 In this video, using a male cadaver, a unique dissection of the stem thoraxic and abdominal lymphatics will be demonstrated, not from the typical approach, but from behind after removal of the spinal column. Lymphatics of the trachea and esophagus will be dissected after removal of the spinal column and the thoraxic aorta. The spinal column and posterior portion of the thoraxic cage have already been removed. The left posterior intercostal arteries are cut at their origin from the thoraxic aorta as well as the right posterior intercostal arteries. The posterior intercostal veins are also cut close to their entry to the azygous vein, only the stem of the azygous vein remains. After removal of the intercostal nerves, the right and left sympathetic trunks remain. On the right, we can see the greater splenchnic nerve which originates from the thoraxic sympathetic trunk and pierces the diaphragm to enter the abdominal cavity. The connective tissue between the left medistinal pleura and the thoraxic aorta is removed. The thoraxic aorta can be separated from the surrounding structures. This facilitates view of the lower esophagus and the left bronchus and their structural relationships. The upper thoraxic esophagus runs on the right side of the thoraxic aorta. From a right posterior intercostal artery, a branch originates and divides. Both of these twigs supply the esophagus. Some veins pass between the thoraxic aorta and the esophagus to drain into the azygous vein. These veins seem to originate from the right margin of the esophagus and or trachea. Between the thoraxic aorta and the azygous vein, the thoraxic duct is seen dorsal to the esophagus. It first passes through the aortic hiatus of the diaphragm and then ascends. During its ascending course, the thoraxic duct receives some lymph vessels from the esophagus. Nearly at the level of the arch of the aorta, the thoraxic duct runs obliquely to the left and ascends to reach the left venous angle. Slightly lower to the arch of the aorta, the thoraxic aorta is transacted and reflected in order to clearly view the trachea and esophagus, as well as the surrounding structural relationships. The arch of the aorta crosses over the left bronchus, while the arch of the azygous vein crosses over the right bronchus. Lower to the bronchi, the right and left vagus unite to form the posterior vagal trunk. Again, we trace the esophagus upward until the level of the bifurcation of the trachea. After lifting the thoraxic duct slightly below the bifurcation of the trachea, we can see several lymph vessels from the esophagus which drain into the thoraxic duct. These lymph vessels divide into several vessels and unite again before reaching the thoraxic duct. The cut end of the aorta is shifted to facilitate detailed view of the area surrounding the left bronchus. The left vagus descends behind the bronchus and gives off numerous branches to the left lung and esophagus. Part of the left lung has been cut and removed, and the stem of the left vagus was also cut. At the hylum of the left lung, we can see three ducts, the pulmonary artery above, the inferior pulmonary vein below, and the bronchus in between. In the two grooves between these ducts, lymph nodes are seen close to the hylum of the lung. Along the upper margin of the bronchus, a bronchial artery meanders accompanied by several lymph vessels. We separate the lymph vessels from the artery. By removal of the bronchial artery, we can examine the continuity of the bronchial lymph vessels. The lymph vessels along the lower margin of the left bronchus are connected with the inferior tracheobronchial nodes, while the vessels along the upper margin gather in the space close to the left tracheobronchial angle. The left recurrent laryngeal nerve winds around the arch of the aorta and starts to ascend along the left margin of the trachea within this left tracheobronchial angle. A few lymph nodes are detected within this angle. Slightly lateral to this area, a larger node is observed close to the origin of the left recurrent nerve from the vagus. This node is situated in close proximity to the ligamentum arteriosum. From the node of the ligamentum arteriosum, ascending lymph vessels which run via some nodes in front of the arch of the aorta can be dissected. Now, to return to the left tracheobronchial nodes, lymph vessels from these nodes accompany the left recurrent laryngeal nerve and ascend via several intermediate nodes. Slightly above the tracheobronchial angle, where the left margin of the trachea is compressed by the arch of the aorta, no lymph nodes are found. Only a few lymph vessels are seen. Tracing one of these vessels, it is found to enter the thoraxic duct. Above the arch of the aorta, lymph vessels along the left subclavian artery are clearly seen. Some of them also send branches which run close to the left recurrent laryngeal nerve and drain into the thoraxic duct. Again, we trace the thoraxic duct upwards and finally reach the left venous angle. In the left side dissection, finally the cut end of the esophagus is pulled posteriorly and the left common carotid artery anteriorly in order to obtain a wider view of the spaces between these two structures and the trachea. The complex relationships between the lymphatics and the left recurrent laryngeal nerve become clear. Now in the right side, we can see the right bronchus and the arch of the ozygous vein crossing over this bronchus. Dorsal to the right bronchus, the right vagus descends. Along the vagus, a medium-sized lymph node is seen close to the right tracheobronchial angle. This node gives off numerous lymph vessels and connects the nodes along the bronchi and those of the bifurcation of the trachea. To the right, in addition to the lymphatics along the right margin of the trachea, a vessel winds around on the lateral surface of the right tracheobronchial angle to reach nodes in front of the trachea. Here we observe this relationship from the right. After giving off the recurrent laryngeal nerve, the right vagus crosses the right margin of the trachea and runs obliquely from the front of the subclavian artery to the rear of the bronchus. The right vagus is cut and the superior vena cava is reflected as this vein does not compress the anterior lateral surface of the trachea, lymph nodes are often well developed between these two structures. Now we cut the superior vena cava to observe these lymph nodes. Tracing the lymph vessels from these nodes reveals some vessels which reach the nodes close to the brachiosophallic trunk. To attain a better view of these nodes, we cut and remove some autonomic nerve branches. Tracing the lymph vessels intermingled with autonomic nerve branches, we find that they run along the lower margin of the brachiosophallic and subclavian arteries. These lymph vessels drain into the large node which is in the highest portion of the mediastinum. It is situated adjacent to the curving portion of the right recurrent laryngeal nerve. This node is sometimes referred to as a supreme mediastinal node. We have demonstrated the dissection of the lymphatic surrounding the trachea and esophagus, as well as their connections from the posterior approach. In this video, from the posterior approach, we cut the abdominal aorta and dissect the lymphatic surrounding it to view their relationships with the autonomic nerves. First, we will dissect lymphatics along the iliac vessels of the right side to view the lymphatic pathways and their manner of connection. The ascending lymphatics from this right inter-iliac node run along the medial margin of the common iliac vessels to reach the inferior vena cava. Running between the external iliac artery and vein and then the common iliac vessels, these lymphatics reach the lateral side of IVC. Another lymphatic pathway, which runs lateral to the external and common iliac vessels, also reaches the nodes lateral to IVC. In the left side, the lymphatics followed similar pathways and drained into the nodes of the bifurcation of the aorta and those lateral to the aorta. In the abdomen, first, we dissect the organs behind the peritoneum. In the right side, the diaphragm is reflected to view the liver, the right renal fascia, and the ascending colon. The connective tissue behind the peritoneum is also seen. The connective tissue between the liver and right kidney is now dissected. The right kidney, surrounded by the renal fascia, is now freed. In the left side, we dissect the left kidney. The renal fascia extends dorsal to the descending colon. Lateral to the testicular vessels, we open the renal fascia to view the fusion fascia on the posterior surface of the descending colon. By inserting a finger under the renal fascia, we can reach the lower end of the left kidney. Now, we cut the renal fascia lateral to the kidney and divide the adherent portion between the renal fascia and the peritoneal organs. From the left colic flexure and the spleen, the connective tissue is cleared, freeing the left kidney. To trace the connection between the abdominal aorta and testis, the testis will be extracted from the scrotum. The lower abdominal wall is shifted to view the inguino ring. Medial to the ring, the inferior epigastric artery ascends. Here is a fascia which contains the testicular artery and vein. Upon tracing, we find that this fascia continues to be the renal fascia in the upper abdomen. Interestingly, in the lower portion, the ductus deferens is also contained in this fascia. The testicular vessels and the ductus deferens meet and enter the inguino canal. By cutting the inguino canal and the scrotum, which covers the testicular vessels and ductus deferens, we can free the complete spermatic cord and extract the testis. The fascia containing the testicular vessels and ductus deferens is first a flat sheet, but inside the inguino canal, it surrounds the spermatic cord like a sheath. Now we will transact and remove the aorta. We cut it at the level of the bifurcation of the trachea and reflect it quarterly. The left inferior phrenic artery, which originated independently, is cut. Likewise, we dissect the ciliac trunk and cut it. Close to the ciliac trunk is the origin of the superior mesenteric artery, which we cut. Pulling the artery, we can strip it away from the adventitia and leave this sheath intact. Next, we come to the right and left renal arteries. First, we cut the right renal artery and the left. Further stripping the aorta, we arrive at the inferior mesenteric artery and cut it also. Finally, we transact the aorta slightly above the bifurcation of the aorta. With the extracted aorta rotated, we can visualize the close proximity of the origins of the ciliac trunk and the superior mesenteric artery. Here, we can see the groove which cradled the aorta. We carefully dissect the areolar tissue sheet in front of the abdominal aorta by using forceps. The autonomic nervous network anterior and lateral to the aorta has been dissected. Autonomic nerve plexuses develop above as well as below the left renal vein. The plexus above this vein encircles the combined ciliac trunk and superior mesenteric artery origins. The lower plexus forms a U-shaped loop just below the inferior mesenteric artery. The lower most aortic plexus forms a V-shaped union near the level of the bifurcation of the aorta. This is the superior hypogastric plexus. The superior hypogastric plexus again bifurcates into the right and left hypogastric nerves. By pulling the right hypogastric nerve, we can move the superior hypogastric plexus. Numerous lymph nodes are caught within the network of the aortic plexus. The connective lymph vessels between these nodes are intermingled with nerves of this plexus. Tracing the lymphatics upward, we reach a large node just below the left renal vein. Ventral to the abdominal aorta and also along its left and right margins, numerous lymph nodes and their connecting vessels are detected. In general, the aortic plexus tends to be in close contact with the aortic wall. In other words, the lymphatics are situated relatively outside of the nerve plexus. Now we will observe this plexus and the lymphatics surrounding the aorta from the front. Within the lower angle formed between the inferior vena cava and the left renal vein, a few large nodes are dissected. Lymph vessels along the superior mesenteric artery drain into these nodes. This level is critical as it is a convergence area for the lymphatics of the abdominal visceral organs. Also along the superior mesenteric artery, the autonomic nerves communicate with the aortic plexus. Numerous branches of the aortic plexus continue along the inferior mesenteric artery. With the inferior mesenteric artery slightly lifted, we can see the V-shaped superior hypogastric plexus, which is mainly formed by the union of the right and left lumbar splenchnic nerves. Some fibers from the ciliac and aortic plexuses also descend along the aorta to contribute to the superior hypogastric plexus, although these seem minor compared to the contribution of the right and left lumbar splenchnic nerves. From the posterior approach, after removal of the renal fascia, the right renal artery and vein are shown. Along the renal artery and vein, some lymph vessels and nodes have been dissected. Posterior and caudal to the renal artery, relatively large nodes are seen. Numerous lymph vessels from these nodes form complicated networks and finally drain into the nodes on the right side of the ciliac and superior mesenteric arteries. From these critical nodes, thick lymph vessels arise and unite to continue to the thoracic duct. Again, we trace the complete course of the lymph vessels from the posterior surface of the right renal artery and vein all the way to the thoracic duct. Here we reflect the left kidney to the right and dissect the pancreas body and tail together with the spleen from behind. The spleen and the pancreas body and tail can be seen. Below the vividly meandering splenchnic artery, the straight splenchnic vein runs along the upper margin of the pancreas. Along the upper margin of the splenchnic artery, some well-developed lymph nodes are dissected. In the space between the splenchnic artery and vein, some nodes are found which are connected like a chain. Near the union of the splenchnic vein and the superior mesenteric vein, a few lymph nodes are also detected along the inferior mesenteric vein. This level approximately corresponds to the left renal artery and vein. Slightly cranial to this level, you can see the left supra renal gland which has rich arteries as well as lymph vessels. Now we will consider the lymphatics of the testis. Due to the high origin of the testis, its vessels travel a great distance. After dissecting the fascia between the testicular vessels and doctor's deference, we trace the lymphatics from the left testis upwards to the level of the aorta and inferior vena cava. Medial to the relatively thick vein, we trace a lymph vessel upwards. Lateral to this vein, along a serpentine-like artery, we trace lymphatics upwards. Again, returning to the lymph vessel medial to the vein, we trace it even more cranially and find that it crosses anterior to the ureter and continues to the lateral aortic lymph nodes. Here, just above the crossing of the ureter and testicular vein, by slightly shifting the vein, we see the relatively thick testicular artery and lymphatics surrounding it. These testicular lymphatics are joined by numerous descending renal lymphatics. These lymphatics run cranialward and cross the left renal artery to join the lateral aortic lymphatics. Shifting the lateral aortic lymphatics, we see some vessels run transversely and to the right along the left renal vein. These then unite with the interaortical cable lymphatics and continue to drain into the thoraxic duct. Now we will trace the pathway from the iliac chain to the thoraxic duct. The right and left iliac chains converge at the area near the aorta. In front of the aorta, there is a well-developed autonomic nerve plexus. Just below the inferior mesenteric artery, this plexus is particularly well-developed and it conceals the lymphatics so that they are not distinguishable. In the area between the inferior mesenteric artery and the left renal vein, the nerve plexus is not so developed and thus we can see numerous nodes caught within the network. The level of the left renal vein should be emphasized as there are numerous lymphatic connections between the left and right sides. In the area surrounding the ciliac trunk and superior mesenteric artery, the lymphatics are well-developed. Interestingly, rather than directly draining into the thoraxic duct, most lymphatics first descend and then drain into the thoraxic duct. A few independent lymphatics pierce the right crust of the diaphragm and then continue to the thoraxic duct. By cutting the right crust of the diaphragm, the lower most portion of the esophagus comes into view. Surrounding the esophagus is the well-developed phrenosophageal ligament. A branch of the left inferior phrenic artery passes close to the left margin of the esophagus and sends a cardiosophageal branch to the lower end of the esophagus. After removal of the diaphragm, we can see the thoraxic duct. Now we will trace the thoraxic duct to its terminal portion. In order to trace the thoraxic duct, we must remove the arteries which conceal the pathway. First, we cut the left vertebral artery and then the left subclavian artery. Now we have reached the arched portion of the thoraxic duct. The left sympathetic trunk runs longitudinally nearby and dorsally crosses the thoraxic duct. For a better view, we cut the left sympathetic trunk. A large vein comes into view. The thoraxic duct arches ventral to this vein. Tracing this vein, we find that it exits the foremen transversarium of the sixth cervical vertebra. Therefore, it can be identified as the left vertebral vein. We cut and remove the left vertebral vein. Finally, we confirm that the thoraxic duct drains into the left venous angle. We have demonstrated the paraortic lymphatics and the thoraxic duct from the posterior approach.