The cisterna chyli is a small, dilated sac found near the lower area of the thoracic duct in the lumbar region of the body’s abdominal cavity. It is part of the lymphatic system and is the sac that acquires and temporarily holds lymph, the clear fluid from the body’s tissues, as it traverses from the lower body on upward. Located to the right of the abdominal aorta at the back wall of the abdominal cavity, the structure is a large vessel, about 2.4 inches (6 cm) in length.
The thoracic duct begins in the mid-gut area, from the union of the right and left lumbar trunks with the intestinal trunk. This union creates the pathway known as the cisterna chyli, which receives lymph fluid from the intestinal truck and the left and right lumbar lymph trunks. The thoracic duct collects the lymph and delivers it to the bloodstream.
The cisterna chyli is one of two reservoirs that hold lymph and other bodily fluids that are found in the lymphatic system. Along with the cisterna chyli, there is also the cisterna subarachnoidea. This sac, however, plays an integral role, because it is responsible for collecting lymph and acting as a drainage point for “white fat” from the digestive organs.
The lymphatic system has many functions and is an essential component of the body. First and foremost, its main function is to maintain fluid and protein balance within the body. This intricate system returns excess tissue fluid to the blood, and it absorbs fats and vitamins from the digestive tract to deliver them to the circulatory system. It also is most well-known for being part of the immune system, because it acts as a defense mechanism against invading microorganisms and disease.
The lymphatic system is necessary, as it is the network that moves fats throughout the body. Lymphatic vessels deliver lymph from capillaries into large veins in the neck, where then lymph is coursed into the bloodstream and delivered to the heart. Throughout this closed system, there are lymph glands strategically placed within the vessels that filter through the lymph as it traverses through the system. About 10 percent of the fluid in the blood that is filtered by capillaries, along with proteins, becomes trapped in the tissues of the body. This loss of fluid would otherwise be life threatening, but the lymphatic system returns it to the circulatory system, where the cisterna chyli holds it before it is returned to the bloodstream.
The lymphatic system is associated with the health and function of many areas the body, including the digestive system and various organs such as the spleen and thymus, as well as bone marrow. If a lymphatic insufficiency of the internal organs develops, it could lead to various lymphatic system diseases. These might include cancers such lymphoma and auto-immune diseases such as arthritis or scleroderma, to name a few.