cranium rtec 233 fall 2008 fall 2008 week 1 & 2. cranial anatomy calvaria calvaria frontal...

Cranium Cranium

RTEC 233RTEC 233

Fall 2008Fall 2008

Week 1 & 2Week 1 & 2

Cranial AnatomyCranial Anatomy

CalvariaCalvaria

FrontalFrontal

OccipitalOccipital

Left ParietalLeft Parietal

Right ParietalRight Parietal

FloorFloor

EthmoidEthmoid

SphenoidSphenoid

Left TemporalLeft Temporal

Right TemporalRight Temporal

The regions of the Cranial The regions of the Cranial FloorFloor

Anterior: extends form anterior frontal Anterior: extends form anterior frontal bone to the lesser wings of the sphenoidbone to the lesser wings of the sphenoid It is associated with frontal lobes of cerebellumIt is associated with frontal lobes of cerebellum

Middle: Extends from lesser wings to the Middle: Extends from lesser wings to the apices of petrous ridges of temporal boneapices of petrous ridges of temporal bone Accommodates temporal lobes and associated Accommodates temporal lobes and associated

neurovascular structuresneurovascular structures

Posterior: deep depression posterior to Posterior: deep depression posterior to petrous ridge petrous ridge which protects cerebellum, pons and medulla which protects cerebellum, pons and medulla

oblongataoblongata

Frontal BoneFrontal Bone

Has a vertical and Has a vertical and horizontal portionhorizontal portion Vertical portion- Vertical portion-

forms the forehead forms the forehead and anterior part of and anterior part of the vaultthe vault

Horizontal portion- Horizontal portion- forms roof of orbits, forms roof of orbits, part of the roof of part of the roof of nasal cavity, and nasal cavity, and greater part of greater part of anterior cranial anterior cranial fossa.fossa.

Parietal BoneParietal Bone Forms large part of Forms large part of

sides of the craniumsides of the cranium

Forms posterior Forms posterior portion of the portion of the cranial floorcranial floor

Parietal eminence is Parietal eminence is used to measure used to measure width of headwidth of head

Occipital BoneOccipital Bone Inferosuperior portion of calvariaInferosuperior portion of calvaria Squamous portion is superior to inionSquamous portion is superior to inion Ext. occipital protuberance – prominent bulge Ext. occipital protuberance – prominent bulge Contains foramen magnum and articulates Contains foramen magnum and articulates

with atlas (C1)with atlas (C1)

Ethmoid BoneEthmoid Bone Horizontal portion is called cribiform plateHorizontal portion is called cribiform plate

Vertical portion is called perpendicular plateVertical portion is called perpendicular plate

2 light spongy labyrinths2 light spongy labyrinths

Sphenoid BoneSphenoid Bone Resembles shape of Resembles shape of

a bata bat

Consists of a body, 2 Consists of a body, 2 lesser wings, 2 lesser wings, 2 greater wings, 2 greater wings, 2 pterygoid processespterygoid processes

Contains Sella Contains Sella turcica- important turcica- important for positioning errorsfor positioning errors

Sella TurcicaSella Turcica

Lies in the MSP Lies in the MSP ¾” anterior & ¾” anterior &

superior to EAMsuperior to EAM

Deformity of the Deformity of the sella is often the sella is often the only clue that a only clue that a lesion exists lesion exists intracraniallyintracranially

Temporal BoneTemporal Bone Divided in 3 partsDivided in 3 parts

Squamous: upper Squamous: upper portion forming part portion forming part of the wall of skullof the wall of skull

Mastoid: Posterior to Mastoid: Posterior to EAM contains EAM contains mastoid tip (process)mastoid tip (process)

Petrous: dense & Petrous: dense & houses organs of houses organs of hearing and balancehearing and balance

Thickest most dense Thickest most dense bone in craniumbone in cranium

Level of TEALevel of TEA

Superior CraniumSuperior Cranium

Visualized more Visualized more clearly:clearly: SphenoidSphenoid TemporalsTemporals OccipitalOccipital FrontalFrontal

Not well visualized:Not well visualized: EthmoidEthmoid ParietalsParietals

Copyright © 2003, Mosby, Inc.

Lateral CraniumLateral Cranium

From this view you can visualize From this view you can visualize all the cranial bonesall the cranial bones


Infant SuturesInfant Sutures& Fontanels& Fontanels AnteriorAnterior

Close approx 2 yearsClose approx 2 years

2 Mastoids2 Mastoids Close approx 2 yearsClose approx 2 years

2 Sphenoidal2 Sphenoidal 1-3 months old1-3 months old

PosteriorPosterior 1-3 months1-3 months


Adult SuturesAdult Suturesand Junctionsand Junctions Sutures:Sutures:

Coronal Coronal

SagittalSagittal

SquamosalSquamosal

LamboidalLamboidal

JunctionsJunctions

BregmaBregma

LambdaLambda

PterionPterion

AsterionAsterionCopyright © 2003, Mosby, Inc.

Lets compareLets compare

InfantInfant Anterior fontanel Anterior fontanel

Posterior fontanel Posterior fontanel

Sphenoidal fontanelsSphenoidal fontanels

Mastoidal fontanels Mastoidal fontanels

AdultAdult BregmaBregma

LambdaLambda

PterionsPterions

AsterionsAsterions

Anterior CraniumAnterior Cranium

Not able to Not able to visualize:visualize: OccipitalOccipital EthmoidEthmoid

Able to visualize:Able to visualize: ParietalsParietals FrontalFrontal SphenoidSphenoid TemporalsTemporals


Cranial TopographyCranial Topography

SurfaceSurfaceLandmarksLandmarks

Skull morphologySkull morphology Mesocephalic: Mesocephalic:

averageaverage 47 degrees47 degrees

Brachycephalic: Brachycephalic: Short and broad Short and broad Width 80% or Width 80% or

greater than lengthgreater than length 54 degrees54 degrees

Dolichocephalic: Dolichocephalic: long and narrowlong and narrow Width is less than Width is less than

75% than the 75% than the lengthlength

40 degrees40 degrees

Skull Positioning LinesSkull Positioning Lines

Skull TopographySkull Topography

GlabellaGlabella Inner canthusInner canthus Outer canthusOuter canthus NasionNasion Infraorbital Infraorbital

marginmargin AcanthionAcanthion

GonionGonion Mental pointMental point External auditory External auditory

meatus (EAM)meatus (EAM) Auricular pointAuricular point Top of ear Top of ear

attachment (TEA)attachment (TEA)

Be able to locate the following landmarks:

Radiographic LandmarksRadiographic Landmarks

Interpupillary line (IPL)Interpupillary line (IPL) Perpendicular line between pupils of Perpendicular line between pupils of

eyeseyes Acanthiomeatal line (AML)Acanthiomeatal line (AML)

From acanthion to EAMFrom acanthion to EAM Mentomeatal line (MML)Mentomeatal line (MML)

From mental point (center of chin) to From mental point (center of chin) to EAMEAM

Radiographic LandmarksRadiographic Landmarks

Orbitomeatal line (OML)Orbitomeatal line (OML) From outer canthus to EAMFrom outer canthus to EAM

InfraorbitomeatalInfraorbitomeatal line (IOML)line (IOML) From infraorbital margin to EAMFrom infraorbital margin to EAM

Glabellomeatal line (GML)Glabellomeatal line (GML) From glabella to EAMFrom glabella to EAM

Positioning AidsPositioning AidsUse any straightedge:•Straw•Pen/pencil

Most Common Positioning Most Common Positioning ErrorsErrors

RotationRotation

TiltTilt

Excessive FlexionExcessive Flexion

Excessive ExtensionExcessive Extension

Incorrect CR angleIncorrect CR angle

Rotation

TiltCopyright © 2005, Mosby, Inc.

Indications for Cranial Indications for Cranial RadiographyRadiography

Skull fracturesSkull fractures

LinearLinear DepressedDepressed Basal skullBasal skull

Gunshot woundsGunshot wounds

Pituitary AdenomasPituitary Adenomas

Subdural hematomaSubdural hematoma

NeoplasmsNeoplasms MetastasesMetastases

OsteolyticOsteolytic OsteoblasticOsteoblastic Combo of bothCombo of both

Multiple myelomaMultiple myeloma

Paget’s DiseasePaget’s Disease

Acoustic neuromaAcoustic neuroma

http://www.skullbaseinstitute.com/vidhttp://www.skullbaseinstitute.com/video_pituitary_tumor.htmeo_pituitary_tumor.htm

http://www.skullbaseinstitute.com/http://www.skullbaseinstitute.com/video_acoustic_neuroma.htmvideo_acoustic_neuroma.htm

http://www.skullbaseinstitute.com/video_pituitary_tumor.htm

http://www.skullbaseinstitute.com/video_pituitary_tumor.htm

Disinfect the Table or Disinfect the Table or Bucky!!Bucky!!

CleanlinessCleanliness

Hair and skin of face are naturally Hair and skin of face are naturally oily; illness often increases oilinessoily; illness often increases oiliness

Cranial procedures require direct Cranial procedures require direct contact of patient’s face with VBScontact of patient’s face with VBS

CleanClean device after each patient device after each patient WashWash your hands!!! your hands!!!

Radiation ProtectionRadiation Protection

Collimate to anatomy of interestCollimate to anatomy of interest Shield gonads/abdomen of pediatric Shield gonads/abdomen of pediatric

patients and those of reproductive agepatients and those of reproductive age Shield thyroid and thymus of pediatric Shield thyroid and thymus of pediatric

patient when doing so will not interfere patient when doing so will not interfere with demonstration of anatomy of with demonstration of anatomy of interestinterest

Good communication and positioning Good communication and positioning skills reduce chance of need for repeat skills reduce chance of need for repeat radiographsradiographs

General Body PositionGeneral Body Position

Hyposthenic/asthenic patients Hyposthenic/asthenic patients usually need support at chest to usually need support at chest to elevate C-spineelevate C-spine Helps prevent downward tilt of MSPHelps prevent downward tilt of MSP

Hypersthenic patients require Hypersthenic patients require radiolucent support at headradiolucent support at head Helps prevent upward tilt of MSPHelps prevent upward tilt of MSP

Hyposthenic/Asthenic Hyposthenic/Asthenic PatientsPatients

Hypersthenic PatientsHypersthenic Patients

Positioning: Lateral SkullPositioning: Lateral Skull

Seated upright or Seated upright or semi-pronesemi-prone

MSP is parallel to IRMSP is parallel to IR

Interpupillary line is Interpupillary line is perpendicular to IRperpendicular to IR

Suspend respirationSuspend respiration

CR enters 2” superior CR enters 2” superior to EAMto EAM


Positioning Trauma Lateral Positioning Trauma Lateral SkullSkull

Supine with sponge Supine with sponge under headunder head

MSP is parallel to IRMSP is parallel to IR

Interpupillary line is Interpupillary line is perpendicular to IRperpendicular to IR


CR enters 2” superior CR enters 2” superior to EAMto EAM


Lateral SkullLateral Skull

Lateral Skull RadiographLateral Skull Radiograph Entire cranium without Entire cranium without

rotation/tiltrotation/tilt

SI orbital roofs, SI orbital roofs, greater wings of greater wings of sphenoid, and TMJ’ssphenoid, and TMJ’s

Sella turcica in profileSella turcica in profile

Penetration of parietal Penetration of parietal

No overlap c-spine by No overlap c-spine by mandiblemandible


Common PA projectionsCommon PA projections

PA projections Skull

0 degrees

Frontal bone

15 degree caudal

Caldwell

25 – 30 caudal

Rotundum foramina, Superior orbital

fissures

Positioning PA, PA Axial & Positioning PA, PA Axial & CaldwellCaldwell

Prone or seated uprightProne or seated upright

Forehead and nose Forehead and nose against bucky or tableagainst bucky or table

OML perpendicular to IROML perpendicular to IR

MSP perpendicular to IRMSP perpendicular to IR

Respiration: suspendRespiration: suspend

CR: 0, 15 caudal or 25-CR: 0, 15 caudal or 25-30 caudal, exiting 30 caudal, exiting nasionnasion Copyright © 2003, Mosby, Inc.

Trauma PA and PA Axial Trauma PA and PA Axial SkullSkull

Semi supine: 1 side Semi supine: 1 side elevated to place head elevated to place head in true lateralin true lateral

Sponge under head Sponge under head

Nose and forehead Nose and forehead against vertical IRagainst vertical IR

OML perpendicular to OML perpendicular to IRIR

Direct horizontal CR Direct horizontal CR perpendicular or 15 perpendicular or 15 degrees caudad to degrees caudad to exit nasionexit nasion


PA and Caldwell PA and Caldwell RadiographsRadiographs

Entire skull with no Entire skull with no rotation or tiltrotation or tilt

Petrous ridges in lower 1/3 Petrous ridges in lower 1/3 of orbits with 15 caudalof orbits with 15 caudal

Petrous ridges fill orbits Petrous ridges fill orbits with horizontal beamwith horizontal beam

Density and contrast are Density and contrast are sufficientsufficient

No motionNo motion

Nasion in center of film, Nasion in center of film, close collimationclose collimation


Similarities and DifferencesSimilarities and Differences

Exit nasionExit nasion

Require close Require close collimationcollimation

OML is perpendicular to OML is perpendicular to plane of IRplane of IR

All axials have caudal All axials have caudal anglesangles

Respiration suspendedRespiration suspended

Position of petrous Position of petrous ridgesridges

Best seen Best seen

Body positionBody position

Where the CR entersWhere the CR enters

Positioning: AP & AP Axial Positioning: AP & AP Axial SkullSkull

SupineSupine

OML perpendicular to OML perpendicular to IRIR

CR directed at nasion CR directed at nasion with a horizontal beam with a horizontal beam or 15 degrees cephalicor 15 degrees cephalic


AP Skull RadiographAP Skull Radiograph Entire skull with no Entire skull with no

rotation or tiltrotation or tilt

Petrous ridges in lower 1/3 Petrous ridges in lower 1/3 of orbits with 15 cephaladof orbits with 15 cephalad

Petrous ridges fill orbits Petrous ridges fill orbits with horizontal beamwith horizontal beam

Density and contrast are Density and contrast are sufficientsufficient

No motionNo motion

Nasion in center of film, Nasion in center of film, close collimationclose collimation

Image is magnified Image is magnified compared to PAcompared to PA


Positioning AP Axial (Towne)Positioning AP Axial (Towne)

Supine or seated uprightSupine or seated upright

MSP perpendicular to plane MSP perpendicular to plane of IRof IR

OML or IOML perpendicular OML or IOML perpendicular to IRto IR


CR 30 degrees caudal CR 30 degrees caudal (OML) or 37 caudal (IOML).(OML) or 37 caudal (IOML).

CR enters 2 ½” above CR enters 2 ½” above glabella through the level glabella through the level of EAMof EAM


AP Axial (Towne) AP Axial (Towne) RadiographRadiograph

Equal distance from Equal distance from lateral border of skull lateral border of skull to foramen magnumto foramen magnum

Symmetric petrous Symmetric petrous ridgesridges

Dorsum sellae and Dorsum sellae and posterior clinoid posterior clinoid processes visible processes visible through foramen through foramen magnummagnum

Penetration of occipital Penetration of occipital bone without excessive bone without excessive densitydensity

Sella TurcicaSella Turcica

Townes ComparisonTownes Comparison

Positioning PA Axial (Haas)Positioning PA Axial (Haas)

Prone or seated uprightProne or seated upright

Forehead and nose on table Forehead and nose on table or grid deviceor grid device

MSP perpendicular to the MSP perpendicular to the gridgrid

OML perpendicular to IROML perpendicular to IR


CR 25 degrees cephalad CR 25 degrees cephalad entering 1 1/2 “ below entering 1 1/2 “ below occipital protuberance.occipital protuberance.

R exits 1 ½” superior to R exits 1 ½” superior to nasionnasion

PA Axial (Haas) RadiographPA Axial (Haas) Radiograph Prone or seated Prone or seated

uprightupright

MSP & OML MSP & OML perpendicularperpendicular


Directed cephalic 25 Directed cephalic 25 degrees to enter 1 ½” degrees to enter 1 ½” below the inion.below the inion.

Exit 1 ½” superior to Exit 1 ½” superior to nasion. nasion.


Haas Haas PA AxialPA Axial

Positioning SMV (Schüller)Positioning SMV (Schüller) Supine or seated Supine or seated

uprightupright

IOML parallel to IRIOML parallel to IR

MSP perpendicular to MSP perpendicular to IRIR


CR enters the MSP of CR enters the MSP of the throat between the throat between angles of mandible and angles of mandible and passes through a point passes through a point ¾”anterior to EAMS.¾”anterior to EAMS.

SMV (Schüller) RadiographSMV (Schüller) Radiograph Adequate penetration Adequate penetration

of cranial baseof cranial base

Equal distance from Equal distance from lateral border of skull lateral border of skull to condylesto condyles

SI of mental SI of mental protuberance over protuberance over anterior frontal boneanterior frontal bone

Condlyes anterior to Condlyes anterior to petrous ridgespetrous ridges

Symmetric petrosaeSymmetric petrosae

Positioning VSM (Schüller)Positioning VSM (Schüller)

ProneProne

Chin resting on tableChin resting on table

MSP perpendicular to MSP perpendicular to IRIR


CR directed CR directed perpendicular to IOML.perpendicular to IOML.

CR passes through ¾” CR passes through ¾” anterior to level of anterior to level of EAMSEAMS

VSM (Schüller) RadiographVSM (Schüller) Radiograph

Adequate penetration Adequate penetration of cranial baseof cranial base

Equal distance from Equal distance from lateral border of skull lateral border of skull to condylesto condyles

SI of mental SI of mental protuberance over protuberance over anterior frontal boneanterior frontal bone

Condlyes anterior to Condlyes anterior to petrous ridgespetrous ridges

Symmetric petrosaeSymmetric petrosae

SMV SMV

What is wrong with this What is wrong with this Caldwell?Caldwell?

What is wrong with this What is wrong with this lateral skull?lateral skull?

What is wrong with this What is wrong with this Towne’s?Towne’s?

cranium rtec 233 fall 2008 fall 2008 week 1 & 2. cranial anatomy calvaria calvaria frontal...

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lesser wings

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