Lecture (27)

Radiography of cranial Bones

– Basic0°Occipito -frontal 15° Occipito-frontal ( Caldwell)

– AP Axial 30° Fronto- Occipital ( Townes)

– Sub-mento vertical ( SMV)

Trauma Series Craniu

0° Fronto occipital 20° Fronto occipital Lateral ( Horizontal Beam )

Cranium (Sella Turcica) BasicLateral

AP Axial ( Townes )

Skull Basic projections ( Cranium Bones )

– Basic• 0°Occipito -frontal • 15° Occipito-frontal ( Caldwell)

• AP Axial 30° Fronto- Occipital ( Townes)• Sub-mento vertical ( SMV)

0° Occipito- frontal

• Exposure factors

KV mAs FFD Focus Grid Film/Screen combination

80 40 100 Fine Yes Regular

Patient PositionPatient prone or sits erect facing the bucky.Part PositionRest patient’s nose and forehead against the bucky.Align midsagittal plane perpendicular to and in line with the midline of bucky and central ray.

Tuck chin in to bring the OML 90° to film.Centre bucky to Glabella

• Central Ray• Horizontally & perpendicular to film holder• Centre Point • Exit through the Glabella• Anatomy Demonstrated• Frontal bone, crista galli, internal auditory canals,

frontal and ethmoid sinuses, • petrous ridges, greater and lesser wings of sphenoid

bone

15° Occipito-frontal (Caldwell)

• Exposure factors

KV mAs FFD Focus Grid Film/Screen combination

80 40 100 Fine Yes Regular

Patient PositionPatient Prone or sits erect facing the bucky.

Part PositionRest patient’s nose and forehead against the bucky.Align midsagittal plane perpendicular to and in line with the midline of bucky and central ray.Tuck chin in to bring the OML 90° to film.Centre bucky to Nasion

Central RayAngled 15° Caudally Centre PointExit through the NasionAnatomy DemonstratedFrontal bone, crista galli, Orbital margin, frontal and ethmoid sinuses, petrous ridges, greater and lesser wings of sphenoid.Petrous pyramids projected into lower 1/3 of the orbits

Basic Skull Projections30° Fronto Occipital (Townes)

• Exposure factors

KV mAs FFD Focus Grid Film/Screen combination

85 40 100 Fine Yes Regular

.Patient PositionPatient supine or sits erect A.P. against the buckyPart PositionAlign midsagittal plane perpendicular to and in line with the midline of bucky and central ray.Tuck chin in to bring the OML 90° to film.

Central RayAngled 30° Caudallycentre PointIn the midline to a point 6 cm above the Nasion.

Anatomy Demonstrated

• Occipital bone, petrous pyramids, foramen magnum, dorsum sellae and posterior clinoids

• Dorsum sella and posterior clinoids are projected into the foramen magnum.

Basic Skull Projections

Lateral (Cranium) • Exposure factors

KV mAs FFD Focus Grid Film/Screencom

bination

85 40 100 Fine Yes RegularPatient PositionPatient recumbent semi prone or sits erect facing the bucky,Part Position Rotate head to the side in question, to bring the median Sagittal plane parallel to the film.The angle of the OMB is adjusted for maximum patient comfort.The Interpupillary line should be parallel to the floor.Central RayPerpendicular to film holder Centre PointTo a point 2cm superior and 2cm anterior to the EAM.

Anatomy Demonstrated

• Lateral aspect of cranium nearest to the film, dorsum sella, anterior and posterior clinoids, greater and lesser wings of sphenoid bone.

• Mandibular rami, orbital roofs, E.A.M.s and wings of sphenoid bone superimposed.

• Sella turcica seen in profile.

Basic Skull ProjectionsSub-mento vertical ( SMV)

• Exposure factors

KV mAs FFD Focus Grid Film/Screen combinati

on

85 40 100 Fine Yes Regular

Patient PositionPatient supine or sits erect, with his back to the buckyPart Position

Take care with this technique; it is not suitable for trauma patientsa small pillow is placed behind the shoulders and the patient extends the neck until the orbital Meatal baseline is parallel to the filmthe Interpupillary line parallel to the floor and the median sagittal plane at 90 degrees to the film Apply thyroid protection with lead rubber

• Central Ray

• Horizontally & perpendicular to film holder • Centre Point• Midway between the angles of the mandible

Anatomy Demonstrated

Base of skull and associated foramina

Cranium Bones (Trauma Series)

0° Fronto occipital 20° Fronto occipital Lateral ( Horizontal Beam )

0° Fronto occipital • Exposure factors

KV mAs FFD Focus Grid Film/Screen combination

85 40 100 Fine Yes Regular

Patient PositionThe patient lies supine on the trolley or x-ray tablePart Position

The midsagittal plane centred to centre of the table.The patients head is positioned so that the Interpupillary line is parallel to the film.The neck is flexed depressing the chin until the radiographic baseline (OMBL) is at 90 degrees to the film, * Not possible if there is a possible cervical injury)A small pad may be needed under the occipital or beneath the cassette

Central Ray Perpendicular to film holderCentre PointTo the Glabella

• Anatomy Demonstrated

Frontal bone, crista galli, internal auditory canals, frontal and ethmoid sinuses, petrous ridges, greater and lesser wings of sphenoid bone

Exposure factors

20° Fronto occipital

KV mAs FFD Focus Grid Film/Screen combination

85 40 100 Fine Yes Regular

Patient PositionThe patient lies supine on the trolley or x-ray tablePart PositionThe midsagittal plane centred to centre of the table.The patients head is positioned so that the interpupillary line is parallel to the film.The neck is flexed depressing the chin until the radiographic baseline (OMBL) is at 90 degrees to the film, * Not possible if there is a possible cervical injury)A small pad may be needed under the occipital or beneath the cassette

Central Ray The vertical central ray is angled 20 degrees craniallyCentre PointTo the Glabella

 Anatomy DemonstratedFrontal bone, crista galli, Orbital margin, frontal and ethmoid sinuses, petrous ridges, greater and lesser wings of sphenoid.Petrous pyramids projected into lower 1/3 of the orbits

Exposure factors

Lateral (Horizontal Beam)

KV mAs FFD Focus Grid Film/Screen combination

80 40 100 Fine Yes RegularPatient PositionThe patient lies supine on the trolley or x-ray tablePart PositionMidsagittal plane aligned central to the table,The head is supported on a small pad, Side of interest nearest the film. the median sagittal plane must be parallel to the Film is placed vertically along side of the head.

• Central Ray • Horizontally & perpendicular to film holder • Centre Point• To a point 2cm superior and 2cm anterior to the EAM• Anatomy Demonstrated• Lateral aspect of cranium nearest to the film, dorsum sella, anterior

and posterior clinoids, greater and lesser wings of sphenoid bone.

• Mandibular rami, orbital roofs, E.A.M.s and wings of sphenoid bone

superimposed.

Cranial Bones (Sella Turcica)

• Basic– Lateral

• AP Axial ( Townes )

BasicLateral

AP Axial ( Townes )

Lateral (Sella) • Exposure factors

KV mAs FFD Focus Grid Film/Screen combination

85 40 100 Fine Yes Regular

Patient PositionPatient recumbent semi prone or sits erect facing the bucky,Part Position Rotate head to the side in questionAlign Interpupillary line perpendicular to bucky surfaceAlign midsagittal plane parallel to bucky surfaceCollimate to field size approximately 4 inches squareSuspend respiration during exposureCentral RayPerpendicular to film holder Centre PointTo a point 2cm superior and 2cm anterior to the EAM.

Anatomy DemonstratedSella turcica Anterior and posterior clinoids processesDorsum sella and clivus

Sella 30° Fronto Occipital (Townes)• Exposure factors

KV mAs FFD Focus Grid Film/Screen combinat

ion

85 40 100 Fine Yes RegularPatient PositionPatient supine or sits erect A.P. against the buckyPart PositionAlign midsagittal plane perpendicular to and in line with the midline of bucky and central ray.Tuck chin in to bring the OML 90° to film.Collimate to field size approximately 4 inches squareSuspend respiration during exposure

Central RayAngled 37° Caudally for dorsum sellae and posterior clinoid processesAngled 30° Caudally for anterior clinoid processesCentre PointIn the midline to a point 1& ½ inch above superciliary archAnatomy DemonstratedDorsum sella, anterior and posterior clinoids processes( Depending on CR angulation)Foramen MagnumOccipital Bone