左半结肠有特殊的双向供血特征，其淋巴回流可同时流向肠系膜上血管和肠系膜下血管周围；较高的血管变异带来对支配血管及主要淋巴回流方向判断的不确定性。充分游离结肠，对满足足够切缘和两侧供血血管的根部结扎尤为重要。对左半结肠血管及系膜解剖变异的认识，为左半结肠癌根治术中选择合适的解剖、吻合手术方式及淋巴结清扫范围提供理论依据。

Left hemi-colon has special bidirectional arterial blood supply, and its lymphatic drainage can drain to the superior mesenteric vessels and inferior mesenteric vessels at the same time. The blood supply of left hemi-colon depends on branch vessels of inferior mesenteric artery(IMA) and middle colic artery(MCA), and high vascular variation brings uncertainty about the dominant vessels and the direction of the main lymphatic drainage. Recently, in addition to the middle colic and left colic artery(LCA),the accessory middle colic artery (AMCA) has been recognized as a feeding artery for the left hemi-colon. Surgery for located in the left hemi-colon cancer is difficult to perform because of the complex anatomy of high vascular variation. In the radical resection of left colon cancer, adequate mobilization of the colon is particularly important to meet the sufficient resection margin and the root ligation of both sides of the blood supply vessels. The anatomical understanding of left hemi-colon vessels provides a theoretical basis for vascular management and lymph node dissection in radical resection of left hemi-colon cancer.