NERVE SUPPLY OF HEAD & NECK Dr. Amit T. Suryawanshi Oral and Maxillofacial Surgeon Pune, India Contact details : Email ID - [email protected] Mobile No - 9405622455
May 24, 2015
NERVE SUPPLY OF
HEAD & NECK
Dr. Amit T. SuryawanshiOral and Maxillofacial Surgeon
Pune, India
Contact details :Email ID - [email protected]
Mobile No - 9405622455
CONTENTS
BASIC NEUROANATOMY
Origin of nervous system
Divisions of nervous system
Cranial nerves
NEUROANATOMY
• Sensory stimuli
Sensory Nerves
• Correlation• Coordination
BRAIN• Muscles• Glands
etc.
Motor Nerves
Basic organization of the nervous system
The nervous system is an organ system containing a network of specialized cells called neurons that transmit signals between different parts of the body. coordinate the actions .
The nervous system consists of two parts,
1. Central nervous system
2. Peripheral nervous system.
The Nervous system
Origin Of Nervous System
NERVOUS SYSTEM
EMBRYONIC
ECTODERM
NEURAL PLATE
NEURAL CREST CELLS
PNS ANS
NEURAL TUBE
CNS
Origin Of Nervous System
Divisions of Nervous system Nervousrsystem
CENTRAL NERVOUS SYSTEM
Brain & Spinal cord
PERIPHERAL NERVOUS SYSTEM
Cranial & Spinal nerves and their associated ganglia
Autonomic Nervous system
Somatic Nervous system
SensoryDivisions
Motor Divisions
Parasympathetic N. system
Sympathetic N. system
Enteric N. System
Basic Functions of the Nervous System
1. Sensation- Events or changes occurring inside and outside the
body. Such changes are known as STIMULI and the cells that monitor them are RECEPTORS.
2. Integration- The parallel processing and interpretation of sensory
information to determine the appropriate response.
3. Reaction- Motor output.
The activation of muscles or glands (typically via the release of neurotransmitters (NTs))
1. Central Nervous System –
Organization of the Nervous System
2. Peripheral Nervous System - The nervous system
outside the brain and spinal cord
Consists of:31 Spinal nerves
- Carry information to and from the spinal cord.
12 Cranial nerves - Carry information
to and from the brain.
- Ganglia
Divisions of Nervous System :
The brain the spinal cord
The Main center of integration and control
Divisions of Nervous System -
Receives sensory input from the spinal cord as well as from its own nerves (e.g., Cranial nerves )
Devotes most of its volume (and computational power) to processing its various sensory inputs and initiating appropriate and coordinated — motor outputs.
1. Central Nervous System
The brain -
Spinal Cord -
- Conducts sensory information from the peripheral nervous system (both somatic and autonomic ) to the brain
- Conducts motor information from the brain to our various effectors
-skeletal muscles-cardiac muscle-smooth muscle-glands
Peripheral Nervous SystemResponsible for communication between the CNS and the rest of the body . It is divided into:
Sensory division ( Afferent division ) Motor division ( Efferent division )
Sensory division ( Afferent division ) –
- Conducts impulses from RECEPTORS to the CNS
- Informs the CNS about the state of the body - ( interior and exterior )
- Sensory nerve fibers can be ,
SOMATIC - Conduct impulses from skin, skeletal muscles and Joints to CNS
VISCERAL –Conduct impulses from smooth muscles, cardiac muscles, and glands (Internal organs) to CNS.
Motor Division ( Efferent Division ) -
It is divided into:
Somatic nervous system - VOLUNTARY (generally) Conducts impulses from the CNS to skin , skeletal
muscles , joints
Autonomic nervous system - INVOLUNTARY (generally) Conducts impulses from the CNS to smooth
muscles, cardiac muscles, and glands (Internal organs )
Autonomic Nervous System-Divided into:
Sympathetic Nervous System - “Fight or Flight”
Parasympathetic Nervous System - “Rest and Digest”
These 2 systems are antagonistic.
The sympathetic nervous system aids in the control of most of the body's internal organs.
Stress — as in the flight-or-fight response.
Sympathetic Nervous System -
“Rest and Digest”Phenomenon
- generally works to promote maintenance of the body at rest.
Parasympathetic Nervous System -
The enteric nervous system is a meshwork of nerve fibers that innervate the viscera
Enteric Nervous System
Gastrointestinal tract, Pancreas Gall bladder.
NEURON-
Neuron (nerve cell)–It is basic structural
and functional unit of the nervous system.
Types of NEURON
NEUROANATOMYNeuron consists of : a cell body
containing nucleus – the
Neuronal soma.
Multiple number of processes -
dendrites and axons
NEUROANATOMY
Dendrites conduct information towards the cell body
Axons conduct impulses away from cell body
Function Of Neurons -
Neurons produce andconduct nerve impulses.
A synapse is the
site of functional contact between axon and another neuron or organ.
Neurotransmitters
are released at synapses and they help in transmission of impulses.
Synapse and Neurotransmitters
Afferent neurons - carry sensations of touch , pain,
temperature and pressure. Therefore they are called as sensory fibers .
Efferent neurons - carry impulses away from the central
nervous system.
NUCLEUS - is a compact group of nerve cell bodies of similar form and function, located inside the CNS.
GANGLION – is a similar group of nerve cell bodies located outside the CNS.
NUCLEUS & GANGLION
NEUROANATOMY
The PNS has three main types of nerves:
1. Cranial Nerves 2. Spinal Nerves and3. Autonomic Nerves
All cranial nerves are attached to the brainstem, except for cranial nerve XI, Accessory Nerve. which is attached to the spinal cord.
All spinal nerves are attached to the spinal cord.
All spinal nerves have dorsal and ventral roots.
spinal nerves -
The autonomic nerves run through the roots of cranial or spinal nerves to ganglia or autonomic plexuses in the walls of the viscera (smooth muscles and glands)
They also return sensory impulses to CNS from
sensory receptors in viscera.
Cranial Nerves I . Olfactory Nerve II . Optic Nerve III. Oculomotor Nerve IV. Trochlear Nerve V. Trigeminal Nerve VI. Abducent NerveVII. Facial Nerve VIII. Vestibulocochlear Or Auditory N.IX. Glossopharyngeal NerveX. Vagus Nerve XI. Accessory Nerve XII. Hypoglossal Nerve
Entirely sensory in function.
Arises from olfactory receptor nerve cells in the
mucous membrane of nasal cavity.
Bundles of these nerve fibers pass through
openings of cribriform plate of ethmoid bone
and synapse in the olfactory bulb.
OLFACTORY NERVE
From olfactory bulb ,the second order nerve fibers pass through the olfactory tract to the olfactory cortex in cerebrum.
The olfactory cortex in cerebrum is responsible for appreciation of olfactory sensations. i.e. Sensation of Smell.
• The Optic Nerve passes from the eyeball through the optic canal into the middle cranial fossa .
OPTIC NERVE
Entirely sensory in function.
The two optic nerves join below the base of the diencephalon to form optic chiasma and then divides into two optic tracts
Optic nerve transmits visual information from light-sensitive receptors on the retina of the eye to the brain for analysis, interpretation .
Entirely motor in function.
Oculomotor nerve nuclei: Two nuclei –
1. the main motor nucleus situated in midbrain.
2. the parasympathetic nucleus situated posterior to the motor nucleus
OCULOMOTOR NERVE
Course of occulomotor nerve : The occulomotor nerve emerges from the
midbrain- then continues in the middle cranial fossa in the lateral wall of cavernous sinus.
Here it divides into superior and inferior ramus which enter the orbital cavity through superior orbital fissure.
The occulomotor nerve supplies parasympathetic innervation to the intraocular muscles.
And somatic innervation to the extraocular muscles.
Parasympathetic fibers synapse in ciliary ganglion.
The occulomtor nerve supplies the following extrinsic muscles of eye :
1. Levator palpebrae superioris
2. Superior, medial and inferior rectus
3. Inferior oblique
The oculomotor nerve is responsible for:
1. Lifting the upper eyelid.
2. Turning the eye upward, downward and medially.
3. Constricting the pupil and accomodating the eye.
Entirely motor in function.
Trochlear nerve nucleus –
Situated in midbrain
and lies inferior to the
Oculomotor nucleus.
TROCHLEAR NERVE
Course of trochlear nerve : Leaves the brainstem and immediately
decussates with the nerve of opposite side . It passes through the middle cranial fossa in the lateral wall of cavernous sinus and enters orbit through superior orbital fissure.
The nerve supplies superior oblique musle of eyeball.
It assists in turning eye downward and laterally.
Course & relations
Anterior aspect of Pons ( sensory and Motor Root )
Middle Cranial Fossa
Meckel’s cavity ( Trigeminal Ganglion)
Superior orbital fissure
Ist DivisionOphthalmic
IInd Division Maxillary
Foramen Rotundum
IIIrd Division Mandibular
Foramen Ovale
TRIGEMINAL NERVE
OPHTHALMIC DIVISION
Course & relations
Trigeminal Ganglion
Middle Cranial Fossa
Lateral wall of Cavernous Sinus
Superior Orbital Fissure
Orbit
-Lacrimal -Frontal -Nasociliary
OPHTHALMIC DIVISION
LACRIMAL NERVE
Superior Orbital Fissure
Lateral wall of Orbit
Above the Lateral Rectus muscle
Lacrimal Gland
Course & Relations
Course & relations
Superior Orbital Fissure
Rim of Orbit
Levator Palpebrae Superioris
Supra-orbital Supra-trochlear
Supra-orbital Foramen
Frontal nerve
NASO-CILIARY NERVECourse & relations
Superior Orbital Fissure
Within common tendinous ring of Recti
Optic Nerve
Below superior rectus & superior oblique
Medial orbital wall
AnteriorEthmoidal
PosteriorEthmoidal
LongCiliary
Infra-trochlear
External nasal Internal nasal
MAXILLARY NERVE
Gasserion Ganglion
Foramen Rotundum
Pterygopalatine Fossa
Infra –Orbital Canal
Infra –Orbital Foramen
Face
Middle Meningeal N.
-Pterigopalatine N-Posterior superior alveolar N-Zygomatic N
-Inferior palpebral-External nasal-Superior labial
Anterior superior alveolar N Middle superior alveolar N
- Branches and Course -
MAXILLARY DIVISION
Maxillary Nerve Branches (within pterigopalatine fossa )
Zygomatic N
Inferior OrbitalFissure
Zygomatico-facial
Supplies-Facial prominenceOf cheek
Supplies-Skin of temple
Zygomatico-temporal
Pterygopalatine Nerves
Orbital Nasal Palatine
Continued -
Nasopalatine N. Greater palatine n.
middle palatine n.
posteriorpalatine n.
Posterior superior Alveolar N.
PosteriorHard palate
Soft palate,Tonsil,uvula
Softpalate
Maxillary molars , buccal Mucosa in molar region
Maxillary Nerve Branches ( within infraorbital canal )
Middle superior alveolar nerve
Anterior superior alveolar nerve
Supplies-Maxillary Incisors,canine
Supplies –Maxillary premolars
Maxillary Nerve Branches ( on the face )
InferiorPalpebralbranches
External nasal branches
Superior labial branches
LowerEyelid
UpperLip,cheekSide of
Nose
- Superior dental plexus -
MANDIBULAR NERVE Course & Relations
Gasserion Ganglion
Motor rootForamen Ovale
Maintrunk
Nerve to medial pterygoid
Anteriordivision
Posteriordivision
Buccal
Nerve to MasseterNerve To TemporalisNerve to Lateral Pterygoid
Auriculo-temporal
Mylohyoid Nerve
SuperficialtemporalCutaneous
Mental
Incisive
Lingual
Inferior alveolar
sensory root
Nervous spinosus-
ABDUCENT NERVE
Entirely motor and supplies the lateral rectus
muscle of the eyeball.
Abducent nerve nucleus : situated in pons
ABDUCENT NERVE -
Course of abducent nerve : The nerve fibers emerge from the pons from the groove between pons and medulla
oblongata.
It passes through cavernous sinus and lies below
the internal carotid artery.
The nerve enters the orbit through superior orbital
fissure.
Abducent nerve :
FACIAL NERVE
Course and Branches of Facial Nerve
PONS
INTERNAL AUDITORY MEATUS
PETROUS PART OF TEMPORAL BONE
FACIAL CANAL
STYLOMASTOID FORAMEN
Motor root
PAROTID GLAND
FACIAL MUSCLES
(GENICULATE GANGLION )
Medulla oblongata
PAROTID PLEXUS
GREATER PETROSALNERVE TO STAPEDIUSCHORDA TYMPANI
POSTERIOR AURICULARN . POST. BELLY OF DIGASTRICN . STYLOHYOID
-Course-
Sensory root
• Greater petrosal nerve - - provides motor innervation to lacrimal gland , mucosal glands of the nose, palate, and pharynx. - carries special sensory taste fibers from the palate .
• Nerve to stapedius - provides motor innervation for stapedius muscle in middle ear
• Chorda tympani - carries special sensory taste fibers from the anterior 2/3rd of the tongue.
Outside skull - (Distal to stylomastoid foramen)
• Posterior auricular nerve -
• Nerve to Posterior belly of Digastric • Nerve to Stylohyoid muscle .
Facial nerve enters parotid gland and forms parotid plexus
Parotid Plexus
• Its main function is motor control of most of the muscles of facial expression.
• The facial nerve also supplies parasympathetic fibers to the submandibular gland and sublingual glands via chorda tympani
Functions -
-It is Sensory nerve .-It consists of two roots
- Vestibular root- Cochlear root
Vestibulocochlear Nerve Or Auditory Nerve
Course -
Vestibular root transmits impulses from vestibular apparatus ( Balance )
Cochlear root transmits impulses from auditory apparatus (Sound )
Vestibular root --
Cochlear root --
• Auditory nerve transmits sound and equilibrium (balance) information from the Internal ear to the Brain .
Functions -
Glossopharyngeal nerve
It originates from medulla oblongata
Inferior salivatory nucleus Nucleus ambiguusNucleus of solitory tract
Nuclei -
Glossopharyngeal nerve
Glossopharyngeal nerve
Superior GanglionInferior Ganglion
• Branches -
• Tympanic nerve (s)
• Branch to carotid sinus (s)
• Branch to Stylopharyngeus muscle (m)
• Tonsillar branches (s)
Lingual Branches • (S)
• Pharyngeal branches (m)
• Tympanic nerve -Sensory fibers supply the middle ear.Secretory fibers supply the parotid gland
• Nerve to carotid sinus -
Receives sensory information from ‘ Chemoreceptors in Carotid body . Baroreceptors in carotid sinus .
• Nerve to Stylopharyngeus muscle
• Tonsillar branches (s)
Lingual Branches -
Receives sensory information from posterior 1/3rd of the tongue.
• Pharyngeal branches -
Innervate constrictor muscles of the pharynx.
Vagus nerve
Nuclei -
-Nucleus ambiguus -Nucleus of solitory tract ( superior part & inferior part )
It originates from medulla oblongata
COURSE OF VAGUS NERVE
VAGUS NERVE (MIXED)
Superior Ganglion - Meningeal nerve - Auricular nerve
Inferior Ganglion - Pharyngeal branches - Superior laryngeal nerve - external laryngeal n. - internal laryngeal n. - Recurrent laryngeal - Cervical Carotid branches -Anterior esophageal plexus -gastric, celiac, hepatic branches
BRANCHES -
• Cricothyroid muscle
Levator veli palatini muscle
• Salpingopharyngeus muscle
• Palatoglossus muscle
• Palatopharyngeus muscle
• Superior, middle and
inferior pharyngeal constrictors
• Muscles of the larynx (speech)
• It supplies -
Accessory nerve (motor)Course -
Cranial root –
Cranial root joins Vagus nerve and innervates - all laryngeal muscles except cricothyroid
Spinal root -Spinal root innervates -Trapezius -Sternocleidomastoid
Hypoglossal nerve (motor)
Medulla Oblongata(Hypoglossal Nucleus)
Hypoglossal Canal Behind Vagus Nerve Between IJV & ICA
Posterior Belly of Digastric
Tongue(Intrinsic and extrinsic muscles)
COURSE & RELATIONS
Extrinsic muscles Genioglossus Hyoglossus Styloglossus Intrinsic muscles Superior longitudinal Inferior longitudinal Verticalis Transversus
It supplies --
Except Palatoglossus which is supplied by cranial part of accessory nerve
ReferencesGray’s AnatomyOral and maxillofacial surgery – LaskinAtlas of Anatomy - Anne Gilroy LA – Malamed Guyton (physiology )Ganong (physiology )Internet
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