The Current Concepts of the Embryology of the Lymphatic System

The overall lymphatic system is the major factor in maintaining the integrity of our cellular immunity as well as in playing a role in lipid metabolism and hormone transport. There is a major interest in the ability of certain tumors to induce lymphangiogenesis and the potential impact that this may have on treatment. The lymph nodes also play a significant role as prognosticators of survival in cancer patients, and, the more complete our knowledge of this critical system, the better one can appreciate its complexity and function. The best place to start is with the origin of the lymphatic vasculature. In the head and neck, this vascular network arises primarily from the anterior cardinal veins as well as from the intersomitic veins and the superficial venous plexus. Thus, to fully understand lymphangiogenesis, it is necessary to briefly review vasculogenesis and angiogenesis to appreciate how these vessels arise. This review examined the current concepts of the development first of the vascular system and then of the lymphatic system. The review was highly illustrated to assist the reader in understanding the embryology. There also was a brief section noting the congenital abnormalities that may arise when the embryology goes awry.

Learning Objective: To understand how the lymphatic system develops and what can go wrong when it does not develop normally.