Skull 

 SMV
Indications for imaging
Trauma, base of skull and associated foramina.

 

Anatomy  Demonstrated
Base of skull and associated foramina.


Skull SMV Anatomy
Meschan, I. 1955 An Atlas of Normal Radiographic Anatomy Saunders, London

 

Basic Patient Position
Take care with this technique, the patient may suffer vaso vagal reactions or vertigo, it is not suitable for trauma patients.
The patient sits erect with their back to the erect bucky, 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 interpupilary line parallel to the floor and the median saggital plane at 90 degrees to the film.


 Skull SMV Patient Position
Based on Movin & Karlsson 1975 Skeletal projections for Diagnostic Radiology Lippincott  

 
Radiation protection
Direct lead rubber thyroid protection advisable.

 
Central Ray
The horizontal central ray is centered midway between the angles of the mandible.

 
Exposure Factors
Kv mAS FFD (cm) Grid Focus AEC Cassette
85 70 100 Yes Broad Yes 18 x 24 cm

 
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 entire skull should be visualised,
The symmetrical structures should be projected symmetrically about the midline.
The mandibular symphysis is projected over the frontal bone and the mandibular condyles anterior to the petrous bones, the foramen magnum should be projected almost circular.



 Skull SMV Radiograph
Related Projections
Skull PA 20
Skull Reverse Townes
Skull Lateral
Additional modalities
CT
MRI