A peripheral intravenous line is inserted in peripheral veins, such as the veins in the arms, hands, legs and feet. Medication administered in this way travels through the veins to the heart, from where it is distributed to the rest of the body through the circulatory system. The size of the peripheral vein limits the amount and rate of medication which can be administered safely. A peripheral line consists of a short catheter inserted through the skin into a peripheral vein. This is usually in the form of a cannula-over-needle device, in which a flexible plastic cannula comes mounted over a metal trocar. Once the tip of the needle and cannula are placed, the cannula is advanced inside the vein over the trocar to the appropriate position and secured. The trocar is then withdrawn and discarded. Blood samples may also be drawn from the line directly after the initial IV cannula insertion.