Anatomy and Structural Physiology of the Lymphatic System

An understanding of normal lymphatic anatomy is vitally important for practitioners because it provides the baseline imaging data required to distinguish the altered anatomical structures that occur in lymphedema. However, normal anatomy itself is not enough to interpret imaging data in lymphedema because other factors such as lymphangiogenesis, dermal reflux (dermal backflow), and other structural changes are always associated with lymphedema. The lymphatic anatomy changes after lymph node dissection, and the body attempts to maintain lymph drainage in several different ways. The anatomical changes do not occur only at the surgical site but may also occur in any areas downstream of the lymphatic vessels that connect to the removed nodes. In this chapter, we describe normal lymphatic anatomy in the limbs and introduce the anatomical changes that occur in lymphedema.