It is not just getting from A to B. It is what happens on the way.
Interstitial or Extracellular fluid enters the lymph capillaries via gill like openings. Once within the lymphatic system the fluid that is now called lymph, drains into larger vessels called the lymphatics. These vessels converge to form one of two large vessels call lymphatic trunks, which are connected to veins at the base of the neck
The Lymph in the Head and Neck are assisted by gravity to drain whereas lymph fluid in the arms, legs and abdomen travel through the non-return valve lymph vessels via 5 mechanisms
Skeletal muscle contraction
Valves to prevent backflow
Peristaltic contraction of smooth muscle in walls of lymphatics
Pulsations of nearby arteries
Firstly, skeletal muscles push against the lymph vessels pushing open the upstream end of the lymph valve forcing the fluid into the next chamber. The valve then closes back up preventing the fluid from flowing backwards.
Flow of Lymph toward the
Lymphatic or Thoracic Duct
The lymph fluid then travels via lymph capillaries into larger lymph vessels called lymphatics where smooth muscles add to the force of the skeletal muscles pushing the fluid through each chamber in the larger lymph vessels. This action of the smooth muscles is called peristalsis. The larger lymph vessels travel deeper to the underside of the armpit lymph nodes and on the inner side of the leg travelling to the groin nodes.
As lymph flows through your lymphatic vessels, it passes through lymph nodes. There are about 600 of these small, bean-shaped organs scattered strategically throughout your body. In the lymph nodes, lymph is filtered for bacteria, cancer cells, and other potentially threatening agents.
The fourth way is via thoracic pressure. Located just inferior to the respiratory diaphragm is the Cisterna chyli, a sac like structure that fills with fluid, through deep breathing, expanding and contracting the diaphragm, from the abdominal region into the thoracic duct. The respiratory diaphragm puts the Cisterna chyli under the influence of the volume and pressure changes of the respiratory system so as you inhale increasing the thoracic cage Cisterna chyli experiences the changes of pressure drawing lymph up from your lower extremities back toward the thoracic cavity.