Cong J C, Chen C S, Zhang H
Colorectal Tumor Surgical Ward, Department of General Surgery, Shengjing Hospital, China Medical University, Shenyang 110004, China.
Zhonghua Wei Chang Wai Ke Za Zhi. 2021 Jul 25;24(7):598-603. doi: 10.3760/cma.j.cn.441530-20201102-00585.
Intersphincteric resection (ISR) involves the anatomy of hiatal ligament, internal and external sphincter and conjoined longitudinal muscle. The hiatal ligament is actually a branch of the longitudinal muscle of rectum, shown as an uneven ring attached to the levator ani muscle. The internal sphincter is the end of the circular muscle of rectum which begins at the level of hiatal ligament formation. The distance from the upper boundary of internal sphincter to dentate line is significantly different among individuals. Although there is adipose tissue in the space between the internal and external sphincters, no evidence of mesentery structure in the anal canal is found as in the rectum. The conjoined longitudinal muscle is the remaining branch of the longitudinal muscle, whose return passes through the external sphincter and ends at the anococcygeal ligament/coccyx after reaching the anal margin. The synergistic action of conjoined longitudinal muscle and the hiatal ligament participates in the defecation process. The individualized difference of ISR-related anatomy affects the operation, especially the anastomosis.
括约肌间切除术（ISR）涉及裂孔韧带、内括约肌、外括约肌和联合纵肌的解剖结构。裂孔韧带实际上是直肠纵肌的一个分支，表现为附着于肛提肌的不平整环状结构。内括约肌是直肠环行肌的末端，起始于裂孔韧带形成水平。内括约肌上界至齿状线的距离在个体间差异显著。虽然内、外括约肌之间存在脂肪组织，但肛管内未发现如直肠那样的系膜结构证据。联合纵肌是纵肌的剩余分支，其折返穿过外括约肌，到达肛缘后止于肛门尾骨韧带/尾骨。联合纵肌与裂孔韧带的协同作用参与排便过程。ISR相关解剖结构的个体差异影响手术操作，尤其是吻合术。
