If the lymph vessels become blocked, damaged, or severed, the fluids will build up in the tissues, leading to oedema (swelling) and if neglected – fibrosis. Similarly, if lymph nodes are surgically removed - for example as part of the treatment to control the spread of cancer to the rest of the body via the lymph system - lymph will not be able to “bridge the gap” without external influences, it will build up in the body tissues, again potentially leading to oedema.
Unlike the cardiovascular system, there is no equivalent of a heart to pump lymph around the body. Instead it relies on the natural movements of the body, including muscle tension and compression, to generate tiny pressures on the lymph vessels to ease the lymph along. One-way valves just a few cells thick prevent a backflow. Around 40% of the tiny lymphatic vessels are found just under the skin surface. Manual Lymphatic Drainage (MLD) attempts to emulate the body’s natural movements to gently help the lymph find alternative pathways through the tissue where lymph vessels &/or lymph nodes have been damaged. MLD is also of great value where there has been damage to skin tissue (burns, infection, ulceration, and hematoma) by speeding up the process by which the the lymph vessels try to move damaged cells away from the area.