Lecture (27)

Radiography of cranial Bones

–Basic 0°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) Basic  Lateral  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 KVmAsFFDFocusGridFilm/Screen combination FineYesRegular Patient Position Patient prone or sits erect facing the bucky. Part Position Rest 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 KVmAsFFDFocusGridFilm/Screen combination FineYesRegular Patient Position Patient Prone or sits erect facing the bucky. Part Position Rest 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 Ray Angled 15° Caudally Centre Point Exit through the Nasion Anatomy Demonstrated Frontal 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 Projections 30° Fronto Occipital (Townes) Exposure factors KVmAsFFDFocusGridFilm/Screen combination FineYesRegular.Patient Position  Patient supine or sits erect A.P. against the bucky Part Position 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. Central Ray Angled 30° Caudally centre Point In 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 KVmAsFFDFocusGridFilm/Screenco mbination FineYesRegular Patient Position Patient 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 Ray 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. Sella turcica seen in profile.

Basic Skull Projections Sub-mento vertical ( SMV) Exposure factors KVmAsFFDFocusGridFilm/Screen combinati on FineYesRegular Patient Position  Patient supine or sits erect, with his back to the bucky Part Position Take care with this technique; it is not suitable for trauma patients a small pillow is placed behind the shoulders and the patient extends the neck until the orbital Meatal baseline is parallel to the film the 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 KVmAsFFDFocusGridFilm/Screen combination FineYesRegular Patient Position The patient lies supine on the trolley or x-ray table Part 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 holder Centre Point To 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 KVmAsFFDFocusGridFilm/Screen combination FineYesRegular Patient Position The patient lies supine on the trolley or x-ray table Part 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 The vertical central ray is angled 20 degrees cranially Centre Point To the Glabella Anatomy Demonstrated Frontal 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) KVmAsFFDFocusGridFilm/Screen combination FineYesRegular Patient Position The patient lies supine on the trolley or x-ray table Part Position Midsagittal 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 ) Basic  Lateral  AP Axial ( Townes )

Lateral (Sella) Exposure factors KVmAsFFDFocusGridFilm/Screen combination FineYesRegular Patient Position Patient recumbent semi prone or sits erect facing the bucky, Part Position Rotate head to the side in question Align Interpupillary line perpendicular to bucky surface Align midsagittal plane parallel to bucky surface Collimate to field size approximately 4 inches square Suspend respiration during exposure Central Ray Perpendicular to film holder Centre Point To a point 2cm superior and 2cm anterior to the EAM.

Anatomy Demonstrated Sella turcica Anterior and posterior clinoids processes Dorsum sella and clivus

Sella 30° Fronto Occipital (Townes) Exposure factors KVmAsFFDFocusGridFilm/Screen combinat ion FineYesRegular Patient Position Patient supine or sits erect A.P. against the bucky Part Position 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. Collimate to field size approximately 4 inches square Suspend respiration during exposure

Central Ray Angled 37° Caudally for dorsum sellae and posterior clinoid processes Angled 30° Caudally for anterior clinoid processes Centre Point In the midline to a point 1& ½ inch above superciliary arch Anatomy Demonstrated Dorsum sella, anterior and posterior clinoids processes( Depending on CR angulation) Foramen Magnum Occipital Bone