The lymphatic system has two overarching purposes: draining tissue fluid and macromolecules from the interstitial space back into the blood and mediating the immune response. This is accomplished when substances enter lymphatic vessels, which are distributed throughout the body to form a distinct vascular network that directs them toward the lymph nodes for filtration prior to entering the venous system (Ribatti and Crivellato 2010; Garza et al. 2009). The same description applies to the lower limb, which has two broad classes of lymphatic vessels (Garza et al. 2009): superficial (primary) and secondary. A major characteristic of superficial (primary) lymphatic vessels is their reliance on osmotic gradients and hydrostatic pressure differences to facilitate interstitial fluid/protein movement and absorption, as their walls lack smooth muscles. In contrast, the walls of secondary lymphatic vessels have a muscular component (albeit significantly thinner than those in arteries and veins). Another defining feature of secondary lymphatic vessels is the presence of valves that assist in afferent fluid movement. Despite the clear differences between the two systems, they cooperate with each other. The primary lymphatics collect fluid, protein, cells, and debris for transport via the secondary lymphatics, which propel fluid unidirectionally to lymph nodes and eventually the venous system (Mortimer and Rockson 2014; Petrova et al. 2004).