During the ultrasound examination, the patient is lying down, standing or sitting with legs lowered. The doctor covers the skin of the examined person's legs with a special gel and then places the ultrasound head on it. The image obtained thanks to the reflection of ultrasonic waves from the tissues is observed on the monitor screen. The doctor moves the probe along the course of the following veins, assessing them in very small sections (every 1 cm). Ultrasound examination includes the assessment of deep and superficial veins along the entire length of the lower limb up to the groin. Sometimes it is also necessary to examine the veins in the pelvis and abdominal cavity.