A tunnelled line is inserted via the internal jugular vein. Its tip (arrow) lies at the cavoatrial junction - the junction of the superior vena cava and the right atrium.
The entry site (E) is where the line enters the vein. The red section is therefore intravenous. The exit site (X) is where it exits the skin. Between these two points the line is tunnelled through the subcutaneous tissues over the front of the chest wall (orange section).
The purpose of inserting a tunnelled line is so that it can stay in situ for a long period of time. This patient with cancer was receiving long term chemotherapy, via the two access points which lie outside the skin (green section).