Key Points
• When lymph nodes increase in size due to inflammatory diseases, the fascia hardens around those areas, thereby inhibiting movement.
• Lymph relies on muscular contractions to circulate throughout the body, leading one to hypothesize that chronic conditions leading to stiffness and less movement will thereby greatly slow down and inhibit the circulation of lymph in the body.

Fascia is a connective tissue that is everywhere in the body. Its import has really only been proven by the research community over the last 15 years, but each new study brings us closer to unraveling all the wonders fascia holds. One new question for us to ponder is the impact fascial manipulation may have on another powerfully subtle body network—the lymphatic system.

The Lymph and Circulatory Systems

The body-wide network known as the lymphatic system is responsible for removing metabolic waste and other unwanted substances from the body. It is vital to proper immune function. As a complementary system to the circulatory system, the lymphatic system is just as pervasive, with lymphatics found everywhere there are blood vessels. In fact, it helps to think of the lymphatic system as a parallel to the circulatory system, but with a more custodial immune function. 
The lymphatic system is comprised of bone marrow, the thymus gland, the spleen, lymphatic vessels, and lymph nodes. The lymphatic vessels can best be understood as “lymph capillaries,” and like a hospital resident following a senior doctor, the lymphatic vessels can be said to “shadow” the circulatory capillaries. To take this analogy further, we can liken the capillaries to the senior doctor who may shunt tasks they don’t want or have time to deal with to the resident—in this case, the lymphatic capillaries. 
In more physiological terms, circulatory capillaries filter about 20 liters of blood every day, with the blood vessels themselves reabsorbing 17 of those filtered liters. The remaining 3 liters remain in the interstitial fluid to be processed and returned to the circulatory system via the lymphatics. Included in those 3 liters are the aforementioned metabolic waste, cellular debris, and sometimes even cancerous cells. 
Lymph nodes are the small (0.1–2.5 centimeters) kidney-shaped “organs” of the lymphatic system. They are surrounded by a fibrous capsule—fascia. Depending on which source you read, humans have anywhere from 450 to 600 lymph nodes. While the nodes are located throughout the body, there are large clusters found in the neck, chest, underarm, abdomen, and groin areas. Unless one is getting a specific lymphatic drainage treatment, these nodes are mostly in areas that tend to be less served in many bodywork modalities.

Understanding the Relationships

Research is underway to look deeper into the relationship among the circulatory capillaries, lymphatic capillaries, collagen, and our favorite intermuscular and intercellular lubricant—hyaluronic acid. Once that research is complete, we should have an even better understanding of how the lymphatic system and fascia interact. Still, even with the facts currently at hand, we can make some highly informed postulations.
While the circulatory system has the heart to keep blood pumping throughout the body, the lymphatic system has no such specialized pump and instead must rely on muscular contractions. This includes both smooth and skeletal muscles, as well as the act of breathing. Lymph circulates through movement. 
As we move from an industrial society to a digital society, our daily tasks—and indeed our online hobbies—tend to limit much of our movement. They usually involve repetitive, functional shortening of specific myofascial units such as the anterior scalene, sternochondral fascia, pectoralis minor, biceps, rectus abdominis, psoas, and the pectineus. All these units also happen to be areas with large populations of lymph nodes.  
The fascial system is a wonderfully adaptive, plastic system designed to respond to supply and demand, with the collagen-producing fibroblasts responding to repetitive pressures, postures, and movements (or lack thereof), and producing more collagen to better reinforce and support our body in whatever it is we do. One can easily hypothesize that chronic contractions (over a period of several months to several years) in the areas mentioned above could lead to more stiffness and less movement in those areas, thereby greatly slowing down and inhibiting the circulation of lymph in the body. We also know that when the size of lymph nodes increases due to inflammatory diseases, the fascia hardens around those areas, which also inhibits movement.¹ 
But this is a two-way street. We have the opportunity to improve the situation by altering the mechanical input into those areas, thereby increasing range of motion and ease of movement. We have the potential to increase the size of the interstitial space, increase the speed limit of the lymphatic system, and allow the metabolic traffic therein to be less congested. We look forward to the research that will help guide the way. 

Note

1. A. Mallick and A. R. Bodenham, “Disorders of Lymph Circulation: Their Relevance to Anaesthesia and Intensive Care,” British Journal of Anaesthesia 91, no. 2 (2003): 265–72.