigeminal nerve & from
part of skin of auricle
through vagus & facial
nerve
b) Proprioceptive sensations
from muscles of
15. General Visceral Efferent (GVE) Nuclei Give origin to
preganglionic neurons that relay in peripheral autonomic
ganglion postganglionic fibres arising in ganglion supply
smooth muscles or glands
1. Edinger – Westphal Nucleus –
• Lies in mid brain, close to occulomotor nucleus
• Supplies sphincter pupillae & ciliaris muscles via ciliary
ganglion (through occulomotor nerve)
2. Lacrimatory Nucleus –
• Lies in lower pons near salivatory nucleus
• Supplies lacrimal, nasal, palatal & pharyngeal glands via
pterygopalatine ganglion (through facial nerve & its
branch, greater petrosal nerve)
16. 3. Superior Salivatory Nucleus –
• Lies in lower part of pons
• Supplies submandibular,
sublingual salivary glands via
submandibular ganglion
(through facial nerve & its
chorda tympani branch)
4. Inferior Salivatory Nucleus –
• Lies just below superior
nucleus in pons
• Supplies parotid gland via otic
ganglion (through
glossopharyngeal nerve)
17. 5. Dorsal Nucleus of Vagus –
• Extends into medulla
• Gives off fibres that passes through
vagus nerve to be distributed to
thoracic & abdominal viscera
Special Somatic Afferent (SSA) Nucleus :
1. Cochlear Nuclei –
• These are dorsal & ventral
• Receives impulses of hearing
through cochlear nerve
2. Vestibular Nuclei –
• Theses are superior, spinal, medial
& lateral
• Receives fibers from semicircular
18. General Visceral Afferent (GVA) &
Special Visceral Afferent (SVA)
Nucleus :
1. Nucleus of Solitary Tract or
Tractus Solitarius –
• Only nucleus in this category
• Lies in medulla & extends into
both its closed & open parts
• Lower part receives general
visceral sensations :
a. Through glossopharyngeal
nerve from tonsil, pharynx,
posterior part of tongue,
carotid body & carotid sinus
b. Through vagus nerve from
pharynx, larynx, trachea,
19. • Upper part receives
sensations of taste :
a. From anterior 2/3rd
of tongue & palate
except
circumvallate
papillae through
facial nerve in its
superior part
b. From posterior
1/3rd of tongue
through
glossopharyngeal
nerve including
circumvallate
papillae in its
middle part
20. OLFACTORY
NERVE
Transmits sense of smell
Branches arise from sensory
cells of nasal mucosa, enter
cranial cavity as olfactory fila
through openings of
cribriform plate of ethmoid
bone
Enter olfactory bulb singly
Bulb is vestige of olfactory
lobe of macrosmatic
mammals (those animals
21. OPTIC NERVE
Second pair of cranial nerve
Nerve of visual sense
Arise in ganglion cells of
retina
Enters cranial cavity through
optic foramen
22. OCULOMOTOR
NERVE
Contains somatic & parasympathetic
visceral efferent fibres
Somatic fibres responsible for most of
the extrinsic muscles of the eye
Parasympathetic fibres relay in ciliary
ganglion
Postganglionic fibres arising from
ciliary ganglion, enter eyeball & supply
ciliary muscles or muscles of
accommodation & sphincter of pupil
23. TROCHLEAR NERVE
Carries somatic fibres
Supply superior oblique
muscle of eyeball
Passes through superior
orbital fissure
24. TRIGEMINAL NERVE
Consists of greater somatic sensory
& small somatic motor portion
Motor fibres supply masticatory
muscles, tensor palate muscle,
mylohyoid muscle, ant. belly of
digastric & tensor tympani muscle
Sensory fibers except
proprioceptive fibers arise in
semilunar ganglion & supply skin of
entire face & mucous membrane of
cranial viscera except pharynx &
base of tongue
25. Course of motor root & sensory root of trigeminal nerve :
26. Opthalmic Division :
• 1st branch of Vth cranial nerve
• Purely sensory & smallest of 3
divisions
• Supplies eyeball, conjunctiva,
lacrimal gland, parts of mucous
membrane of nose & paranasal
sinuses & skin of forehead,
eyelids & nose
• Divides into 3 main branches
just before passing through
superior orbital fissure –
1. Nasocilliary
2. Frontal
30. Maxillary Division :
• Arise from middle of trigeminal ganglion
• purely sensory
• Exits cranium through foramen rotundum (located in greater wing of
sphenoid bone)
• Supplies –
1. Skin –
a. Middle portion of face b. Lower eyelid
c. Side of nose d. Upper lip
2. Mucous membrane –
a. Nasopharynx b. Maxillary sinus
c. Soft palate d. Tonsil
e. Hard palate
31.
32. Branches of
Maxillary
Division
Branches within
Cranium
Branches within
Pterygopalatine
Fossa
Branches within
Infraorbital
Canal
Branches on
Face
• Middle
Meningeal
Nerve –
travels with
middle
meningeal
artery to
provide
sensory
innervation
to duramater
• Zygomatic
Nerve
• Pterygopalatin
e Nerve
• Posterior
Superior
Alveolar Nerve
• Middle
Superior
Alveolar
• Anterior
Superior
Alveolar
• Inferior
Palpebral
• External Nasal
• Superior Labial
33.
34. Branches within
Pterygopalatine Fossa
Zygomatic
Nerve
Pterygopalatine Nerve
Posterior Superior
Alveolar Nerve
• Zygomaticote
mporal –
sensory to
skin on side
of forehead
• Zygomaticofa
cial – supplies
skin on
prominence
of cheek
• Orbital branch – supplies
periosteum of orbit
• Nasal branch – important
branch is nasopalatine nerve
which supplies ant. part of
nasal septum & floor of nose
& enters incisive foramen to
supply premaxillary region
• Palatine Branch – branches
off into greater palatine &
lesser palatine
• Pharyngeal Branch – mucous
membrane of nasal part of
• Branches off in
infratemporal fossa
• Supplies alveoli,
periodontal
ligaments, pulpal
tissues of maxillary
3rd, 2nd &1st molar
(except mesiobuccal
root of 1st molar in
28% cases)
35. Branches within Infraorbital Canal
Middle Superior Alveolar Anterior Superior Alveolar
• Supplies mesiobuccal root of
maxillary 1st molar, buccal
soft tissue, periodontal
ligaments, premolars
• Branches off 6-10 mm ahead
of middle superior alveolar
nerve
• Provides pulpal innervation
to central incisors, lateral
incisors, canine periodontal
ligaments & alveolar bone
36. Branches on Face
Inferior
Palpabral
External Nasal Superior Labial
• Supplies skin
of lower
eyelid
• Supplies skin
on lateral
aspect of
nose
• Supplies skin
& mucous
membrane of
upper lip
37. Mandibular Division :
• Largest branch of trigeminal nerve
• Mixed nerve with 2 roots –
1. Large sensory – originates at inferior angle of trigeminal ganglion
2. Smaller motor – arise in motor cells located in pons & medulla
oblongata
• 2 roots emerge from cranium separately through foramen ovale
• Motor lies medial to sensory
• Unite outside skull to form main trunk of 3rd division
• Remains united for 2-3 mm & then divides into small anterior part &
large posterior part
38. Mandibular nerve supplies :
1. Sensory root -
a. Skin of temporal region, auricular region, external auditory
meatus, cheek, lower lip, chin
b. Mucous membrane of cheek, tongue (anterior 2/3rd), mastoid
cells
c. Mandibular teeth & PDL
d. Alveolar bone of mandible
e. TMJ
f. Parotid gland
2. Motor root –
a. Masticatory muscles
b. Mylohyoid muscle
c. Anterior belly of digastric
d. Tensor tympani
e. Tensor vili palatini
39.
40. Branches of
Mandibular Nerve
From undivided part From anterior division
From posterior
division
• Branches off into-
nervus spinosus or
meningel branch of
V3 (re-enters
cranium through
foramen spinosum
along with middle
meningeal artery t
supply duramater &
mastoid air cells),
nerve to medial
pterygoid (motor to
medial pterygoid
musle & gives small
branches motor to
tensor veli palatine
• Motor to
masticatory
muscles &
sensory to
mucous
membrane of
cheek & buccal
mucous
membrane of
mandibular
molars
• Branches off
into- buccal,
deep temporal,
masseter,
lateral
• Branches off
into-
auriculotempor
al, lingual,
inferior
alveolar,
mylohyoid,
mental &
incisive nerves
41.
42. ABDUCENT
NERVE
Sixth pair of cranial nerve
Consists of somatic motor
fibers
Supplies lateral rectus
muscle of the eyeball
Passes through the superior
orbital fissure
43. FACIAL NERVE
Consists of 2 nerves – facial nerve proper & intermediate nerve
Consists of somatized motor fibers destined for
muscles of facial expressions, including occipital,
auricular, platysma, posterior belly of digastric &
stapedius & stylohyoid muscles
Contains proprioceptive sensory fibers (for deep sensitivity of face, taste
sensations in anterior 2/3rd of tongue & on palate) & preganglionic
visceral efferent fibers (for lacrimal gland, sublingual; submandibular
salivary glands & smaller glands of oral cavity
Both the nerves emerge from brain at pontocerebral angle /
pontomedullary junction in front of & medial to statoacoustic nerve
45. Branches of facial nerve :
1. Within the facial canal –
a) Greater petrossal
b) Nerve to stapedius
c) Chorda tympani
2. After emrging from stylomastoid foramen –
a) Posterior auricular
b) Nerve to posterior belly of digastric
3. Terminal branches –
a) Temporal (supplies frontal muscles, superior part of orbicularis
oculi, corrugator, slender of nose)
b) Zygomatic (supplies inferior part of orbicularis oculi)
c) Buccal (upper buccal – muscles of upper lip & nose; lower buccal
– buccinators & risorius muscle)
d) Marginal mandibular (supplies muscles of lower lip & mental
muscle)
e) Deep cervical (supplies platysma muscle)
46. AUDITORY NERVE
Also known as statoacoustic nerve
& vestibulocochlear nerve
Combination of vestibular & cochlear
nerves
arises from
cochlea of
labyrinth &
transmits
sensation of
hearing
Arises from semicircular canals,
47. GLOSSOPHARYNGEAL
NERVE
Emerges from lateral surface of
medulla oblongata & passes in
front of vagus nerve through
jugular foramen
Contains motor fibers
Motor supply to stylopharyngeus
muscle & participates with vagus
in supplying constrictors of
pharynx & palatopharyngeus
muscle
Sensory supply to parts of tonsil,
48. VAGUS NERVE
Largest parasympathetic visceral
nerve
Contains both visceral & somatic
fibers
Sensory fibers arise from
superior/jugular ganglion &
inferior/nodose ganglion & supply
skin behind ear & lining of part of
external acoustic meatus
Motor supply to pharyngeal &
laryngeal muscles
49. ACCESSORY NERVE
Consists of cranial & spinal portion &
former is functionally a part of vagus
nerve & in periphery, its fibers are
indistinguishable from that of vagus
Spinal part arises from upper 5 or 6
cervical segments of spinal cord,
enters cranium through foramen
magnum & join cranial accessory
Exits cranium through jugular
foramen along with glossopharyngeal
& vagus nerve
50. HYPOGLOSSAL
NERVE
Twelfth cranial nerve
Arises from medulla
oblongata
Leaves the skull
through hypoglossal
canal
Motor supply to all
intrinsic & extrinsic
muscles of tongue
except palatoglossus
51. Joined by nerve that arises from
the loop between 1st & 2nd
cervical nerves
Most of these fibers get detached
from hypoglossal nerve as it
reaches between internal &
external carotid artey &
constitutes the superior branch
of the ansa cervicalis
Joind by branches from 2nd & 3rd
cervical nerves (inferior branch of
ansa cervicalis)
From this loop branches off to
supply omohyoid, sternothyroid,
Cervical fibers that do not get detached continue in the sheath of
hypoglossal nerve & branches off into nerve for thyrohyoid &
52. The anatomy of the nerve supply of
the head and neck has many
significant applications in
maxillofacial surgery. Understanding
these important anatomic relations-
variations enables surgeons to
perform the surgical procedures
safely. Knowledge of these concepts
helps us to recognize the problems
and complications as and when they
occur and manage them accordingly.
CONCLUSION
53. Oral Anatomy by Sicher and DuBrul
Gray’s Anatomy
Oral & Maxillofacial Surgery by Fonseca
Atlas of Operative Maxillofacial Trauma Surgery by Springer
Textbook of Human Anatomy by B.D.Chaurasia, Vol.3
Textbook of Human Embryology by Inderbir Singh
REFERENCES