Indications for imaging
Trauma, But see RCR recommendations.
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Anatomy Demonstrated
Occiput, foramen magnum, dorsum sella. sphenoid bone
Skull Frontal Occipital 30 Anatomy
Meschan, I. 1955 An Atlas of Normal Radiographic
Anatomy Saunders, London
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Basic Patient Position
The patient lies supine on the trolley or x-ray table, the midsaggital
plane central.
The patients head is positioned so that the interpupilary 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 occiput or beneath the
cassette.
Skull Frontal Occipital 30 Patient Position
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Radiation protection
Avoid irradiation of the thyroid region, direct lead rubber
protection my be used.
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Central Ray
The vertical central ray is angled 30 degrees caudally and centered
to a point in the midline 5cm above the nasion to pass through
the external auditary meati. If the baseline cannot be
positioned at 90 degrees to the film the angle between the base
line and the central ray should be maintained at 30 degrees.
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Exposure Factors
| Kv |
mAS |
FFD (cm) |
Grid |
Focus |
AEC |
Cassette |
| 90 |
30 |
100 |
Yes Stationary |
Fine |
No |
24 x 30 cm |
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Evaluation of the Image
ID and anatomical markers must be present and correct in the
appropriate area of the film.
Optimal exposure should penetrate all the bone structures and
contrast should be low enough to visualise fully the bone and
soft tissue structures.
The posterior cranial vault superior to the foramen magnum should be visible.
The dorsum sella should be projected in the almost circular
foramen magnum.
The foramen magnum should be projected centrally within the skull
outline.
Skull Frontal Occipital 30 radiograph
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Related Projections
Skull Occipital Frontal 20
Skull Lateral Horizontal Ray
Skull Sub Mento Vertical
Facial Bones
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Additional modalities
CT
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