CRANIAL NERVES

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CRANIAL NERVES

• DR VINIT K ASHOK
• ADJUNCT FACULTY

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CRANIAL NERVES

• NERVES COMING OUT/ GOING INTO THE BRAIN
• TOTAL -12 NUMBERED IN ROMAN NUMERICALS( I-XII)
• CARRY IMPULSES TO AND FROM THE BRAIN
• EXIT OR ENTER THE SKULL THROUGH OPENINGS IN THE
  SKULL
• I AND 11 ARE ATTACHED TO THE FOREBRAIN
• III TO XII ARE ATTACHED TO THE BAIN STEM
• ALL SUPPLY THE STRUCTURES OF THE HAED AND NECK
  EXCEPT THE X( VAGUS) ----VAGABOND -----WANDERS TO
  THE ABDOMEN

• I OLFACTORY
• II- OPTIC
• III-OCCULOMOTOR
• IV-TROCHLEAR
• V-TRIGEMINAL( 3 DIVISIONS)
• VI ABDUCENS
• VII-FACIAL
• VIII-VESTIBULOCOCHLEAR
• IX-GLOSSOPHARYNGEAL
• X-VAGUS
• XI-ACCESSORY
• XII-HYPOGLOSSAL
• OH OH OH TO TOUCH AND FEELVERY GOOD VELVET AH

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FORAMINA /OPENINGS FOR THE CRANIAL NERVES

• I OLFACTORY FORAMINA
• II-OPTIC FORAMEN
• III- SUPERIOR ORBITAL FISSURE
• IV-SUPERIOR ORBITAL FISSURE
• V- 3 DIVISIONS
• A) OPTHALMIC- SUPERIOR ORBITAL FISSURE
• B) MAXIALLRY-FORAMEN ROTUNDUM
• C) MANDIBULAR- FORAMEN OVALE
• VI-INFERIOR ORBITAL FISSURE
• VII- ENTERS THE INT ACCOUSTIC MEATUS---- EXITS
  THE SKULL THROUGH THE STYLOMASTOID FORAMEN
• VIII- INT ACCOUSTIC MEATUS
• IX-JUGULAR FORAMEN
• X-JUGULAR FORAMEN
• XI- JUGULR FORAMEN
• XII-HYPOGLOSSAL CANAL

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• I-OLFACTORY NERVE-SENSORY NERVES OF SMELL
• II - OPTIC NERVE-SENSORY NERVE OF VISION
• III- OCCULOMOTOR-( EYE MOVER)-INNERVATES 4
  EXTRINSIC MUSCLES OF THE EYEBALL
• 1V- TROCLEAR NERVE- ( MEANS PULLEY) SUPPLIES THE
  SUPERIOR OBLIQUE MUSCLE OF THE EYEBALL
• V-TRIGEMINAL ( 3 FOLD) THIS NERVE HAS 3
  BRANCHES. SENSORY INNERVATION TO THE FACE AND
  MOTOR TO MUSCLES THAT HELP US CHEW( MASTICATE)
• VI-ABDUCENS NERVE- IT SUPPLIES THE MUSCLE OF THE
  EYEBALL THAT ABDUCTS THE EYE( LATERAL RECTUS)
• VII-FACIAL NERVE-INNERVATES MUSCLES OF FACIAL
  EXPRESSION
• VIII-VESTIBULOCOCHLEAR-SENSORY NERVE OF HEARING
  AND EQUILIBRIUM
• IX-GLOSSOPHARYNGEAL NERVE-( MEANS TONGUE AND
  PHARYNX), STRUCTURES THIS NERVE INNERVATES
• X-VAGUS ( WANDERER)-INNERVATES THE STRUCTURES IN
  THE THORAX AND ABDOMEN
• XI-ACCESSORY- ( ACCESSORY TO THE VAGUS)-SUPPLIES
  THE TRAPEZIUS AND STERNOCLEIDOMASTOID
• XII-HYPOGLOSSAL( BELOW THE TONGUE)-RUNS INFERIOR
  TO THE TONGUE AND SUPPLIES THE TONGUE MUSCLES

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SENSORY/MOTOR NERVE

• CRANIAL NERVES --- PURELY SENSORY / MOTOR / MIXED
• SENSORY NERVE- RECEPTORS---- GENARAL SENSATIONS(
  TOUCH, PAIN TEMP,PRESSURE,) SPECIAL ---
  SMELL,VISION, HEARING, EQUILIBRIUM.---CRANIAL
  NERVEBRAIN.( I, II AND VIII) ( AFFERENT
  IMPULSES)
• MOTOR NERVE-IMPULSE FROM THE BRAIN----CRANIAL
  NERVE ----ACTION----( MUSCLE/GLAND)----EFFERENT
  IMPULSES( III,IV,VI,XI AND XII)
• MIXED ( BOTH TYPE OF FIBRES)

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NERVES

• MOTOR ( TYPES)
• 1. VISCERAL MOTOR
• ( MOTOR NERVE SUPPLY TO THE VISCERA AND GLANDS)
• 2. BRANCHIAL MOTOR
• MOTOR NERVE SUPPLY OF THE BRANCHIAL ARCH
  MUSCULATURE
• 3. SOMATIC MOTOR
• MOTOR SUPPLY TO ALL OTHER SKELETAL MUSCLES

• SENSORY
• 1.VISCERAL SENSORY
• SPECIALTASTE
• GENERAL---VISCERAPAIN,TOUCH,PRESSURE,
• TEMP
• 2.SOMATIC SENSORY
• SPECIAL- SMELL, VISION HEARING
• GENERALTOCH ,PAIN PRESSURE FROM THE LIMBS, BODY
  WALL

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CRANIAL NERVES WITH PARASYMPATHETIC FIBRES

• III- OCCULOMOTOR
• -1. CONTRICTOR PUPILLAE
• 2. CILIARIS- CHANGES THE SHAPE OF THE LENS
• VII- FACIAL
• TEAR , NASAL AND PALTINE GLANDS
• SUBMANDIBULAR AND SUBLINGUAL GLANDS
• IX- GLOSSOPHARYNGEAL
• PAROTID GLAND
• X- VAGUS
• 1. THORACIC AND ABDOMINAL VISCERA

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SPECIAL SENSESVISION

• ORGAN- EYE
• 1/6 TH SEEN OUTSIDE REST INSIDE---ORBITAL CAVITY(
  FAT)
• ACCESSORY STRUCTURES
• Eyebrows
• EYELIDS
• CONJUNCTIVA
• LACRIMAL APPARATUS
• EXTRINSIC MUSCLES

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EXTERNAL ANATOMY
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CLINICAL CONDITIONS

• CHALAZION-INFECTION OF THE TARSAL GALNDS(
  MEBOMIAN )
• STY- INFECTION OF THE CIALIARY GLANDS
• CONJUNCTIVITIS- ( PINK EYE) ---INFLAMMANTION OF ?

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LACRIMAL APPARATUS
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EXTRINSIC MUSCLES OF THE EYE
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EXTRINSIC MUSCLES
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ANATOMY OF THE EYEBALL

• FUNCTIONS
• A) PROTECTS AND SUPPORTS THE DELICATE
  PHOTORECEPTOR CELLS
• B)GATHERS,FOCUSES AND PROCESSES LIGHT INTO
  PRECISE IMAGES
• PARTS
• ANTERIOR POLE
• POSTERIOR POLE
• TUNICS( EXTERNAL WALL)
• HUMORS( FLUID ) INSIDE
• LENS

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• FIBROUS TUNIC(OUTERMOST)
• - DENSE CONNECTIVE TISSUE( PROTECTION, MUSCLES
  INSERTED)
• POSTERIOR 5/6TH ( SCLERA) WHITE OF THE EYE
• ANTERIOR 1/6TH TRANSPARENT CORNEA( AVASCULAR)
• LIMBUS
• SCLERAL VENOUS SINUS( DRAINS AQUEOUS HUMOR)

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• VASCULAR TUNIC( MIDDLE)
• CHOROID, CILIARY BODT AND IRIS
• CHOROID--- VASCULAR , PIGMENTED( LIGHT IS NOT
  SCATTERED)
• CILIARY BODY---CILIARY MUSCLE----CIRIARY
  PROCESSES
• IRIS---( COLOR OF THE EYE)----CENTRAL OPENING
  ---PUPIL

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INTERNAL ANATOMY
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SAGITTAL SECTION INTERNAL ANATOMY
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RETINA

• SENSORY(
• INNERMOST)
• RETINA( MOST IMPORTANT)
• OUTER ---PIGMENTED( PREVENTS LIGHT SCATTERING)
• INNER---NEURAL ( LIGHT SENSITIVE PHOTORECEPTOR
  CELLS, BIPOLAR AND GANLION CELLS
• PHOTORECTORS----RODS/ CONES

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OPTIC NERVE
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EAR

• RECEPTOR ORGAN FOR HEARING AND EQUILIBRIUM
• OUTER/ MIDDLE EAR------HEARING
• INNER EAR----HEARING/EQUILIBRIUM
• OUTER EAR
• PINNA---AURICLE( ELASTIC CARTILGE,EXCEPTLOBULE)
• EXT ACOUSTIC MEATUS2.5MM TUBE---AURICLE----EAR
  DRUM( EAR WAX)
• EAR DRUM---TYMPANIC MEMBRANE---BOUNDARY BETWEEN
  OUTER AND MIDDLE EAR

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MIDDLE EAR

• ALSO CALLED TYMPANIC CAVITY
• AIR FILLED / INSIDE THE PETROUS TEMPORAL
• LATERAL BOUNDARYTYMPANIC MEMBRANE, MEDIAL
  BOUNDARYBONE SEPERATING IT FROM THE MIDDLE EAR
• SUPERIOR BOUNDARY-PETROUS TEMPORAL
• POSTERIOR WALLMASTOIOID ANTRUM
• INFERIOR BOUNDARY----BONE/IJV
• ANTERIOR BOUNDARY-BEHIND ICA
• MEDIAL WALL---OVAL AND ROUND WINDOW
• PHARYNGOTYMPANIC TUBE CONNECTS IT TO THE
  NASOPHARYNX
• OSSICLE ARE PRESENT
• 2 MUSCLES- STAPEDIUS/ TENSOR TYMPANI

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INNER EAR

• ALSO CALLED LABYRINTH( MAZE LIKE)
• BONY LABYRINTH/MEMBRANOUS LABYRINTH
• BONY---PETROUS TEMPORAL----SEMICIRCULAR CANALS,
  VESTIBULE AND COCHLEA----PERILYMPH
• MEMBRANOUS SMICIRCULAR DUCTS,UTRICLE, SACCULE,
  COCHLEAR DUCT

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