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!!!