ANTERIOR CRANIAL FOSSA (ROOF OF NASAL CAVITY, ORBIT)

MIDDLE CRANIAL FOSSA (ORBIT, NASAL CAVITY, FACE)

POSTERIOR CRANIAL FOSSA (FACE, ORAL CAVITY, NECK)

V. CRANIAL CAVITY- DIVIDED INTO DEPRESSIONS (FOSSAE)

ANTERIOR CRAN. FOSSA -BONES: FRONTAL, ETHMOID, SPHENOID;

LOOK FOR: suture on floor of fossa: between frontal and Lesser wing of sphenoid

MIDDLE CRAN. FOSSA - BONES: SPHENOID, TEMPORAL, PARIETAL

LOOK FOR: sharp edge of Petrous part of Temporal bone: attachment of Tentorium Cerebelli

POSTERIOR CRAN FOSSA -BONES: SPHENOID, TEMPORAL, OCCIPITAL, PARIETAL

LOOK FOR: Foramen Magnum: on cadavers level indicated by Vertebral Artery

LESSER WINGOF SPHENOID

GREATER WINGOF SPHENOID

PETROUS PART OF TEMPORAL BONE

PETROUS PART OF TEMPORAL BONE

TENTORIUMCEREBELLI

SKULL SESSION 1: FORAMINA OF INTERIOR OF SKULL AND CRANIAL NERVES

Basic facts:

1) Cranial nerves are numbered 1-12

2) Learn foramina of interior of skull in anterior-posterior sequence; this reflects numbering of cranial nerves

I. Olfactory II. OpticIII. OculomotorIV. TrochlearV. TrigeminalVI. AbducensVII. FacialVIII. Vestibulo-cochlear IX. GlossopharyngealX. VagusXI. Accessory XII. Hypoglossal

CRANIAL NERVES

A. Contain inflow/outflow of brain; spinal nerves contain inflow/outflow of spinal cord.B. Contain types of similar to those found in spinal nerves; ex. sensory axons to skin.C. Contain types of neurons not found in spinal nerves; ex. taste fibers.D. Many cranial nerves contain more than one type of neuron.E. To analyze types of neurons in different cranial nerves, system of classification of types of neurons.

CRANIAL NERVES

CRANIALNERVES

SPINALNERVES

Seven types of neurons - some are the same types of neurons as are found in spinal nerves; others are only found in cranial nerves

A. Same types as spinal nerves

1. Somatic motor - Voluntary skeletal muscles (derived from somites)

2. Somatic sensory - Precise sensation to skin joints, muscle, tendon receptors (in head, also nasal and oral cavities)

3. Visceral motor (efferents) = AUTONOMICS - smooth muscles (including arrector pilae muscles of skin), blood vessels; secretomotor to glands.

4. Visceral sensory - Imprecise sensation from gut, blood vessels, glands, internal organs (in head, pharynx which is rostral end of gut)

2) CLASSIFICATION OF INNERVATION

WHERE/WHAT IS THE PHARYNX?

NASALCAVITY

ORALCAVITY

PHARYNX -region behindOral and Nasal Cavities

PHARYNX IS CONNECTED TO TRACHEA (RESPIRATORY SYSTEM) AND ESOPHAGUS (GI) SYSTEMtrachea

esophagus

VII

IX

IX

2) CLASSIFICATION OF INNERVATION

B. Only in cranial nerves

5. Special senses - vision, hearing (auditory), balance (vestibular apparatus)

6. Chemical senses - taste and smell

7. Branchiomotor - Voluntary skeletal muscles from branchial arches

MOST CRANIAL NERVES ARE RELATIVELY SIMPLE

CONTAIN ONLY ONE TYPE OF NEURONSENSORYI - Olfactory nerve - Chemical sense - smellII - Optic nerve - Special sense- visionVIII - Vestibulo-cochlear nerve - Special senses -hearing, balance

MOTORXII - Hypoglossal - muscles of tongue - Somatic motorXI - Accessory - motor to Sternocleidomastoid, Trapezius - BranchiomotorIV - Trochlear - eye muscle - Superior Oblique -Somatic motorVI - Abducens - eye muscle - Lateral Rectus - Somatic motor

MOST CRANIAL NERVES ARE RELATIVELY SIMPLE

CONTAIN ONLY TWO TYPES OF NEURONS

MOTOR AND AUTONOMICIII - Oculomotor - Somatic motor - many eye muscles and Lev. Palp. Sup.+ Visceral motor - Parasympathetics (Constrictor pupil, Ciliary muscle)

MOTOR AND SENSORYV - Trigeminal - Branchiomotor - Incantation Arch I(Muscles of mastication, Tensor tympani, Tensor palati, Mylohyoid, Anterior belly of Digastric)+ Somatic Sensory - Skin, joints, properioception: Oral cavity, Nasal cavity.

VII, IX and X are complex and have a number of types of neurons

CRANIAL NERVE CHART: TYPES OF NEURONS

X

Branchio-motor

VisceralMotor(Parasymp.)

SomaticSensory

VisceralSensory

Taste,Smell

IX, X: Remember- Facial - Muscles facial expression + incantation- name: Glossopharyngeal - Glosso - post. 1/3 tonguetaste, touch; Pharyngeal - oropharynx sensory; also visceral sensory = CAROTID SINUS (blood pressure), CAROTID BODY (blood chemo)- Vagus - incantation - Larynx (sensory/motor), Pharynx motor (except Stylopharygeus, Soft palate (except Tensor Palati)

PARASYMPATHETICS - IN CRANIAL NERVES

+palate

III

VII

IXX

PRE-GANGLIONICNEURONSLEAVEWITHCRANIALNERVES

GANGLIA CLOSE TO TARGET ORGAN

(Constrictor) =

CHEMICAL SENSES - TASTE - in three cranial nerves

X - VAGUS -ant. to epiglottis

IX - GLOSSO-PHARYNGEALpost. 1/3 of tongue

VII - FACIAL -ant. 2/3 of tongue

TONGUE

FIRSTARCH

SECONDARCH

THIRDARCH

FOURTHARCH

CAUDAL SIXTHARCH

note: Innervation pattern of Cranial Nerves applies to muscles of branch ARCHES: DOES NOT APPLY TO POUCHES OR CLEFTS

IICRANIAL NERVESARE NUMBEREDACCORDINGTO THEIR POSITION ON THE BRAINSTEM

IIIIVVVI

VII, VIIIIX, XXI

XII

ANTERIOR

POSTERIOR

CRANIAL NERVES

I

II

III, IV, V1, VIV2V3Middle Meningeal A.VII, VIIIIX, X, XIXII

NOSE

OLFACTORYFORAMEN –CN IOLFACTORYNERVE

CRISTAGALLIOFETHMOID

CHEMICAL SENSES - TASTE AND SMELL

I - OLFACTORY NERVE -SMELL

TEST: SMELL ODORS(note: not ammonia; painin nasal cavity CN5)

DAMAGE:LOSS OF SENSE OFSMELL (ANOSMIA)

also: can be damagedby fractures (blows) tonose

OPTICFORAMEN CN IIOPTICNERVE,OPHTHALMICARTERY

SPECIAL SENSES

Detect light - Test visual acuity

II -OPTICNERVE

fiberscross atopticchiasm

Retina

DAMAGE OPTIC NERVE: loss ofvision in one eye

DAMAGE VISUAL PATHWAY:more complex visual fielddeficits

Note: Branches of Ophthalmic Artery supply eye: Posterior Ciliary Arteries and Central Artery of Retina enter posterior side of Eyeball

BLOOD SUPPLY TO ORBIT: OPHTHALMIC ARTERYOPHTHALMICARTERY

OPHTHALMICARTERY

SUPRAORBITALARTERY

SUPRATROCHLEARARTERY

MAJOR BRANCHESTO EYE:

2) CENTRALARTERY OFRETINA1) POSTERIOR CILIARY ARTERIES (Long and Short)

(ANT. CILIARY ARTERIES - small, derived from branches to muscles) OPTIC

NERVE

INTERNALCAROTIDARTERY

CONTAINS RODS AND CONES (PHOTOSENSITIVE)CENTRAL ARTERY OF RETINA- BRANCH OF OPHTHALMIC ART.NO ANASTOMOSES; OCCLUSIONRESULTS IN BLINDNESS

CENTRAL ARTERY OF RETINA

RETINA

EYE- STRUCTURE OF EYEBALL- RETINA

OPHTHALMOSCOPE VIEW

BRANCHES OFCENTRAL ARTERYAND VEIN OFRETINA

OPTIC NERVE(DISC)

MACULA =visual acuity

DURA AND SUBARACHNOID SPACE (CSF) EXTEND AROUND OPTIC NERVE; INCREASE IN CSF (PRESSURE) CANAFFECT VISION

SUBARACHNOID SPACE EXTENDS TO BACK OF EYEBALL

CSF INSUBARACHNOIDSPACE

PAPILLEDEMA - engorgementof retinal veins (correspond to branches of central artery)

Clinical - slow onset;headaches

DURA

PAPILLEDEMA = swelling of optic disc

SUPERIORORBITALFISSURE –CN III, IVV1, VIOPHTHALMICVEINS

Boundary-Lateral edgeof eye

Boundary Lateral edgeof mouth

IV. SENSORY INNERVATION - TRIGEMINAL NERVE -TO SKIN OF HEAD – 3 DIVISIONS

V1 – OPHTHALMICDIVISION -SOMATIC SENSORY

V2 – MAXILLARYDIVISON -SOMATIC SENSORY

V3 – MANDIBULARDIVISION - SOMATIC SENSORY + BRANCHIOMOTOR

V1

V2

V3

CAVERNOUSSINUS

SELLA TURCICA

VENOUS SINUSES

7. Cavernous sinuses - in middle cranial fossa; on side of the body of the sphenoid bone; connected by Intercavernous sinus; receive blood from Sup. and Inf. Ophthalmic veins, Cerebral veins; drain to Sup. and Inf. Petrosal sinuses

8. Sup. and Inf. Petrosal sinuses - on petrous part of temporal boneSup. drains to TransverseInf. Drains to Internal Jugular

PITUITARY

CAV.SINUS

INTERNALCAROTID

IIIIV

V1,V2

VI

STRUCTURES PASSING THROUGH WALL OF CAVERNOUSSINUS - Int. Carotid A., Cranial N.'s III, IV, V1, V2, VI;Clinical sign of Infection in Sinus – ‘BLURRED’ VISION

III IV

VI

FORAMENROTUNDUM –CN V2

Boundary-Lateral edgeof eye

Boundary Lateral edgeof mouth

IV. SENSORY INNERVATION - TRIGEMINAL NERVE -TO SKIN OF HEAD – 3 DIVISIONS

V1 – OPHTHALMICDIVISION -SOMATIC SENSORY

V2 – MAXILLARYDIVISON -SOMATIC SENSORY

V3 – MANDIBULARDIVISION - SOMATIC SENSORY + BRANCHIOMOTOR

V1

V2

V3

FORAMENOVALE –CN V3

FORAMENSPINOSUM

F. BLOOD SUPPLY TO CALVARIUM

1) OUTER SURFACE –ARTERIES TO SCALP

2) INNER SURFACE-MENINGEAL ARTERIES

COURSE NEXT TO BONE; MISNAMED - SOUND LIKE SUPPLY MENINGES- MOST BLOOD TO BONES

Clinical - bleeding is arterial; can be profuse and rapid (ex, car accident); patient lucid at first; can be fatal within hours if herniation occurs

Skull Fracture Near Pterion

EPIDURAL HEMATOMA

TearMiddleMeningealArtery

1) Skull fracture near Pterion2) Tear Middle Meningeal Artery3) Blood 'peels' durafrom bone4) Lens shaped (biconvex)mass on CT

5) mass candisplace brain

6) Herniation -i. Uncal herniation -push Temporal lobe (uncus) through Tentorial Notchii. Tonsillar herniation -push Cerebellum (tonsil) through Foramen Magnum

Uncalherniation

Tonsillar herniation

OPENINGOFCAROTIDCANAL(FORAMENLACERUM)

CAROTIDCANAL –OPENS TOFORAMENLACERUMINSIDEMIDDLECRANIALFOSSA

OPENINGOFCAROTIDCANAL(FORAMENLACERUM)

INTERNAL CAROTID ARTERY: ENTERS SKULL

PASSESTHROUGHCAVERNOUSSINUS

INTERNALCAROTIDARTERY

PITUITARY

CAV.SINUS

INTERNALCAROTID

IIIIV

V1,V2

VI

STRUCTURES PASSING THROUGH WALL OF CAVERNOUSSINUS - Int. Carotid A., Cranial N.'s III, IV, V1, V2, VI;Clinical sign of Infection in Sinus – ‘BLURRED’ VISION

INTERNALCAROTID

INTERNALAUDITORYMEATUS –VII, VIII

VII BRANCHIOMOTOR MUSCLES OF FACIAL EXPRESSION

FACIALPARALYSIS

STYLOHYOID,POST. BELLY DIGASTRIC

STAPEDIUS - dampens sound -DAMAGE HYPERCOUSIA - sounds seem too loud

sagging faceloss of naso-labial foldinability to close eye

view insideMiddle ear

view of Neck

Mandible = jaw bone

Stapes - bone of middle ear

CHEMICAL SENSES - TASTE - in three cranial nerves

X - VAGUS -ant. to epiglottis

IX - GLOSSO-PHARYNGEALpost. 1/3 of tongue

VII - FACIAL -ant. 2/3 of tongue

TONGUE

SPECIAL SENSES

VIII -VESTIBULO-COCHLEAR

to 1) cochlea - hearing2) semicircular canals -(vestibular apparatus) -balance

in petrous part oftemporal bone

VIII

DAMAGE - LOSS OF HEARINGON ON SIDE

JUGULARFORAMEN –CN IX, X, XI

CN X -most muscles of soft palate

CN X -mot muscles of pharynx

CN X -muscles of larynx

CN IX -stylo-pharyngeus

BRANCHIOMOTOR - IX GLOSSOPHARYNGEALAND X VAGUS

soft palate TEST BY HAVING PATIENTSAY AAHH! (also GAG REFLEX)

STERNOCLEIDO-MASTOID

TRAPEZIUS

XI - ACCESSORY NERVE

Branchiomotor to twomuscles

CLINICAL: TORTICOLLIS –Contracture of Sternocleidomastoid;Face turned to opposite side

Shrugshoulders

Turn head

HYPOGLOSSALCANAL –CN XII

FORAMENMAGNUM

PROTRUDED TONGUE DEVIATES TOWARD SIDE OF LESION - due to unopposed action of the Genioglossus muscle which protrudes tongue.

HYPOGLOSSAL NERVE (XII) - ALL MUSCLES OF TONGUE - SOMATIC MOTOR

DAMAGEHYPOGLOSSALNERVE ON ONESIDE

GENIO-GLOSSUSINTACT

GENIO-GLOSSUSPARALYZED

VENOUS SINUSES OF BRAINSUPERIOR SAGITTAL SINUS

INFERIORSAGITTALSINUS

STRAIGHTSINUS

TRANSVERSESINUS

CAVERNOUSSINUS

SIGMOID SINUS

INTERNAL JUGULARVEIN

falx cerebri

tentorium cerebelli

TransverseTransverse

Sigmoid

VENOUS SINUSES4. Transverse sinuses - in lateral fixed part of tentorium; receive blood from Sup. Sagittal or Confluens5. Sigmoid sinuses - S-shaped continuation of Transverse; endin Jugular Foramen; form Internal Jugular Vein6. Occipital Sinuses - in falx cerebelli; drain to Confluens

Sigmoid

NOSE

VENOUS SINUSES MAKE GROOVES IN CRANIAL CAVITY

TRANSVERSESINUS

SIGMOIDSINUS

VENOUS SINUSES

7. Cavernous sinuses - in middle cranial fossa; on side of the body of the sphenoid bone; connected by Intercavernous sinus; receive blood from Sup. and Inf. Ophthalmic veins, Cerebral veins; drain to Sup. and Inf. Petrosal sinuses

8. Sup. and Inf. Petrosal sinuses - on petrous part of temporal boneSup. drains to TransverseInf. Drains to Internal Jugular

VENOUS SINUSES MAKE GROOVES IN CRANIAL CAVITY

INFERIORPETROSALSINUS

SUPERIORPETROSALSINUS

CAVERNOUSSINUS

RIGIDLY LINKED FOR EYE MOVEMENTS

A. BOUNDARIES

1. ROOFFRONTAL

4. LATERAL WALLZYGOMATIC SPHENOID

2. FLOORMAXILLARY

SPHENOID

ZYGOMATIC

I. BONES OF ORBIT

MAXILLARY

3. MEDIAL WALL - INCLUDES MAXILLARY, LACRIMAL, ETHMOID, FRONTAL AND SPHENOID BONES (NASAL CAVITY IS MEDIAL TO MEDIAL WALL OF ORBIT)

MAXILLARY

LACRIMAL

ETHMOIDSPHENOID

BONES OF ORBIT

FRONTAL

NOSE

FORAMINA- MOST THINGS ENTER ORBIT FROM MIDDLE CRANIAL FOSSA

1) OPTIC CANAL- IN BASE OF LESSER WING OF SPHENOID BONE, CONTAINS OPTIC NERVE (II) and OPHTHALMIC ARTERY

2) SUPERIOR ORBITAL FISSURE - BETWEEN GREATER AND LESSER WINGS OF SPHENOID, CONTAINS III, IV, V1, VI, OPHTHALMIC VEINS

B. FORAMINA OF ORBIT

OPTICFORAMEN CN IIOPTICNERVEOPHTHALMICARTERY

SUPERIORORBITALFISSURE –CN III, IVV1, VI,OPHTHALMICVEINS

1) OPTIC CANAL- IN BASE OF LESSER WING OF SPHENOID BONE,CONTAINS OPTIC NERVE AND OPHTHALMIC ARTERY

2) SUPERIOR ORBITAL FISSUREBETWEEN GREATER AND LESSER WINGS OF SPHENOID, CONTAINS III, IV, V1, VI, OPTHALMIC VEINS

NOSE

INFERIOR ORBITAL FISSURE

1) INFERIOR ORBITAL FISSURE- SLIT BELOW SUP. ORBITAL FISSURE: BETWEEN SPHENOID AND MAXILLARY - CONNECT PTERYGOPALATINE FOSSA AND INFRATEMPORAL FOSSA WITH ORBIT - CONTAINS INFRAORBITAL AND ZYGOMATIC N., A. AND V. (V2, MAXILLARY A.)

3. MEDIAL WALL- INCLUDES MAXILLARY, LACRIMAL, ETHMOID, FRONTAL AND SPHENOID (NASAL CAVITY IS MEDIAL TO MEDIAL WALL OF ORBIT)

MAXILLARY

LACRIMAL

ETHMOIDSPHENOID

BONES OF ORBIT

FRONTAL

NOSE

2) ANT. AND POST. ETHMOIDAL FORAMINA-BETWEEN ETHMOID AND FRONTAL BONES -CONNECT ORBIT AND NASAL CAVITIES -CONTAIN ANT AND POST ETHMOIDAL N., A. AND V. (V1 AND OPHTHALMIC A.)

ANTERIOR AND POSTERIOR ETHMOIDAL FORAMINA

OPENING OF 3) NASOLACRIMAL DUCT- IN MAXILLARY, LACRIMAL BONES AND INF. NASAL CONCHA -CONTAINS MEMBRANEOUS NASOLACRIMAL DUCT AND TEARS

NASOLACRIMAL DUCT

NASOLACRIMAL DUCT

ORBIT- SERVES AS PASSAGEWAY FOR NERVES, VESSELS TO FACE, SCALP AND NASAL CAVITY

1) SUPRAORBITAL NOTCH OR FORAMEN-IN FRONTAL BONE CONTAINS SUPRAORBITAL N., A. and V. FROM V1, OPTHALMIC A. and V.

2) INFRAORBITAL FORAMEN- IN MAXILLARY BONE CONTAINS INFRAORBITAL N., A. and V. FROM V2 AND MAXILLARY

OTHER FORAMINA OF ORBIT