Embryologic, Histologic, and Anatomic Aspects
The skin is home to an elaborate network of lymphatic vessels that parallels the major blood vascular plexuses but is independent of them. From a superficial plexus of lymphatic capillaries arise progressively thicker-walled lymphatic vessels whose valves constitute a one-way drainage system that directs its contents into the venous circulation. The superficial plexus of lymphatic capillaries is situated in the upper part of the reticular dermis, just beneath the superficial plexus of blood vessels.
The structure of cutaneous lymphatics enables clearance from the dermis of fluids, macromolecules, cells, and foreign material. The twin roles of the lymphatic network as a conduit for Langerhans’ cells and as an exit for macromolecules such as lipids, proteins, and immune complexes make it indispensable for maintenance of homeostasis. When the lymphatic system fails, inevitable consequences are impaired immune function, recurrent infection, and fibroplasia secondary to chronic lymphedema.