Some of the Extraoral radiography are given below:
Diagnostic ultrasound extraoral radiography, which makes use of sound waves to generate an image is commonly used in obstetrics. Of late, ultrasound has found its application in the examination of the floor of the mouth and salivary glands.
A postero-auterior view or PA view of extraoral radiography is taken with a 8 x 10 inches screen film combination. As the name implies, the central x-ray beam is directed from behind and through the skull. It is used to evaluate the skull for am pathology, trauma or developmental anomalies. It gives a good view of the skull in the medio-lateral direction.
Paranasal sinus view
Paranasal sinus view or PNS view or Waters projection extraoral radiography is a variation of the PA view and is mainly indicated in the visualization of paranasal sinuses, orbits and zygomaticofrontal sutures. In this projection, the central x-ray beam enters the skull tangentially to exit at the chin region. This view is taken with a 8x 10 inches screen film combination.
Reverse town projection
This extraoral radiography is taken on a 8 x 10 inches screen film combination. It is indicated in suspected cases condylar neck fractures. This radiograph is taken in an open mouth position. This projection is similar to the PNS view with the difference that the head is tilted downward.
A submentovertex view extraoral radiography is also taken with a 8 x 10 inches screen film combination. This radiograph is taken by directing the central x-ray beam through the floor of the mouth to exit at the vertex of the skull. This radiograph helps in the visualization of the condyles, sphenoid sinus and curvature of the mandible.
Direct digital radiography
Direct digital radiograph or digital intra-oral radiography is popularly called radio-visiography (RVG). Though this technique makes use of the X-ray machine, it differs from the conventional radiographic technique in that here an intensifying screen charged coupled device (CCD) is used as the image receptor system.
The signal from the CCD is digitized to form an image in the monitor In this technique the image is obtained immediately and contrast enhancement is possible to achieve better results. The image obtained can also be stored in the computer for future reference. It is also possible to obtain print outs from the image recorded in the monitor in extraoral radiography.