In this post we shall discuss about Submentovertex – Extraoral View
Radiograph of the base of the skull is taken by Submentovertex – Extraoral View (SMV).
Lesions affecting palate or pterygoid region or base of skull or sphenoidal sinus.
Structures Visible in this view
Odontoid process or atlas
Projection of petrosa
Axial inclination of Mandibular condyles
Perpendicular to the floor
Long axis of film/cassette should be placed vertically
Head of the patient is centered on the casette
Head and neck should be tipped back as far as possible
Vertex of skull should touch cassette
Mid sagittal plane should be perpendicular to the film
Radiographic base line is parallel to film
It is directed perpendicular to the film passing through mid sagittal plane.
Central ray should be perpendicular to an imaginary line joining mandibular first molars
For viewing petroud portion, central ray should be at right angles to film midway between the external auditory meatus.