The radical surgery aimed at curing the patient should include: 1) partial or total resection of the organ where the primary lesion is located, with negative ends; 2) complete debridement of regional and related distant lymph nodes that may be reached by the tumor. In short, the extent of resection should be wider than the area affected by the tumor. As we all know, in all cancers including gastric cancer, the involvement of lymph nodes will directly affect the cure rate. The respective five-year survival rates for lymph node negative and positive disease &cols=1 target=_blank> cases can correlate many times over. However, regional lymph node metastasis occurs in 12.4-30.0% of cases even in early-stage gastric cancer, while in progressive gastric cancer, the overall patient rate of lymph node metastasis is over 80%. Therefore, effective management of the involved lymph nodes is one of the keys to improve the outcome of gastric cancer surgery. In addition, during surgery, efforts should be made to implement the basic principles of surgical oncology such as “tumor-free” operation method and “whole block resection”. In order to further understand the rationality of the above requirements, and to guide the specific surgical operation, it is appropriate to explain the anatomy related to gastric cancer surgery and the embryological anatomy of the upper abdominal viscera. In order to facilitate the lecture in a uniform manner, we will first briefly introduce the method of gastric division and the method of lymph node grouping and staging related to gastric cancer developed by the Japanese Society for Gastric Cancer Research. The greater curvature of the stomach and the lesser curvature of the stomach are each divided into three equal parts. The three subdivisions of the stomach are: upper, middle and lower parts of the stomach, and the infiltration is limited to one area, which is indicated by C, M or A. If two or three zones are involved, the main partition is written first, and then the partition that is infiltrated, such as MC, AM, MCAD, etc. If the upper cancer extends to the esophagus and the lower cancer infiltrates to the duodenum, they are indicated as CE and AD respectively. The lymph nodes associated with gastric cancer can be divided into 18 groups, which are: 1) right cardia lymph nodes; 2) left posterior cardia lymph nodes; 3) lesser curved lymph nodes; 4) greater curved lymph nodes; 5) suprapyloric lymph nodes; 6) subpyloric lymph nodes; 7) left gastric artery trunk lymph nodes; 8) common hepatic artery trunk lymph nodes; 9) peri-abdominal artery lymph nodes; 10) splenic hilar lymph nodes; 11 splenic artery trunk lymph nodes; 12) liver and duodenal ligaments lymph nodes. The lymph nodes in the hepatic, duodenal ligaments; 13, posterior pancreatic lymph nodes; 14, mesenteric root lymph nodes; 15, peri-arterial lymph nodes; 16, peri-abdominal aortic lymph nodes; 17, inferior thoracic paraesophageal lymph nodes; 18, diaphragmatic lymph nodes. Embryologic anatomy of the upper abdominal viscera associated with gastric cancer surgery The layout of the upper abdominal viscera before rotation. Before rotation, the dorsal mesentery of the stomach is fixed to the posterior membrane wall, and the body tail of the pancreas and the spleen are nurtured in the dorsal mesentery. The anterior aspect of the stomach is held in place by the ventral gastric tract, which is divided by the liver into the sickle ligament and the lesser omentum. Similarly, the spleen divides the dorsal gastric mesentery into the gastrosplenic ligament and the splenorenal ligament. During surgery, if one wishes to free the spleen from the tail of the pancreatic body, the dorsal gastric mesentery can be separated along this imaginary line so that the dorsal gastric mesentery is restored to its embryonic state without damaging any major vessels or other tissues. After rotation of the organ, the head of the pancreas and the tail of the body of the pancreas are brought together on the axis of the superior mesenteric vessels. In adulthood, the remains of different developmental sources between the two can still be observed, such as their own exocrine ducts and arterial blood supply. Thus, according to the embryonic anatomy, the liver, stomach, pancreas and spleen all extend from the foregut and are wrapped in the same mesentery. Although they undergo rotation and rearrangement during development to form the postnatal anatomical state, their lymphatic drainage is still inseparably linked to each other. Therefore, during extended radical surgery for gastric cancer, the pancreas is correctly cut at the junction of the head and body of the pancreas, and the spleen and tail of the pancreas are removed together with the stomach as a whole block, which not only conforms to the embryological anatomy concept, but also ensures that the 10th and 11th groups of lymph nodes are completely removed together with the whole surgical specimen.