Depending on the reason for the ultrasound exam, an instrument called a proctoscope may be inserted into the rectum. The ultrasound transducer is then inserted either through the proctoscope or by itself.

A transducer sends and receives sound waves that are used to create images on the screen. An additional screen is usually available so that you may watch as the doctor carefully examines the area.

The ultrasound allows the physician to visualize and stage tumors. Additionally, he can analyze anal sphincter abnormalities and observe the path and depth of various anorectal abnormalities such as anal fistula.