It is estimated that at least 3 million Americans suffer from lymphedema, with a significant proportion developing the disease after surgery and/or radiation therapy for various cancers. Its onset can be sudden or gradual, and may be present in the extremities, trunk, head and neck, external genitalia, and internal organs. In some cases it develops after trauma or deep vein thrombosis, while in others it occurs without obvious cause at different stages in life.1
In order to effectively intervene in cases of lymphatic system disorders, it is imperative to have a general understanding of the anatomy and physiology of the lymphatic system. This chapter will provide an overview of the lymphatic system along with discussions of the stages of lymphedema as well as evidence to support or refute prevailing treatment methods.
PURPOSE OF THE LYMPHATIC SYSTEM
Aside from its role as an immune defender, the lymphatic system drains substances that the venous system is unable to reabsorb. It is a “scavenger” system that removes excess protein molecules, debris, and other matter from the tissue spaces. The movement of fluid from the tissues back into the bloodstream is facilitated by the lymphatic system in order to maintain homeostasis: eliminating chemical imbalances within the interstitial fluid while maintaining blood volume.1,2
OVERVIEW OF THE LYMPHATIC SYSTEM
There are two separate systems of lymphatic drainage, the superficial and deep layers that are separated by fascia which connect the skin to the underlying tissue. Due to the many connections between these two systems, the transport of lymph fluid occurs from distal to proximal and from superficial to deep. The superficial system drains the skin and subcutaneous tissues and the deep system drains the tissues deep to the fascia, including muscle tissue, tendon sheaths, joint structures, nervous tissue, and the periosteum—everything but the skin. Some distal joints on the extremities drain via the superficial layer. Lymphedema presents more frequently in the superficial lymphatic system. The deep lymphatic system is often not involved because the fascia provides compression to resist swelling.1-3
The lymphatic system serves as an accessory route through which fluid can flow from the interstitial spaces into the blood and is composed of lymphatic vessels which absorb and transport lymph fluid, lymph nodes, organs, and lymphatic tissues (which are dedicated to produce and distribute lymphocytes).1-3 The lymph system protects the body by removing foreign material from the lymph fluid; that is, it filters lymph fluid and constantly surveys the body for the presence of foreign material.
Lymph tissues contain macrophages, lymphocytes (T cells or B cells), plasma cells that produce antibodies, and reticular cells that form the lymphoid tissue stroma.2,3
The main organs of the lymph system are the lymph nodes, spleen, thymus, and tonsils. Lymph nodes appear in clusters or chains ...