3-621:

You have had lymph vessels and lymph nodes in the arms or legs examined.

Fluid forms in tissue throughout the body every day. This tissue fluid is the lymph. The lymph is carried around the body by lymph vessels. The lymph vessels run around the entire body and are connected to blood vessels. At some points, there are lymph nodes along the lymph vessels. Pathogens are rendered harmless in the lymph nodes, for example.

The examination involved, initially, injecting a contrast agent. A contrast agent is a fluid. The contrast agent spreads through lymph vessels and lymph nodes. X-ray images are then taken of the arm or leg. The purpose of the contrast agent is to make lymph vessels and lymph nodes visible on the X-ray images.