Lymph flow of the digestive tract
Feltman, Barbara
The lymphatic system has long been considered “the stepchild” of medicine.1 For many years, both in this country and al lover the world, patients with lymphedema from any cause were often told there was nothing that could be done for them. Winiwater was the first to introduce physical therapy for lymphedema.2 Later Leduc, Foldi and others expanded on treatment techniques.3
For decades the European medical community has accepted that manual lymphatic drainage is the preferable mode of treating lymphedema.4 The combined treatment is often called Complex Decongestive Physiotherapy,5 referring to a combination of manual lymphatic drainage techniques, specific exercises, skin care, compression bandages, and garments.6 Although this form of therapy is not always successful,7 is it nevertheless considered a typical standard of practice in Europe,8-10 and now in America.11,12
In order to make clinical decisions regarding the individual treatment of each patient, with regard to exercise, manual lymphatic drainage techniques, and application of the multilayered, padded, short-stretch compression bandages, the therapist needs a solid understanding of the anatomical and physiological basis upon which the techniques were built.13 In general it could be said that physical therapy students in America do not receive sufficiently extensive instruction to be able to adequately treat patients with lymphedema, without attending some specific continuing education coursework.14
This paper attempts to consolidate and organize information about the anatomical structures of the lymph system, specifically with regard to the gross anatomy of the digestive system, in order to assist physical therapists in clinical decision making when treating patients with lymphedema of the abdomen and/or lower extremities. In addition, this may assist physical therapists in preparing for national certification in treatment of lymphedema, should such certification become available.15
Questions arise amongst therapists regarding the correct direction to apply manual lymphatic drainage techniques in order to improve lymphatic function in the abdomen and genitalia. Below the diaphragm drainage of all the viscera can be seen to empty via each organ’s set of nodes into the cisterna chyli, and therefore to the left venous angle. Gray’s Anatomy (30th edition) divides the abdominopelvic lymph drainage into parietal and visceral, and describes the drainage from each organ to its nearest group of nodes. Upon first reading of Gray’s chapter 10, it is unclear that these various visceral node groups empty into the cisterna chyli. Drainage efferents from each group of nodes (belonging to the organs) are difficult to follow despite, or perhaps due to, being described in a variety of places within the text.
Clinical decisions regarding correct direction of application of manual lymphatic drainage techniques will be determined in each individual according t9 the typical healthy drainage patterns. The clinician must also have knowledge of the likely trauma to the system in that individual in order to develop alternate lymph flow patterns around the area of damage. Discussion of the many and varied types of damage to the lymphatic system as a result of injury or disease processes is beyond the scope of this paper. Similarly, discussion of the efficacy of various forms of manual lymphatic drainage is not covered here.
Unlike the blood Circulation, which may be described as a circular system involving blood vessels of varying calibers where the driving force is the heart, the lymph system is a unidirectional system. Flow of lymph occurs by intrinsic contraction of the vessel walls in response to changes of internal pressure and of interstitial pressure external to the vessels. Essentially the circulating blood delivers nutrients to the tissues and removes certain of the waste products produced by cell function. The lymphatic system is responsible for returning fluids and plasma proteins to the blood circulation, as well as identifying foreign materials within the body and defending the body via the immune functions.16 In a healthy system, about one tenth of the fluid that needs to be reabsorbed flows via the lymph system,17 the other nine tenths being returned via the venous system.
Anatomy of the lymphatic system may be reviewed by dividing it into gross anatomy and microscopic structures. Looking firstly at microscopic structures it can be seen that the fluid starts out as interstitial fluid, becoming lymph only once it has moved into the initial lymphatic. The initial lymphatics have single endothelial cell walls with a basement membrane and are surrounded by an irregular mesh of fibers and filaments that keep the initial lymphatics open, while the adjacent small blood vessels collapse when edema is present.18 The initial lymphatics empty into the lymphangia, or collecting lymphatics, via the precollectors, which are valueless sections without musculature.19
The collecting lymphatics consist of chains of lymphangia. Each lymphangion is a roughly heart-shaped segment with bicuspid valves. The walls are similar to blood vessels, having a tunica intima, media, and adventitia. The tunica media has smooth muscle cells arranged in both a circular or oblique manner, and a longitudinal distribution to the bicuspid valves.20,21 The intrinsic contraction reflex is in response to stimulation of nerve endings in both the inner and outer walls of the lymphangion, resulting in an asynchronous peristalsis. Reflux is prevented by the bicuspid valves. As the lymphangion contracts, its lumen is decreased, the bicuspid valves are opened, and fluid is moved into the next lymphangion in the chain.
The lymphangia form the collecting lymphatics, which may then be called afferent or efferent vessels in terms.of relationship to the lymph nodes. The afferent lymphatics may enter the lymph node at any point on the cortex, while efferent lymphatics leave from the hilus. As the vessels progress proximally and cephalad, the lumen increases, and the number decreases.22
In terms of gross anatomy, major pathways of lymph flow can be identified. From the head and neck the majority of lymph passes through lymph nodes distributed in the region of the mastoid process, along the inferior borders of the mandible, and then distributed along the length of the internal jugular veins. All of the lymph in the body empties into a region at the junction of the internal jugular and subclavian veins (venous angle). In the upper extremities, lymph flows cephalad and may pass through nodes at the medial elbow, to the axilla and via axillary or brachial trunks or ducts to the ipsilateral venous angle. Some of the flow bypasses the axillary or brachial trunks (ducts) and empties via the deltopectoral nodes to the venous angle.
Lymph from the lower extremities passes through nodes in the popliteal fossae, nodes in the inguinal regions, and through a series of nodes and vessels to tbe cisterna chyli.
The body is divided into lymphotomes, each lymphotome being the drainage area for a specific major group of lymph nodes. The demarcations or boundaries of the lymphotomes are often called anastamoses (watersheds).23 The body is divided into right and left halves anteriorly and posteriorly by a midline anastamosis, and into upper and lower halves by an anastamosis horizontally at the level of the umbilicus anteriorly, and the fifth lumbar vertebra posteriorly. Additional minor divisions have been described, separating the head and neck from the upper lymphotomes at the level of the clavicle anteriorly and the spine of the scapula posteriorly; an upper arm division posteriorly separating medial from lateral upper arm; and a line that curves from the coccyx superiorly and laterally dividing the gluteal region into upper and lower halves, then curving inferomedially to divide the posterior thigh into medial and lateral sections.
Main vessels
One way to describe the flow pathways is to working distally “along the pipeline” from where the lymph fluid empties into the “venous angle.” Afferent to the left venous angle is the thoracic duct, described above. The cisterna chyli is described as an expansion of the vessels at the point where the two lumbar trunks and the intestinal trunk meet to form the distal end of the thoracic duct. The cisterna chyli is situated inferior to the diaphragm, anterior to the bodies of the first and second lumbar vertebrae, posterior and to the right of the descending aorta, and to the left of the inferior vena cava. As the vessel passes through the diaphragm it becomes the thoracic duct, passing cephalad through the posterior mediastinum. At the level of the fifth thoracic vertebra it begins to deviate left, passing behind the arch of the aorta, arches up 3 to 4 cm superior to the left clavicle and then anastamoses with the junction of the left internal jugular and subclavian veinsa,24 sometimes called the venous angle.
The lumbar trunks receive afferents from kidneys, adrenals, pelvic viscera, abdominal and pelvic walls, gonads, and the lower limbs. The intestinal trunk receives afferents from the pre-aortic nodes, and thus from most of the abdominal organs that receive blood supply from the celiac trunk (check to see if this is blood or lymph vessel), and the superior and inferior mesenteric arteries. The pre-aortic nodes are located at the origins of the 3 blood vessels, on the anterior surface of the aorta.
Drainage of the skin and superficial fascia superior to the level of the umbilicus, and thus in the upper lymphotomes, is towards the ipsilateral axillary nodes. Skin and fascia below the level of the umbilicus is to the ipsilateral superficial inguinal nodes. Variations are seen throughout the lymphatic system, as evidenced by lymphoscintigraphic studies.25 Lymph flow from the tissues superficial to the rectus abdominus is to the superficial epigastric lymphatics; that of the skin and fascia overlying the lateral abdominal wall and buttocks follows the iliac crest and descends to the superficial inguinal nodes.
Digestive system and accessory or ans
Lymphatics of the tongue, mouth, and cervical portion of the oesphagus drain mostly via the superior deep cervical nodes to the inferior deep cervical nodes and then to the venous angle. Lymph drainage techniques to promote improved drainage should therefore address the lateral neck and supraclavicular fossa.
The drainage from the thoracic oesphagus is via the mediastinal nodes to the thoracic duct,26 and the abdominal oesphagus into the left gastric lymph nodes, and thus to the cisterna chyli. Clinically, increased flow in the thoracic duct is achieved with breathing exercises. Following the hydrostatic suction theory of lymph flow,27 manual lymph drainage techniques applied to the left supraclavicular fossa would also increase flow within the thoracic duct. Natsugo28 describes drainage from the distal oesophagus that flows both superiorly and inferiorly.
Lymph from the stomach drains via 4 different pathways. Vessels from:
1. The lesser curve of the stomach drain to the left gastric nodes, located along the course of the left gastric blood vessels. These efferents pass to the 3 to 6 celiac nodes located around the celiac trunk at the level of T12,29 and then via the intestinal trunk to the cisterna chyli.
2. The left half of the greater curvature is directly to the celiac nodes.
3. The right half of the greater curvature is via the gastroepiploic nodes to the 8 pyloric nodes found near the termination of the gastroduodenal artery, then to the hepatic nodes along the course of the common hepatic artery, and finally via the celiac nodes to the cisterna chyli. The right gastro-epiploic nodes are situated along the right side of the greater curvature of the stomach, between layers of the greater omentum, alongside the right gastro-epiploic artery.
4. The pyloric portion drains:
a. via the hepatic nodes to celiac nodes to intestinal trunk to cisterna chyli,
b. via the pyloric nodes to the hepatic to the celiac to intestinal trunk to the cisterna chyli, and
c. via the left gastric nodes directly to the cisterna chyli.
The gastric lymphatics begin as a plexus of vessels in the muscularis mucosa. The upper 2/3 of the gastric lamina propria is normally devoid of lymphatics.30
Lymph drainage from the duodenum is both superiorly to the hepatic nodes, then via the celiac nodes, to the intestinal trunk, to the cisterna chyli, and inferiorly to the pre-aortic nodes, then via the intestinal trunk to the cisterna chyli.
The right half of the greater omentum drains together with lymphatics of the right half of the greater curvature of the stomach to the gastro-epiploic nodes, then to pyloric, hepatic, and then celiac nodes to the cisterna chyli. The left half of the greater omentum drains via the pancreaticosplenic nodes, which are situated along the splenic blood vessels. These are afferent to the celiac nodes then to the cisterna chyli via the intestinal trunk.
The drainage from the jejunum and ileum is to the almost 200 mesenteric nodes, which are found along the vasa recta and branches of the superior mesenteric artery between leaves of the peritoneum forming the mesentery. These are afferent to the superior mesenteric nodes, found along the superior mesenteric artery at the level of L1.31 These then empty into the celiac nodes and then via the intestinal trunk to the cisterna chyli. Both the mesenteric nodes and superior mesenteric nodes are important groups in the presence of cancer of the small and large intestine.32 Lymphatics in the jejunum and ileum are called lacteals, most likely due to the milky appearance of the fluid they produce.33 The fluid, also called chyle, contains long-chain fatty acids.34
Lymph drainage from the appendix and cecum is to the appendicular nodes, and then via 3 or 4 collecting lymphatics to the upper and lower ileocolic chain of nodes, situated along the origin and terminal ends of the ileocolic blood vessels. The efferents then pass to the superior mesenteric, to the celiac nodes, to the intestinal trunk and then to the cisterna chyli.
Lymph drainage of the colon is divided into right and left halves. The nodes on the colon are called epicolic nodes.35 The ascending and transverse colon lymphatics drain:
a. to the paracolic node (nodes adjacent to the colon),36
b. to the right colic nodes along the course of the right colic vessels, and
c. to the middle colic nodes along the course of the middle colic vessels.
These 3 groups then empty into the superior mesenteric nodes, the celiac nodes, the intestinal trunk, and finally to cisterns chyli.
The left half of the colon is considered, for lymph flow purposes, to consist of the descending and sigmoid colon. The lymph from these areas flows into the inferior mesenteric nodes of the pre-aortic group found at the level of L3,37 then via the intestinal trunk to the cisterna chyli.38
Of particular interest to the physical therapist working with pelvic floor dysfunction associated with posterior vaginal wall weakness, is the lymph flow from the rectum and anal canal. The drainage is divided into 3 anatomical areas:
1. Lymph from the superior rectum joins that of the sigmoid colon after flowing through the pararectal nodes, to the inferior mesenteric nodes of the pre-aortic group, the intestinal trunk and to the cisterna chyli.
2. From the middle rectum, considered here to be approximately 10 cm of rectum superior to the mucocutaneous line, the lymph vessels pass inferolaterally to the internal iliac nodes. Some of the efferent then go via the external iliac nodes to the common iliac nodes, while other vessels pass directly from the middle rectum to the common iliac nodes. As noted above, the efferents from the common iliac nodes flow to the lateral aortic nodes to the ipsilateral lumbar trunk, which empty into the cisterna chyli.
3. The anal canal lymphatics descend to the skin and fascia of the perineum. Lymph flow from the superficial tissues of the perineum empty into the superficial inguinal nodes, and thus to the external iliac nodes, to the common iliac nodes and on as above to the cisterns chyli.
The liver has 2 separate systems of lymph drainage, superficial and deep. The superficial system drains the entire surface of the organ deep to the peritoneum. This system can be separated to describe the drainage of the diaphragmatic surface, and of the visceral surface. The pathways on the diaphragmatic surface are further divided as follows:
1. The dorsal vessels are further divided into 3 areas
a. the right side drains directly to the celiac nodes;
b. the middle section drains to a small group of nodes situated at the terminal end of the inferior vena cava; and
c. the left aspect drains to the paracardial group of the left gastric nodes, and then to the celiac nodes, the intestinal trunk, and so to the cisterna chyli.
2. The ventral vessels are adjacent to the falciform ligament empty via 2 trunks:
a. through the diaphragm to the terminal part of the inferior vena cava; and
b. downwards and anteriorly to the 1 to 8 hepatic nodes40 which are situated along the common hepatic artery, and whose efferents empty into the celiac nodes, and so to the intestinal trunk to the cisterna chyli.
Lymphatics from the visceral surface of the liver drain directly via the hepatic nodes to the celiac nodes.
The deep lymphatic system of the liver drains the internal substance of the organ. It has an ascending pathway to the nodes at the termination of the inferior vena cava, and a descending pathway to the hepatic nodes, and on via the celiac nodes to the cisterna chyli.
Ito et al41 describe 3 different lymphatic pathways draining the gallbladder in somewhat greater detail than other references. These pathways are:
1. Cholecysto-retropancreatic pathway, considered the main one, which is divided into 2 routes. One spirals posteriorly from the anterior surface of the common bile duct to the right, and the other runs vertically caudal from the posterior surface of the common bile duct.
2. Cholecysto-celiac pathway-these are lymphatics passing from the gallbladder to the left through the hepatoduodenal ligament to the celiac nodes.
3. Cholecysto-mesenteric pathway-some vessels run left and anterior along the portal vein to nodes at the superior mesenteric root.
Ito et al then describe all 3 pathways meeting at a group of abdomino-aortic nodes near the left renal vein, in particular the interaortico-caval nodes. By this description it would seem the authors are describing the left lateral aortic group of nodes as they are described in Gray’s Anatomy.
Gray’s Anatomy,42 in contrast, describes drainage from the gallbladder as being directly to the hepatic nodes and then to the celiac nodes. In addition the lymph from the common bile duct drains either via the hepatic nodes or via the upper pancreaticoduodenal nodes to the celiac nodes.
According to Gray’s Anatomy and other sources,43 there are 3 distinct drainage pathways from the pancreas:
1. The pancreatico-duodenal nodes drain the duodenum and the head of the pancreas to the pyloric nodes, which are afferent to the hepatic nodes.
2. The pancreatico-splenic nodes drain the neck, body, and tail of the pancreas as well as the left half of the lesser curvature of the stomach and are afferent to the celiac nodes.
3. The superior mesenteric nodes are said to drain a portion of the pancreas, stated as “other pancreatic lymphatic channels.”44
Donatini, et al455 differ by describing the following pathways of lymph drainage from the pancreas:
1. The body and tail of the pancreas drain via the left intercelio-mesenteric node and then to the supra and infrarenal nodes.
2. The head of the pancreas has 3 distinct pathways
a. the uncus anterior and posterior aspects) lymph drains along the superior mesenteric route to the right intercelio-mesenteric nodes, to bilateral infra and suprarenal pathways. Rarely the uncus drains directly to the infra and suprarenal paths;
b. the anterosuperior segment lymph drains via the gastroduodenal route, the vessels pass along the superior border of the pancreas and empty into the right intercelio-mesenteric nodes; and
c. the posterosuperior segment drains along the common bile duct and the hepatic artery to the pericholedochal and hepatic pedicular nodes, and then to the right intercelio-mesenteric nodes.
A different description of the pancreatic lymph drainage is seen in Ungeheuer’s46 work. The flow is divided into an upper pathway leading to the common hepatic nodes, the middle and lower pathways to the superior mesenteric nodes. Lymph from the left half of the pancreas flows to the node situated to the left of the origins of the celiac trunk and the superior mesenteric artery.
A third description states that the drainage from the right half is via the retroportal process, from the left via the left retroportal process. There is rapid passage from both into the thoracic duct, which may explain why pancreatic cancer metastasizes so rapidly.47 According to all 3 authors, the lymph from the pancreas eventually drains into the celiac nodes, as described in Gray’s Anatomy.48
All these diverse descriptions of nodal groups underscore the difficulty the clinician has in understanding the assorted pathways of lymph drainage, because the various anatomists and researchers may be describing the same anatomical structures, with different names. It is hoped that this paper will help clinicians visualize the lymph drainage pathways of the digestive system, and this will assist them in clinical decision-making.
ENDNOTES
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Barbara Feltman, PT
Physiotherapy Associates
Broad & Ripple
Indianapolis, Indiana &
President, Feltman Resources
Educational Resources in Women’s Health & Lymphedema Management
Larry Petterborg, PhD
Copyright Rehabilitation in Oncology 2002
Provided by ProQuest Information and Learning Company. All rights Reserved
