A sinus x-ray is a picture of the air-filled cavities in the front of the skull.

This test is performed when symptoms of sinusitis or other sinus disorders are present.

X-rays are a form of electromagnetic radiation -- like light, but of higher energy. They can pass through the body to form an image on film. Structures that are dense (such as bone) look white, air looks black, and other structures are shades of gray.

A sinus x-ray is taken in a hospital radiology department or your health care provider's office. You will be asked to sit in a chair so that any fluids in the sinus may be easily seen on the pictures. The technician may place your head in different positions as the pictures are taken.

Tell your doctor if you are pregnant. Remove all jewelry.

Generally, there is little or no discomfort associated with x-rays.