Lymph vessel

Overview
In anatomy, lymph vessels are thin walled, valved structures that carry lymph. As part of the lymphatic system, lymph vessels are complimentary with the vascular system. In contrast to the vascular system, which carries blood under pressure to the entire body, lymph is not under pressure and is propelled in a passive fashion, assisted by the aforementioned valves. Fluid that leaks from the vascular system is returned to general circulation via lymphatic vessels.

Generally, lymph flows away from the tissues to lymph nodes and eventually to either the right lymphatic duct or the largest lymph vessel in the body, the thoracic duct. These vessels drain into the right and left subclavian veins respectively.

Function
Lymph vessels act as a reservoir from plasma and other substances including cells that leaked from the vascular system and transport lymph fluid back from the tissues to the circulatory system. Without functioning lymph vessels, lymph cannot be effectively drained and edema typically results.