CRANIAL NERVES

DR VINIT K ASHOK

ADJUNCT FACULTY

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

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

• 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

SENSORY/MOTOR NERVE• CRANIAL NERVES --- PURELY

SENSORY / MOTOR / MIXED SENSORY NERVE- RECEPTORS----

GENARAL SENSATIONS( TOUCH, PAIN TEMP,PRESSURE,) SPECIAL --- SMELL,VISION, HEARING, EQUILIBRIUM.---CRANIAL NERVE—BRAIN.( 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)

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

A) SPECIAL—TASTE

B) GENERAL---VISCERA—PAIN,TOUCH,PRESSURE,

TEMP

2.SOMATIC SENSORY

A) SPECIAL- SMELL, VISION HEARING

B) GENERAL—TOCH ,PAIN PRESSURE FROM THE LIMBS, BODY WALL

CRANIAL NERVES WITH PARASYMPATHETIC FIBRES

• III- OCCULOMOTOR

-1. CONTRICTOR PUPILLAE

2. CILIARIS- CHANGES THE SHAPE OF THE LENS

• VII- FACIAL

1. TEAR , NASAL AND PALTINE GLANDS

2. SUBMANDIBULAR AND SUBLINGUAL GLANDS• IX- GLOSSOPHARYNGEAL

1. PAROTID GLAND

X- VAGUS

1. THORACIC AND ABDOMINAL VISCERA

SPECIAL SENSESVISION

• ORGAN- EYE

• 1/6 TH SEEN OUTSIDE REST INSIDE---ORBITAL CAVITY( FAT)

• ACCESSORY STRUCTURES

1. Eyebrows

2. EYELIDS

3. CONJUNCTIVA

4. LACRIMAL APPARATUS

5. EXTRINSIC MUSCLES

EXTERNAL ANATOMY

CLINICAL CONDITIONS• CHALAZION-INFECTION OF THE

TARSAL GALNDS( MEBOMIAN )• STY- INFECTION OF THE CIALIARY

GLANDS• CONJUNCTIVITIS- ( PINK EYE) ---

INFLAMMANTION OF ?

LACRIMAL APPARATUS

EXTRINSIC MUSCLES OF THE EYE

EXTRINSIC MUSCLES

ANATOMY OF THE EYEBALL• FUNCTIONS

• A) PROTECTS AND SUPPORTS THE DELICATE PHOTORECEPTOR CELLS

• B)GATHERS,FOCUSES AND PROCESSES LIGHT INTO PRECISE IMAGES

PARTS

1. ANTERIOR POLE

2. POSTERIOR POLE

3. TUNICS( EXTERNAL WALL)

4. HUMORS( FLUID ) INSIDE

5. LENS

TUNICS

FIBROUS VASCULAR SENSORY

SCLERA

CORNEA

CHORIOD

CILIARY BODY

IRIS

RETINA

• 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)

• 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

INTERNAL ANATOMY

SAGITTAL SECTION INTERNAL ANATOMY

RETINA

• SENSORY(• INNERMOST)• RETINA( MOST IMPORTANT)

• OUTER ---PIGMENTED( PREVENTS LIGHT SCATTERING)

• INNER---NEURAL ( LIGHT SENSITIVE PHOTORECEPTOR CELLS, BIPOLAR AND GANLION CELLS

• PHOTORECTORS----RODS/ CONES

LIGHT

PHOTORECEPTOR

BIPOLAR CELLS

GANGLION CELLS

OPTIC NERVE

BRAIN

OPTIC NERVE

EAR• RECEPTOR ORGAN FOR

HEARING AND EQUILIBRIUM• OUTER/ MIDDLE EAR------

HEARING• INNER

EAR----HEARING/EQUILIBRIUM• OUTER EAR• PINNA---AURICLE( ELASTIC

CARTILGE,EXCEPT—LOBULE)• EXT ACOUSTIC MEATUS—

2.5MM TUBE---AURICLE----EAR DRUM( EAR WAX)

• EAR DRUM---TYMPANIC MEMBRANE---BOUNDARY BETWEEN OUTER AND MIDDLE EAR

SOUND WAVES

EAR DRUM

OSSICLES

INNER EAR

MIDDLE EAR

• ALSO CALLED TYMPANIC CAVITY• AIR FILLED / INSIDE THE PETROUS TEMPORAL• LATERAL BOUNDARY—TYMPANIC MEMBRANE, MEDIAL

BOUNDARY—BONE SEPERATING IT FROM THE MIDDLE EARSUPERIOR BOUNDARY-PETROUS TEMPORALPOSTERIOR WALL—MASTOIOID ANTRUMINFERIOR BOUNDARY----BONE/IJVANTERIOR BOUNDARY-BEHIND ICA• MEDIAL WALL---OVAL AND ROUND WINDOW• PHARYNGOTYMPANIC TUBE CONNECTS IT TO THE

NASOPHARYNX• OSSICLE ARE PRESENT • 2 MUSCLES- STAPEDIUS/ TENSOR TYMPANI

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

SEMICIRCULAR CANALS

VESTIBULE SEMICIRCULAR DUCTS

UTRICLE/SACCULE

EQUILIBRIUM

HEARING

COCHLEA

COCHLEAR DUCT