Positioning of skull
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Transcript of Positioning of skull
POSITIONING OF SKULL
DR.S.SAJITH MBBS MD RD
DR.SOMERVELL MEMORIAL MEDICAL COLLEGE
RADIOLOGY DEPARTMENT
Planes
Median sagittal plane
Anthropological plane
Auricular plane
Major body planes used in Skull radiography
Median S agittal Auricular Anthropological
The Median Sagittal plane. A vertical plane dividing the skull into 2
symmetrical right and left halves when viewed from the anterior aspect.
The Anthropological plane This plane splits the skull into upper and lower
halves passing along the anthropological baselines.
The Auricular plane This plane divides the skull into anterior and
posterior compartments along the Auricular lines.
Lines
Inter orbital line
Infra orbital line
Anthropological baseline
Orbito meatal baseline
Anthropological Orbital Meatal Interpupillary
The Anthropological line The Isometric “Baseline” which runs from the
inferior orbital margin to the upper border of the external auditory meatus (EAM)
The Orbital-Meatal Line The original “Baseline” which runs from the
outer canthus of the eye to the centre of the external auditory meatus
The Interpupillary line The line connects the centres of the orbits and is
at 90 degree to the median sagittal plane.
NOTE: there is a difference of 10 to 15 degrees between the Orbital-Meatal line and the anthropological line.
Basic views
Lateral viewFronto occipital view ( A P view )Fronto occipital with 30 deg caudad ( TOWNE’S
view)Occipito frontal view ( P A view)Occipito frontal with 15 deg caudad
( CALDWELL’S view )Submento vertical view (BASILAR view)Occipito mental view ( WATER’S view)
Lateral view
Position of patient :
Patient sits facing the bucky and the head is then rotated, such that the median sagittal plane is parallel to bucky and inter orbital line is perpendicular to it.
Position the cassette transversely in the erect bucky, such that its upper border is 5 cm above the vertex of the skull
Central ray :
midway between the glabella and the external occipital protuberance to a point approx 5 cm superior to the external auditory meatus.
Essential image characteristics :
The image should contain all cranial bones and the first cervical vertebra.
Should superimpose the floor of anterior cranial fossa and posterior cranial fossa. The sella turcica and clinoid processes should also be superimposed.
Fronto occipital viewPositioning : Patient lies supine on a bucky table. Head is adjusted
to bring the median sagittal plane at right angles to the film.
The external auditory meatuses are equidistance from the cassette
The orbito meatal baseline should be perpendicular to the cassette
Central ray :
Central ray is directed perpendicular to the cassette along the medial sagittal plane and throw nasion.
The field should be set to include the vertex of the skull superiorly and base of the occipital bone inferiorly.
Towne’s view
fronto occipital 30 deg caudad
Positioning same as AP view
Certral ray :
Its angled caudally so it makes 30 deg to the orbito meatal plane
Centre in the midline such that the beam passes midway between external auditory meatuses. This is a point approx 4 cm above the glabella
Essential image characteristics
the sella turcica is projected with in the foramen magnum.
Include all the occipital bone and posterior parts of parietal bone, and the lambdoidal suture should be visualized clearly.
Occipito frontal view
Positioning of patient :Patient is seated facing the erect bucky, so that
the median sagittal plane is with the midline of the bucky and perpendicular to it.
Neck is flexed to bring orbito meatal line perpendicular to the bucky, this can be achieved by ensuring the nose and forehead are in contact with the bucky.
Central ray :Ray is directed perpendicular to the bucky along
the median sagittal plane and at the level of nasion.
Image should include the vertex superiorly and base of occipital bone inferiorly
Caudal angulation : OF 0 deg : the petrous ridges completely
superimposed with orbit
OF 10 deg : the petrous ridges appears in the middle third of the orbit
OF 20 deg : the petrous ridges appears just below the inferior orbital margin.
Caldwell’s view
occipito frontal with 15 deg caudad
Positioning same as occipito frontal view
Central ray :
Ray is directed perpendicular to the bucky alone the median sagittal plane.
The tube is rotated 15 deg caudal to the orbito meatal baseline
Submento vertical viewPositioning of patient :Patient neck is hyperextended to bring the vertex
in contact with the cassette.
The median sagittal plane should be right angle to the cassette.
The orbito meatal plane should be near as possible and parallel to the cassette.
Central ray :
Central ray is perpendicular to orbito meatal line.
Center 1½ inch (4 cm) inferior to the mandibular symphysis
Essential image characteratics :
Should show the angles of mandible clear of the petrous portion of temporal bone.
The formina of the middle cranial fossa should be seen symmetrically either side of the midline.
Occipito mental view WATER’S VIEWPositioning of patient :
The patient is made to sit facing the cassette.
Head is adjusted to bring orbito meatal line to 45 deg to the cassette
The patient’s nose and chin are placed in contact with the midline of cassette.
The patient should open the mouth as wide as possible before exposure.
Central ray :
The ray should is perpendicular to the median sagittal plan.
The ray should be centre to pass throw the base of nose.
Thank you!!!