skull & cranial bones extra handout by dr. mohsen dashti imaging procedures 362 march 15 &...

Skull & cranial bones extra Skull & cranial bones extra handouthandout

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Dr. Mohsen DashtiDr. Mohsen DashtiImaging Procedures 362Imaging Procedures 362

March 15 & 18, 2009March 15 & 18, 2009

Mosby items and derived items © 2007, 2003, 1999 by Mosby, Inc., an affiliate of Elsevier Inc.


Anatomy ReviewAnatomy Review

SkullSkull

Slide 2


Skull AnatomySkull Anatomy

Comprised of 22 separate bones divided into Comprised of 22 separate bones divided into two groups:two groups: Cranial bones – 8Cranial bones – 8 Facial bones – 14Facial bones – 14

Cranial bones further subdivided into Cranial bones further subdivided into Calvaria Calvaria FloorFloor



Diploë = inner layer of spongy bone Diploë = inner layer of spongy bone separating two outer plates of compact tissue separating two outer plates of compact tissue Composition of calvarium bonesComposition of calvarium bones


Anterior view of skull


Lateral view of skull


Cranial BonesCranial Bones

CalvariaCalvaria FrontalFrontal OccipitalOccipital R. parietalR. parietal L. parietalL. parietal

FloorFloor EthmoidEthmoid SphenoidSphenoid R. temporalR. temporal L. temporalL. temporal


Superior view of cranial floor



Sutures = fibrous joints that connect the Sutures = fibrous joints that connect the bones of the skullbones of the skull Coronal = between frontal and parietal bonesCoronal = between frontal and parietal bones Sagittal = on top of head between two parietal Sagittal = on top of head between two parietal

bonesbones Squamosal = between temporal bone and the Squamosal = between temporal bone and the

parietal bonesparietal bones Lambdoidal = between occipital and the parietal Lambdoidal = between occipital and the parietal

bonesbones



Bregma = junction of coronal and sagittal Bregma = junction of coronal and sagittal sutures sutures

Lambda = junction of sagittal and lambdoidal Lambda = junction of sagittal and lambdoidal suture suture

Fontanels = areas of incomplete ossification Fontanels = areas of incomplete ossification in Infant skulls, i.e., “soft spots” in Infant skulls, i.e., “soft spots”

Adult cranial size usually achieved by age 12Adult cranial size usually achieved by age 12


Cranial FloorCranial Floor

Internally, divided into three regionsInternally, divided into three regions Anterior cranial fossa – houses frontal lobes of Anterior cranial fossa – houses frontal lobes of

cerebrum; extends from anterior frontal bone to cerebrum; extends from anterior frontal bone to lesser wings of sphenoidlesser wings of sphenoid

Middle cranial fossa – houses temporal lobes; Middle cranial fossa – houses temporal lobes; extends from lesser wings of sphenoid to apices of extends from lesser wings of sphenoid to apices of petrous ridgespetrous ridges

Posterior cranial fossa – deep depression Posterior cranial fossa – deep depression posterior to petrous ridges; protects cerebellum, posterior to petrous ridges; protects cerebellum, pons, and medulla oblongatapons, and medulla oblongata


Skull MorphologySkull Morphology

Typical skull = mesocephalicTypical skull = mesocephalic Petrous pyramids project anteriorly and medially at Petrous pyramids project anteriorly and medially at

angle of 47 degrees from MSPangle of 47 degrees from MSP Brachycephalic skullBrachycephalic skull

Petrous pyramids project anteriorly and medially at Petrous pyramids project anteriorly and medially at angle of 54 degrees from MSPangle of 54 degrees from MSP

Short from front to back, broad from side to side, Short from front to back, broad from side to side, and shallow from vertex to baseand shallow from vertex to base



Dolichocephalic skullDolichocephalic skull Petrous pyramids project anteriorly and medially at Petrous pyramids project anteriorly and medially at

angle of 40 degrees from MSPangle of 40 degrees from MSP Long from front to back, narrow from side to side, Long from front to back, narrow from side to side,

and deep from vertex to baseand deep from vertex to base Asymmetry of outer features should be noted Asymmetry of outer features should be noted

while positioning; for example, the nose may while positioning; for example, the nose may not always be in the midlinenot always be in the midline


Frontal BoneFrontal Bone

Has vertical portion (frontal squama) and Has vertical portion (frontal squama) and horizontal portionshorizontal portions

Frontal squama forms forehead and anterior Frontal squama forms forehead and anterior part of cranial vaultpart of cranial vault

Horizontal portions form orbital plates, part of Horizontal portions form orbital plates, part of roof of nasal cavity, and greater part of roof of nasal cavity, and greater part of anterior cranial fossaanterior cranial fossa



Landmarks to noteLandmarks to note Frontal eminencesFrontal eminences Supraorbital marginsSupraorbital margins Supraciliary archesSupraciliary arches Supraorbital foraminaSupraorbital foramina Glabella Glabella



Frontal sinuses contained between the two Frontal sinuses contained between the two tables of squama on each side of MSPtables of squama on each side of MSP

Articulates with R and L parietals, sphenoid, Articulates with R and L parietals, sphenoid, and ethmoid, nasal bones, and zygomaand ethmoid, nasal bones, and zygoma



Anterior view


Ethmoid BoneEthmoid Bone

Consists of Consists of Horizontal plateHorizontal plate Vertical plateVertical plate Two light, spongy masses = labyrinthsTwo light, spongy masses = labyrinths



Located between the orbits and forms part of Located between the orbits and forms part of anterior cranial fossa, nasal cavity, orbital anterior cranial fossa, nasal cavity, orbital walls, and bony nasal septumwalls, and bony nasal septum

Horizontal portion is called cribriform plateHorizontal portion is called cribriform plate



Cribriform plate contains numerous foramina Cribriform plate contains numerous foramina for transmission of olfactory nervesfor transmission of olfactory nerves

Crista galli = conical projection at anterior Crista galli = conical projection at anterior midline of cribriform platemidline of cribriform plate

Perpendicular plate = vertical portion; forms Perpendicular plate = vertical portion; forms superior portion of bony nasal septumsuperior portion of bony nasal septum



Labyrinths Labyrinths Contain ethmoid sinuses or air cellsContain ethmoid sinuses or air cells Walls form part of medial walls of orbits and lateral Walls form part of medial walls of orbits and lateral

walls of nasal cavitywalls of nasal cavity Have two thin, scroll-shaped projections = superior Have two thin, scroll-shaped projections = superior

and middle nasal conchaeand middle nasal conchae Articulates with frontal, sphenoid, lacrimal, Articulates with frontal, sphenoid, lacrimal,

maxilla, and vomermaxilla, and vomer



Anterior view Lateral view


Parietal BonesParietal Bones

Somewhat square-shapedSomewhat square-shaped Have a convex external surface and concave Have a convex external surface and concave

internal surfaceinternal surface Parietal eminence = prominent bulge near Parietal eminence = prominent bulge near

center of external surface of each bonecenter of external surface of each bone This is the point where the width of the skull This is the point where the width of the skull

should be measured to set techniqueshould be measured to set technique



Articulate with each other at the sagittal Articulate with each other at the sagittal suture in MSP, the frontal, temporal, occipital, suture in MSP, the frontal, temporal, occipital, and sphenoid bones and sphenoid bones



Interior view


Sphenoid BoneSphenoid Bone

Irregular, wedge-shaped bone that resembles Irregular, wedge-shaped bone that resembles a bat (somewhat)a bat (somewhat)

Located in base of cranium anterior to Located in base of cranium anterior to temporal bones and basilar portion of temporal bones and basilar portion of occipitaloccipital



Consists of Consists of BodyBody Two lesser wingsTwo lesser wings Two greater wingsTwo greater wings Two pterygoid processesTwo pterygoid processes



Body contains two sphenoid sinuses and Body contains two sphenoid sinuses and forms posterior bony wall of nasal cavityforms posterior bony wall of nasal cavity

Sella turcica = deep depression on superior Sella turcica = deep depression on superior surface of body surface of body Houses pituitary glandHouses pituitary gland Located in MSP of cranium ¾Located in MSP of cranium ¾ anterior and anterior and

superior to EAMsuperior to EAM



Tuberculum sellae = anterior border of sella Tuberculum sellae = anterior border of sella Dorsum sellae = posterior border of sella Dorsum sellae = posterior border of sella Posterior clinoid processes = top borders of Posterior clinoid processes = top borders of

dorsumdorsum



Clivus = slanted area of bone posterior and Clivus = slanted area of bone posterior and inferior to dorsum inferior to dorsum Continuous with basilar area of occipitalContinuous with basilar area of occipital Supports pons of the brainSupports pons of the brain

Optic groove extends across anterior portion Optic groove extends across anterior portion of tuberculum sellaeof tuberculum sellae Groove ends on each side at the optic canalGroove ends on each side at the optic canal



Optic canal = opening into the apex of orbit Optic canal = opening into the apex of orbit for transmission of optic nerve and for transmission of optic nerve and ophthalmic artery ophthalmic artery Actual opening is termedActual opening is termed optic foramenoptic foramen



Lesser wings arise from anterior and superior Lesser wings arise from anterior and superior portion of body and lie horizontally on each portion of body and lie horizontally on each sideside Form posteromedial portion of orbital roofs, the Form posteromedial portion of orbital roofs, the

posterior portion of anterior cranial fossa, upper posterior portion of anterior cranial fossa, upper margin of superior orbital fissure, and optic canalsmargin of superior orbital fissure, and optic canals

Medial ends form the anterior clinoid processesMedial ends form the anterior clinoid processes



Greater wings arise from sides of body and Greater wings arise from sides of body and curve laterally, posteriorly, anteriorly, and curve laterally, posteriorly, anteriorly, and superiorlysuperiorly Form part of middle cranial fossa and Form part of middle cranial fossa and

posterolateral walls of orbitposterolateral walls of orbit



Three paired foramina situated on greater Three paired foramina situated on greater wingswings RotundumRotundum OvaleOvale Spinosum Spinosum

Pterygoid processes arise from lateral Pterygoid processes arise from lateral portions of inferior surface of body and medial portions of inferior surface of body and medial portions of inferior surfaces of greater wingsportions of inferior surfaces of greater wings



Pterygoids articulate with Pterygoids articulate with Palantine bones anteriorly Palantine bones anteriorly Vomer as part of the nasal cavityVomer as part of the nasal cavity

Sphenoid articulates with each of the other Sphenoid articulates with each of the other seven bones of the cranium and the zygomaseven bones of the cranium and the zygoma



Lateral view


Occipital BoneOccipital Bone

Situated at posteroinferior part of craniumSituated at posteroinferior part of cranium Forms posterior half of cranial base and Forms posterior half of cranial base and

greater portion of posterior cranial fossagreater portion of posterior cranial fossa Has four partsHas four parts

SquamaSquama Two occipital condylesTwo occipital condyles Basilar portionBasilar portion



Foramen magnum = large opening through Foramen magnum = large opening through which the medulla oblongata passes as it which the medulla oblongata passes as it exits craniumexits cranium

External occipital protuberance = prominent External occipital protuberance = prominent process on squama process on squama Also called inion Also called inion Corresponds to internal occipital protuberanceCorresponds to internal occipital protuberance



Occipital condyles = project anteriorly from Occipital condyles = project anteriorly from each side of squamaeach side of squama Fuse at basilar portion to complete foramen Fuse at basilar portion to complete foramen

magnummagnum Articulates with the two parietals, the two Articulates with the two parietals, the two

temporals, the sphenoid, and the atlas (C1)temporals, the sphenoid, and the atlas (C1)



Posterior view



Lateral view


Temporal BonesTemporal Bones

Situated on each side of cranial base Situated on each side of cranial base between greater wings of sphenoid and between greater wings of sphenoid and occipital boneoccipital bone

Form large part of middle cranial fossa and a Form large part of middle cranial fossa and a small part of posterior cranial fossasmall part of posterior cranial fossa



Consist of Consist of Squamous portionSquamous portion Tympanic portionTympanic portion Styloid processStyloid process Zygomatic processZygomatic process Petromastoid portion which contain the organs for Petromastoid portion which contain the organs for

hearing and equilibriumhearing and equilibrium



Squamous portion = thin, upper portion of Squamous portion = thin, upper portion of temporal bonetemporal bone Forms part of side wall of cranium Forms part of side wall of cranium

Zygomatic process = prominent arched Zygomatic process = prominent arched process that projects anteriorly to articulate process that projects anteriorly to articulate with zygoma and complete the zygomatic with zygoma and complete the zygomatic archarch



Articular tubercle = located on inferior border Articular tubercle = located on inferior border of zygomatic process of zygomatic process Forms anterior boundary of mandibular fossaForms anterior boundary of mandibular fossa

Mandibular fossa = receives condyle of Mandibular fossa = receives condyle of mandible to form temporomandibular joint mandible to form temporomandibular joint (TMJ)(TMJ)



Tympanic portion = located below squama Tympanic portion = located below squama and in front of petromastoid portionand in front of petromastoid portion Forms anterior wall, inferior wall and part of Forms anterior wall, inferior wall and part of

posterior walls of the EAMposterior walls of the EAM Styloid process = slender, pointed bone Styloid process = slender, pointed bone

projecting inferiorly, anteriorly, and slightly projecting inferiorly, anteriorly, and slightly medially from inferior surface of tympanic medially from inferior surface of tympanic portionportion



Petromastoid portion combines petrous and Petromastoid portion combines petrous and mastoid portionsmastoid portions Forms the inferior, posterior part of the temporal Forms the inferior, posterior part of the temporal

bonebone Articulates with parietal bone at its superior border Articulates with parietal bone at its superior border

and with occipital bone at its posterior borderand with occipital bone at its posterior border Usually contains air cells, which vary greatly in Usually contains air cells, which vary greatly in

size, number, and pneumatizationsize, number, and pneumatization



Mastoid process = conical process projecting Mastoid process = conical process projecting from mastoid portionfrom mastoid portion

Petrous portion projects medially and Petrous portion projects medially and anteriorly between greater wing of sphenoid anteriorly between greater wing of sphenoid and occipital boneand occipital bone Also called petrous pyramid Also called petrous pyramid Conical or pyramidal in shapeConical or pyramidal in shape Thickest and densest portion of craniumThickest and densest portion of cranium Contains the organs of hearing and balanceContains the organs of hearing and balance



Auditory ossicles = bones of middle earAuditory ossicles = bones of middle ear MalleusMalleus IncusIncus Stapes Stapes

Temporal bone articulates with the parietal, Temporal bone articulates with the parietal, occipital, sphenoid, zygoma, and mandibleoccipital, sphenoid, zygoma, and mandible



Lateral view



Anterior view


Procedural ConsiderationsProcedural Considerations

Skull topographySkull topography Skull morphologySkull morphology General body positionGeneral body position CleanlinessCleanliness Radiation protectionRadiation protection


Skull TopographySkull Topography

GlabellaGlabella Inner canthusInner canthus Outer canthusOuter canthus NasionNasion Infraorbital marginInfraorbital margin AcanthionAcanthion

GonionGonion Mental pointMental point External auditory External auditory

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

(TEA)(TEA)

Be able to locate the following landmarks:


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


Radiographic LandmarksRadiographic Landmarks

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

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 EAMFrom mental point (center of chin) to EAM



Radiographic positioning guidelines are Radiographic positioning guidelines are based on mesocephalic skull size and shapebased on mesocephalic skull size and shape

Adjustments to centering and CR and/or part Adjustments to centering and CR and/or part angulation may be required when working angulation may be required when working with patients with atypical skull shapeswith patients with atypical skull shapes


General Body PositionGeneral Body Position

Patient may be examined in upright or Patient may be examined in upright or recumbent positionsrecumbent positions

General body position is especially important General body position is especially important in hyposthenic, asthenic, and hypersthenic in hyposthenic, asthenic, and hypersthenic body typesbody types


General Body PositionGeneral Body Position

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

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


Hyposthenic/Asthenic PatientsHyposthenic/Asthenic Patients


Hypersthenic PatientsHypersthenic Patients


CleanlinessCleanliness

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

Cranial procedures require direct contact of Cranial procedures require direct contact of patient’s face with VBSpatient’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 patients Shield gonads/abdomen of pediatric patients

and those of reproductive ageand those of reproductive age Shield thyroid and thymus of pediatric patient Shield thyroid and thymus of pediatric patient

when doing so will not interfere with when doing so will not interfere with demonstration of anatomy of interestdemonstration of anatomy of interest

Good communication and positioning skills Good communication and positioning skills reduce chance of need for repeat radiographsreduce chance of need for repeat radiographs


Patient PreparationPatient Preparation

Remove all radiopaque artifactsRemove all radiopaque artifacts EyeglassesEyeglasses Dentures and partial platesDentures and partial plates Hearing aidsHearing aids JewelryJewelry Wigs/hairpiecesWigs/hairpieces Hairpins, barrettes, and pony tail holdersHairpins, barrettes, and pony tail holders False eyesFalse eyes


Essential Projections: CraniumEssential Projections: Cranium

Lateral Lateral Right and left lateral positionsRight and left lateral positions Dorsal decubitus positionDorsal decubitus position

PAPA PA axial (Caldwell method)PA axial (Caldwell method) APAP AP axialAP axial AP axial (Towne method)AP axial (Towne method)


Essential Projections: CraniumEssential Projections: Cranium

PA axial (Haas method)PA axial (Haas method) Submentovertical (SMV)Submentovertical (SMV)

For cranial baseFor cranial base


Lateral ProjectionLateral Projection

Patient positionPatient position Seated upright or semiproneSeated upright or semiprone

Part positionPart position MSP of head parallel to IRMSP of head parallel to IR IPL perpendicularIPL perpendicular IOML parallel to transverse axis of cassetteIOML parallel to transverse axis of cassette



CRCR Perpendicular to center of IRPerpendicular to center of IR Enters 2Enters 2 superior to EAM superior to EAM



Patient positionPatient position Dorsal decubitusDorsal decubitus

Part positionPart position Elevate head on radiolucent support to center to Elevate head on radiolucent support to center to

vertical IRvertical IR MSP of head verticalMSP of head vertical IPL perpendicular to IRIPL perpendicular to IR IOML parallel to transverse axis of cassetteIOML parallel to transverse axis of cassette



CRCR Horizontal and perpendicular to center of IRHorizontal and perpendicular to center of IR Enters 2Enters 2 superior to EAM superior to EAM



Patient positionPatient position Supine or semisupineSupine or semisupine

Part positionPart position Elevate head on radiolucent support to place MSP Elevate head on radiolucent support to place MSP

parallel and IPL perpendicularparallel and IPL perpendicular Turn head toward side of interestTurn head toward side of interest



CRCR Perpendicular to center of IRPerpendicular to center of IR Enters 2Enters 2 superior to EAM superior to EAM


PA/PA Axial (Caldwell)PA/PA Axial (Caldwell)

Patient positionPatient position Seated erect or proneSeated erect or prone MSP centered to midline MSP centered to midline Forehead and nose resting on table or upright Forehead and nose resting on table or upright

BuckyBucky Part positionPart position

OML perpendicular to IR plane OML perpendicular to IR plane MSP perpendicular to IRMSP perpendicular to IR IR centered to nasionIR centered to nasion


PA/PA Axial (Caldwell)PA/PA Axial (Caldwell)

CR for PA projectionCR for PA projection PerpendicularPerpendicular Exits nasionExits nasion

CR for PA axial (Caldwell)CR for PA axial (Caldwell) Angled 15 degrees caudadAngled 15 degrees caudad Exits nasionExits nasion


AP/AP Axial ProjectionAP/AP Axial Projection

Note: Provides similar but magnified image Note: Provides similar but magnified image when patient cannot be positioned for PA or when patient cannot be positioned for PA or

PA axial projection.PA axial projection. Patient and part positionPatient and part position

SupineSupine MSP centered to midlineMSP centered to midline MSP and OML perpendicular to IRMSP and OML perpendicular to IR



CRCR Perpendicular or 15 degrees cephalad for AP axial Perpendicular or 15 degrees cephalad for AP axial

projectionprojection Enters nasionEnters nasion


AP Axial (Towne Method)AP Axial (Towne Method)

Patient and part positionPatient and part position Supine or seated erectSupine or seated erect MSP centered to midlineMSP centered to midline MSP perpendicularMSP perpendicular OML or IOML perpendicularOML or IOML perpendicular

IR top border level with skull vertexIR top border level with skull vertex IR center at or near foramen magnumIR center at or near foramen magnum



CRCR Directed through foramen magnumDirected through foramen magnum OML – 30 degrees caudalOML – 30 degrees caudal IOML – 37 degrees caudalIOML – 37 degrees caudal


PA Axial (Haas)PA Axial (Haas)

Patient positionPatient position Prone or seated uprightProne or seated upright MSP centered to midlineMSP centered to midline Shoulders in same horizontal planeShoulders in same horizontal plane

Part positionPart position Forehead and nose on tableForehead and nose on table MSP perpendicularMSP perpendicular OML perpendicular to IROML perpendicular to IR



CRCR Directed cephalad at angle of 25 degrees to OMLDirected cephalad at angle of 25 degrees to OML Enters at a point 1.5Enters at a point 1.5 (3.8 cm) below external (3.8 cm) below external

occipital protuberanceoccipital protuberance Exits 1.5Exits 1.5 (3.8 cm) superior to nasion (3.8 cm) superior to nasion


SMV Projection (SchSMV Projection (Schüüller)ller)

Patient positionPatient position Seated upright or supineSeated upright or supine Torso elevated if supineTorso elevated if supine

Part positionPart position MSP centered to midlineMSP centered to midline IOML parallel with IRIOML parallel with IR MSP perpendicular to IRMSP perpendicular to IR


SMV Projection (Schüller)SMV Projection (Schüller)

CRCR Through sella turcica perpendicular to IOMLThrough sella turcica perpendicular to IOML Enters MSP of throat between angles of mandibleEnters MSP of throat between angles of mandible Passes through a point ¾Passes through a point ¾ (1.9 cm) anterior to (1.9 cm) anterior to

level of EAMlevel of EAM Center IR to CRCenter IR to CR


Essential Projections: Essential Projections: Temporal BoneTemporal Bone

Axiolateral oblique (modified Law)Axiolateral oblique (modified Law) Axiolateral oblique (Stenvers)Axiolateral oblique (Stenvers) Axiolateral oblique (Arcelin)Axiolateral oblique (Arcelin)


Axiolateral Oblique (Modified Law)Axiolateral Oblique (Modified Law)

Patient positionPatient position Prone or seated uprightProne or seated upright Tape auricle forwardTape auricle forward

Part positionPart position Place head in true lateral position with affected Place head in true lateral position with affected

side closer to IRside closer to IR IOML parallel with IRIOML parallel with IR IPL perpendicular to IRIPL perpendicular to IR MSP angled 15 degrees toward IRMSP angled 15 degrees toward IR


Axiolateral Oblique (Modified Law)Axiolateral Oblique (Modified Law)

CRCR Angled 15 degrees caudad to midpoint of IRAngled 15 degrees caudad to midpoint of IR Exits mastoid tip closer to IR about 1Exits mastoid tip closer to IR about 1 (2.5 cm) (2.5 cm)

posterior to EAMposterior to EAM Enters 2Enters 2 (5 cm) posterior to and superior to (5 cm) posterior to and superior to

upper EAMupper EAM


Axiolateral Oblique (Stenvers)Axiolateral Oblique (Stenvers)

Patient positionPatient position Prone or seated uprightProne or seated upright

Part positionPart position Rest head on forehead, nose, and cheek with side Rest head on forehead, nose, and cheek with side

of interest on IRof interest on IR IOML parallel with transverse axis of IRIOML parallel with transverse axis of IR MSP at 45-degree angle from IRMSP at 45-degree angle from IR


Axiolateral Oblique (Stenvers)Axiolateral Oblique (Stenvers)

CRCR Angled 12 degrees cephaladAngled 12 degrees cephalad Enters about 3Enters about 3 to 4 to 4 (7.6 to 10 cm) posterior and (7.6 to 10 cm) posterior and

½½ (1.3 cm) inferior to upside EAM (1.3 cm) inferior to upside EAM Exits 1Exits 1 (2.5 cm) anterior to downside EAM (2.5 cm) anterior to downside EAM IR and CR centeredIR and CR centered


Axiolateral Oblique Temporal Bone Axiolateral Oblique Temporal Bone (Arcelin)(Arcelin)

Patient positionPatient position SupineSupine MSP centered to midlineMSP centered to midline

Part positionPart position Rotate face away from side of interest to place Rotate face away from side of interest to place

MSP at 45-degree angle with plane of IRMSP at 45-degree angle with plane of IR IOML perpendicular to IRIOML perpendicular to IR



CRCR Angled 10 degrees caudadAngled 10 degrees caudad Enters temporal area at 1Enters temporal area at 1 (2.5 cm) anterior to (2.5 cm) anterior to

EAM and ¾EAM and ¾ (1.9) cm above it (1.9) cm above it Center IR and CRCenter IR and CR


Essential Projections: Optic Canal and Essential Projections: Optic Canal and ForamenForamen

Parietoorbital oblique (Rhese method)Parietoorbital oblique (Rhese method)


Parietoorbital Oblique (Rhese)Parietoorbital Oblique (Rhese)

Patient positionPatient position Semiprone or seated uprightSemiprone or seated upright

Part positionPart position Center affected orbit to center of IRCenter affected orbit to center of IR Rest zygoma, nose, and chin on table or upright Rest zygoma, nose, and chin on table or upright

BuckyBucky AML perpendicular to IRAML perpendicular to IR MSP forms 53-degree angle with IR planeMSP forms 53-degree angle with IR plane



CRCR Perpendicular to IR centerPerpendicular to IR center Enters 1Enters 1 (2.5 cm) superior and posterior to (2.5 cm) superior and posterior to

upside TEupside TE Exits orbit closer to IRExits orbit closer to IR


Lesson 2Lesson 2

Image CritiqueImage Critique

Slide 96


Lateral ProjectionsLateral Projections

Entire cranium without rotation or tiltEntire cranium without rotation or tilt Superimposed orbital roofs and greater Superimposed orbital roofs and greater

wings of sphenoidwings of sphenoid Superimposed mastoid regions and EAMsSuperimposed mastoid regions and EAMs Superimposed TMJsSuperimposed TMJs Sella turcica in profileSella turcica in profile Penetration of parietal regionPenetration of parietal region No overlap of C-spine by mandibleNo overlap of C-spine by mandible


PA ProjectionPA Projection

Entire cranial perimeter showing three tables Entire cranial perimeter showing three tables of squamous boneof squamous bone

No rotationNo rotation Equal distance from lateral borders of skull to Equal distance from lateral borders of skull to

lateral border of orbitslateral border of orbits Symmetric petrous ridgesSymmetric petrous ridges


PA ProjectionPA Projection

Petrous ridges fill orbitsPetrous ridges fill orbits Penetration of frontal bone without excessive Penetration of frontal bone without excessive

density at lateral borders of skulldensity at lateral borders of skull


PA Axial (Caldwell Method)PA Axial (Caldwell Method)

Same as for PA projection, exceptSame as for PA projection, except Petrous ridges demonstrated in lower one third Petrous ridges demonstrated in lower one third

of orbitof orbit



Same as PA and PA axial projectionsSame as PA and PA axial projections Anatomy more magnified in AP and AP axial Anatomy more magnified in AP and AP axial

projectionsprojections



No rotationNo rotation Equal distance from lateral border of skull to Equal distance from lateral border of skull to

lateral margin or foramen magnumlateral margin or foramen magnum Symmetric petrous ridgesSymmetric petrous ridges

Dorsum sellae and posterior clinoid Dorsum sellae and posterior clinoid processes visible within foramen magnumprocesses visible within foramen magnum

Penetration of occipital bone without Penetration of occipital bone without excessive density at parietalsexcessive density at parietals



Projection of dorsum sellae and posterior Projection of dorsum sellae and posterior clinoid processes within foramen magnumclinoid processes within foramen magnum

Equal distance from lateral border of skull to Equal distance from lateral border of skull to lateral margin of foramen magnumlateral margin of foramen magnum

Symmetric petrous pyramidsSymmetric petrous pyramids Entire craniumEntire cranium



No rotation or tiltNo rotation or tilt Equal distance from lateral border of skull to Equal distance from lateral border of skull to

mandibular condylesmandibular condyles Symmetric petrous pyramids Symmetric petrous pyramids

Penetration sufficient to demonstrate Penetration sufficient to demonstrate structures of cranial basestructures of cranial base



Superimposition of mental protuberance over Superimposition of mental protuberance over anterior frontal bone, indicating full neck anterior frontal bone, indicating full neck extensionextension

Mandibular condyles anterior to petrous Mandibular condyles anterior to petrous pyramidspyramids



Superimposition of mental protuberance over Superimposition of mental protuberance over frontal bone – indicates full neck extensionfrontal bone – indicates full neck extension

Condyles of mandible anterior to petrous Condyles of mandible anterior to petrous pyramidspyramids


Axiolateral Oblique Temporal Bone Axiolateral Oblique Temporal Bone (Modified Law)(Modified Law)

Mastoid process closer to IRMastoid process closer to IR Air cells centered to IRAir cells centered to IR Opposite mastoid process inferior and Opposite mastoid process inferior and

anterior mastoid of interestanterior mastoid of interest Auricle of ear not superimposing mastoidAuricle of ear not superimposing mastoid Superimposition of IAM and EAMSuperimposition of IAM and EAM TMJ visible anterior to mastoid processTMJ visible anterior to mastoid process Close beam restrictionClose beam restriction


Axiolateral Oblique Temporal Bone Axiolateral Oblique Temporal Bone (Stenvers)(Stenvers)

Petromastoid portion in profilePetromastoid portion in profile Lateral border of skull to lateral border of orbitLateral border of skull to lateral border of orbit Petrous ridge extended to a point about two Petrous ridge extended to a point about two

thirds up lateral border of orbitthirds up lateral border of orbit


Axiolateral Oblique Temporal Bone Axiolateral Oblique Temporal Bone (Stenvers)(Stenvers)

Mastoid process in profile below craniumMastoid process in profile below cranium Posterior margin of mandibular ramus Posterior margin of mandibular ramus

superimposing lateral border of C-spinesuperimposing lateral border of C-spine Mandibular condyle projecting over atlas near Mandibular condyle projecting over atlas near

petrosapetrosa Close beam restrictionClose beam restriction



Petromastoid portion in profilePetromastoid portion in profile Lateral border of skull to lateral border of orbitLateral border of skull to lateral border of orbit Petrous ridge lying horizontal about two thirds Petrous ridge lying horizontal about two thirds

up lateral border of orbitup lateral border of orbit



Mastoid process in profile below craniumMastoid process in profile below cranium Posterior margin of mandibular ramus Posterior margin of mandibular ramus

superimposing lateral border of C-spinesuperimposing lateral border of C-spine Mandibular condyle projecting over atlas near Mandibular condyle projecting over atlas near

petrosapetrosa Close beam restrictionClose beam restriction



Optic canal and foramen visible at end of Optic canal and foramen visible at end of sphenoid ridge in inferior and lateral quadrant sphenoid ridge in inferior and lateral quadrant of orbitof orbit

Entire orbital rimEntire orbital rim Supraorbital margins lying in same horizontal Supraorbital margins lying in same horizontal

lineline Close beam restriction to orbitClose beam restriction to orbit

skull & cranial bones extra handout by dr. mohsen dashti imaging procedures 362 march 15 &...

Documents

derived items

temporalmosby items

affiliate of elsevier

parietal bonesmosby

calvaria floormosby

cranial floorinternally

facial bones

separate bones