Abstract:Background and Aims With the promotion of transanal total mesorectal excision (taTME), it is essential to distinguish and re-understand the anatomical landmarks of perirectal vessels and the transanal approach from different angles. This study was performed to analyze the occurrence and anatomical position of the middle rectal artery (MRA) through the transanal perspective, so as to provide theoretical guidance for the transanal operation of taTME.Methods Clinical data of patients who underwent taTME after preoperative MDT discussion in our hospital between January 2018 and June 2021 were collected. The general clinical characteristics of the patients, the detection rate of MRA, and the intraoperative MRA bleeding were analyzed.Results A total of 86 patients who underwent taTME were included for analysis. MRA was found in 61 cases (70.9%) during taTME surgery, including bilateral MRA in 49 cases (57.0%), all of which ran in the lateral ligament of the rectum. During the dissection and separation of the lateral ligament of the rectum, bleeding occurred in 10 cases (16.4%) of the 61 patients with MRA, of whom, 8 cases had bilateral MRA, and 2 cases had unilateral MRA. Among the 10 cases of bleeding, 8 cases were operated by electric hook and 2 cases were operated by ultrasonic knife; bleeding were managed by electrocoagulation or ultrasonic knife in 9 cases, and Hemoloc was used for hemostasis in only 1 case.Conclusion MRA runs in the lateral rectal ligament, and the finding of MRA is more precise through the transanal view. This anatomical location can not only ensure better radical treatment of the tumor but also provide better protection for surrounding normal tissues.