横结肠癌发病率低，手术难度大。该术式涉及的解剖学特征与要点包括：其一，横结肠的血管支配复杂、变异多，应沿着横结肠供血血管根部结扎，进行D3站淋巴结清扫。目前结肠中动脉（MCA）根部淋巴结（223组淋巴结）是公认的横结肠癌D3站淋巴结。此外，当右结肠动脉（RCA）存在时，仍应于RCA根部进行结扎。应熟悉横结肠的供血血管变异，特别是MCA、副结肠中动脉（aMCA）、RCA和Henle干的解剖特征，同时注意保护空肠静脉（JV）和肠系膜下静脉（IMV）。其二，横结肠位处胚胎发育时原肠旋转的中心，膜解剖原理复杂。为保证无张力吻合，常需同时游离脾曲与肝曲结肠。理解横结肠的胚胎发育过程和横结肠系膜根结构，有助于完成高效的“三路包抄”脾曲游离。其三，幽门下区结构本质上由胚胎时横结肠系膜、胃系膜和十二指肠系膜相交汇形成，拓扑结构混乱。针对T3~T4期的进展期横结肠癌，仍应行网膜弓淋巴结清扫，而T1~T2期患者可不清扫，理解幽门下区局部解剖关系和胃系膜横结肠系膜间隙等膜解剖结构有助于该区域分离。

The incidence of transverse colon cancer is low and surgery for transverse colon cancer is technically demanded. The anatomical structures that are relevant during transverse colon cancer surgery include: firstly, complicated structural variations in the vascular anatomy of the transverse colon and its implications for D3 lymph node dissection. Root positioning and ligation of the middle colic artery (MCA) as well as right colic artery (RCA) if exists should be performed to remove No. 223 lymph nodes, with an understanding of the variations in the vascular anatomy of MCA, accessory MCA, RCA, Henle's trunk, jejunal vein, and inferior mesenteric vein. Secondly, the transverse colon is located in the center of gastrula rotation during embryonic development, which resulted in complexity in fascia anatomy. However, mobilization of the splenic flexure and/or hepatic flexure colon would frequently be necessary to ensure a tension-free anastomosis. Understanding its embryonic development process as well as the root of transverse mesocolon would be beneficial for an efficient splenic flexure mobilization with "three-way encirclement". Thirdly, the transverse colon, which originates from the midgut and hindgut, and the gastrocolic ligament and greater omentum, which originate from the mesogastrium and mesoduodenum, are intertwined. The above-mentioned topological structure resulted in a difficulty in gastroepiploic lymph node resection, which was recommended for selected advanced cases with T3~T4 stage. Lymph node dissection may not be performed in patients with T1~T2 stage.Thus, it is of great importance to understand this topological structure area, especially the anatomical landmark of the space between transverse mesocolon and mesogastrium.